Oort cloud - Wikipedia

Oort cloud - Wikipedia
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Distant planetesimals in the Solar System
This article is about the outer Oort cloud. For the inner Oort cloud, see
Hills cloud
The distance from the Oort cloud to the interior of the Solar System, and two of the nearest stars, is measured in
astronomical units
. The scale is
logarithmic
: each indicated distance is ten times as far out as the previous distance. The red arrow indicates the projected location, in 2025–2027, of the
space probe
Voyager 1
, which may reach the Oort cloud about 300 years later.
An
artist's impression
of the Oort cloud and the
Kuiper belt
(inset); the sizes of objects are over-scaled for visibility.
The
Oort cloud
(pronounced
ɔːr
ORT
or
ʊər
OORT
),
sometimes called the
Öpik–Oort cloud
is
theorized
to be a cloud of billions of
icy
planetesimals
surrounding the
Sun
at distances ranging from 2,000 to 200,000
AU
(0.03 to 3.2
light-years
).
Its existence was proposed in 1950 by the Dutch
astronomer
Jan Oort
, in whose honor the idea was later named.
Oort proposed that the bodies in this cloud replenish and keep constant the number of
long-period comets
entering the
inner Solar System
—where they are eventually consumed and destroyed during close approaches to the Sun.
The cloud is thought to encompass two regions: a
disc-shaped
inner Oort cloud approximately aligned with the
solar ecliptic
(also called its
Hills cloud
) and a
spherical
outer Oort cloud enclosing the entire
Solar System
. Both regions lie well beyond the
heliosphere
and are in
interstellar space
The innermost portion of the Oort cloud is more than a thousand times as far from the Sun as the
Kuiper belt
, the
scattered disc
and the
detached objects
—three nearer reservoirs of
trans-Neptunian objects
The outer limit of the Oort cloud defines the
cosmographic
boundary of the
Solar System
. This area is defined by the Sun's
Hill sphere
, and hence lies at the interface between solar and galactic gravitational dominion.
10
The outer Oort cloud is only loosely bound to the Solar System and its constituents are easily affected by the gravitational pulls of
passing stars
, the
Milky Way
itself and the cloud's own microgravity.
11
These forces served to moderate and render more circular the highly eccentric orbits of material ejected from the inner Solar System during its
early phases of development
. The circular orbits of material in the Oort disc are largely thanks to this galactic gravitational torquing.
12
13
By the same token, galactic interference in the motion of Oort bodies occasionally dislodges
comets
from their orbits within the cloud, sending them into the
inner Solar System
Based on their orbits, most but not all of the
short-period comets
appear to have come from the Oort disc. Other short-period comets may have originated from the far larger spherical cloud.
14
Astronomers hypothesize that the material presently in the Oort cloud formed much closer to the Sun, in the
protoplanetary disc
, and was then scattered far into space through the gravitational influence of the
giant planets
No direct observation of the Oort cloud is possible with present imaging technology.
15
Nevertheless, the cloud is thought to be the source that replenishes most
long-period
and
Halley-type
comets, which are eventually consumed by their close approaches to the Sun after entering the inner Solar System. The cloud may also serve the same function for many of the
centaurs
and
Jupiter-family comets
14
Types of
distant minor planets
Centaurs
Neptune trojans
Trans-Neptunian objects
(TNOs)
Kuiper belt objects
(KBOs)
Classical KBOs
(cubewanos)
Resonant KBOs
Plutinos
(2:3 resonance)
Twotinos
(1:2 resonance)
Scattered disc objects
(SDOs)
Resonant SDOs
Extreme trans-Neptunian objects
Detached objects
Sednoids
Oort cloud objects
(ICO/OCOs)
Development of theory
edit
By the early 20th century, astronomers had identified two main types of comets: short-period comets (also called
ecliptic
comets) and long-period comets (also called
nearly
isotropic
comets).
16
Ecliptic comets have relatively small orbits aligned near the
ecliptic plane
and are not found much farther than the
Kuiper cliff
around 50 AU from the Sun (the orbit of
Neptune
averages about 30 AU and
177P/Barnard
's aphelion lies at around 48 AU). Long-period comets, on the other hand, travel in very large orbits thousands of AU from the Sun and are isotropically distributed. This means long-period comets appear from every direction in the sky, both above and below the ecliptic plane.
17
In 1907,
Armin Otto Leuschner
showed that comet trajectories were related to observation time: Short times implied assumed
parabolic trajectories
, and longer times implied
elliptical orbits
. Leuschner conjectured that better statistics would show that comets had elliptical orbits and were permanent members of the Solar System that would return to the inner Solar System after long intervals during which they were invisible to Earth-based astronomy.
18
In 1932, the
Estonian
astronomer
Ernst Öpik
proposed a reservoir of long-period comets in the form of an orbiting cloud at the outermost edge of the
Solar System
19
Dutch
astronomer
Jan Oort
revived this idea in 1950 to resolve a paradox about the origin of comets. The following facts are not easily reconcilable with the highly elliptical orbits in which long-period comets are always found:
Over millions and billions of years the orbits of Oort cloud comets are unstable.
Celestial dynamics
dictate that a comet will eventually be pulled away by a passing star, collide with the Sun or a planet, or be ejected from the Solar System through planetary
perturbations
Moreover, the volatile composition of comets means that as they repeatedly approach the Sun,
radiation
gradually boils off these volatiles until the comet splits or develops an insulating crust that prevents further
outgassing
20
Oort reasoned that comets with orbits that closely approach the Sun cannot have been doing so since the condensation of the protoplanetary disc, more than 4.5 billion years ago. Hence long-period comets could not have formed in the current orbits in which they are always discovered and must have been held in an outer reservoir for nearly all of their existence.
20
21
17
Oort also studied tables of
ephemerides
for long-period comets and discovered that there is a curious concentration of long-period comets whose farthest retreat from the Sun (their
aphelia
) cluster around 20,000 AU. This suggested a reservoir at that distance with a spherical,
isotropic
distribution. He also proposed that the relatively rare comets with orbits of about 10,000 AU probably went through one or more orbits into the inner Solar System and there had their orbits drawn inward by the
gravity
of the planets.
17
Structure and composition
edit
The presumed distance of the Oort cloud compared to the rest of the Solar System
The Oort cloud is thought to occupy a vast space somewhere between 2,000 and 5,000 AU (0.03 and 0.08 ly)
17
from the Sun to as far out as 50,000 AU (0.79 ly) or even 100,000 to 200,000 AU (1.58 to 3.16 ly).
17
The region can be subdivided into a spherical outer Oort cloud with a radius of some 20,000–50,000 AU (0.32–0.79 ly) and a
torus
-shaped inner Oort cloud with a radius of 2,000–20,000 AU (0.03–0.32 ly).
The inner Oort cloud is sometimes known as the
Hills cloud
, named for
Jack G. Hills
, who proposed its existence in 1981.
22
Models predict the inner cloud to be much the denser of the two, having tens or hundreds of times as many cometary nuclei as the outer cloud.
22
23
24
The Hills cloud is thought to be necessary to explain the continued existence of the Oort cloud after billions of years.
25
Because it lies at the interface between the dominion of Solar and galactic gravitation, the objects comprising the outer Oort cloud are only weakly bound to the Sun. This in turn allows small perturbations from nearby stars or the Milky Way itself to inject long-period (and possibly
Halley-type
) comets inside the orbit of
Neptune
This process ought to have depleted the sparser, outer cloud and yet long-period comets with orbits well above or below the ecliptic continue to be observed. The Hills cloud is thought to be a secondary reservoir of cometary nuclei and the source of replenishment for the tenuous outer cloud as the latter's numbers are gradually depleted through losses to the inner Solar System.
26
The outer Oort cloud may have trillions of objects larger than 1 km (0.6 mi),
and billions with diameters of 20-kilometre (12 mi). This corresponds to an
absolute magnitude
of more than 11.
27
On this analysis, "neighboring" objects in the outer cloud are separated by a significant fraction of 1 AU, tens of millions of kilometres.
14
28
The outer cloud's total mass is not known, but assuming that
Halley's Comet
is a suitable proxy for the nuclei composing the outer Oort cloud, their combined mass would be roughly 3
10
25
kilograms (6.6
10
25
lb), or five Earth masses.
29
Formerly the outer cloud was thought to be more massive by two orders of magnitude, containing up to 380 Earth masses,
30
but improved knowledge of the size distribution of long-period comets has led to lower estimates. No estimates of the mass of the inner Oort cloud have been published as of 2023.
If analyses of comets are representative of the whole, the vast majority of Oort-cloud objects consist of
ices
such as
water
methane
ethane
carbon monoxide
and
hydrogen cyanide
31
However, the discovery of the object
1996 PW
, an object whose appearance was consistent with a
D-type asteroid
32
33
in an orbit typical of a long-period comet, prompted theoretical research that suggests that the Oort cloud population consists of roughly one to two percent asteroids.
34
Analysis of the carbon and nitrogen
isotope
ratios in both the long-period and Jupiter-family comets shows little difference between the two, despite their presumably vastly separate regions of origin. This suggests that both originated from the original protosolar cloud,
35
a conclusion also supported by studies of granular size in Oort-cloud comets
36
and by the recent impact study of Jupiter-family comet
Tempel 1
37
Origin
edit
The Oort cloud is thought to have developed after the
formation of planets
from the primordial
protoplanetary disc
approximately 4.6 billion years ago.
The most widely accepted hypothesis is that the Oort cloud's objects initially coalesced much closer to the Sun as part of the same process that formed the
planets
and
minor planets
. After formation, strong gravitational interactions with young gas giants, such as Jupiter, scattered the objects into extremely wide
elliptical
or
parabolic orbits
that were subsequently modified by perturbations from passing stars and giant molecular clouds into long-lived orbits detached from the gas giant region.
38
Recent research has been cited by NASA hypothesizing that a large number of Oort cloud objects are the product of an exchange of materials between the Sun and its sibling stars as they formed and drifted apart and it is suggested that many—possibly the majority—of Oort cloud objects did not form in close proximity to the Sun.
39
Simulations of the evolution of the Oort cloud from the beginnings of the Solar System to the present suggest that the cloud's mass peaked around 800 million years after formation, as the pace of accretion and collision slowed and depletion began to overtake supply.
Models by
Julio Ángel Fernández
suggest that the
scattered disc
, which is the main source for
periodic comets
in the Solar System, might also be the primary source for Oort cloud objects. According to the models, about half of the objects scattered travel outward toward the Oort cloud, whereas a quarter are shifted inward to Jupiter's orbit, and a quarter are ejected on
hyperbolic
orbits. The scattered disc might still be supplying the Oort cloud with material.
40
41
A third of the scattered disc's population is likely to end up in the Oort cloud after 2.5 billion years.
42
Computer models suggest that collisions of cometary debris during the formation period play a far greater role than was previously thought. According to these models, the number of collisions early in the Solar System's history was so great that most comets were destroyed before they reached the Oort cloud. Therefore, the current cumulative mass of the Oort cloud is far less than was once suspected.
43
The estimated mass of the cloud is only a small part of the 50–100 Earth masses of ejected material.
Gravitational interaction with nearby stars and
galactic tides
modified cometary orbits to make them more circular. This explains the nearly spherical shape of the outer Oort cloud.
On the other hand, the
Hills cloud
, which is bound more strongly to the Sun, has not acquired a spherical shape. Recent studies have shown that the formation of the Oort cloud is broadly compatible with the hypothesis that the
Solar System
formed as part of an embedded
cluster
of 200–400 stars. These early stars likely played a role in the cloud's formation, since the number of close stellar passages within the cluster was much higher than today, leading to far more frequent perturbations.
44
In June 2010
Harold F. Levison
and others suggested on the basis of enhanced computer simulations that the Sun "captured comets from other stars while it was in its
birth cluster
." Their results imply that "a substantial fraction of the Oort cloud comets, perhaps exceeding 90%, are from the protoplanetary discs of other stars."
45
46
In July 2020 Amir Siraj and
Avi Loeb
found that a captured origin for the Oort Cloud in the Sun's
birth cluster
could address the theoretical tension in explaining the observed ratio of outer Oort cloud to
scattered disc
objects, and in addition could increase the chances of a captured
Planet Nine
47
48
49
Comets
edit
Further information:
Halley-type comet
and
List of Halley-type comets
Further information:
Jupiter-family comet
and
List of periodic comets § List of unnumbered Jupiter-Family comets
Further information:
List of centaurs (small Solar System bodies)
Comets
are remnants from the formation of the Solar system around 4 billion years ago, stored in two separate areas, the
Kuiper belt
and the Oort cloud.
50
Short-period comets (those with orbits of up to 200 years) are generally accepted to have emerged from either the Kuiper belt or the scattered disc, which are two linked flat discs of icy debris beyond Neptune's orbit at 30 AU and jointly extending out beyond 100 AU. Very long-period comets, such as
C/1999 F1 (Catalina)
, whose orbits last for millions of years, are thought to originate directly from the outer Oort cloud.
51
Other comets modeled to have come directly from the outer Oort cloud include
C/2006 P1 (McNaught)
C/2010 X1 (Elenin)
Comet ISON
C/2013 A1 (Siding Spring)
C/2017 K2
, and
C/2017 T2 (PANSTARRS)
. The orbits within the Kuiper belt are relatively stable, so very few comets are thought to originate there. The scattered disc, however, is dynamically active and is far more likely to be the place of origin for comets.
17
Comets pass from the scattered disc into the realm of the outer planets, becoming what are known as
centaurs
52
53
These centaurs are then sent farther inward to become the short-period comets.
54
There are two main types of short-period comets: Jupiter-family comets (with orbits smaller than 5 AU) and Halley-family comets. Halley-family comets, named after
Halley's Comet
, are distinct because, even though they are short-period comets, they are thought to come from the Oort Cloud rather than the scattered disc.
55
56
Based on their orbits, it is suggested they were long-period comets that were captured by the gravity of the giant planets and sent into the inner Solar System.
21
This process may have also created the present orbits of a significant fraction of the Jupiter-family comets, although the majority of such comets are thought to have originated in the scattered disc.
14
Oort noted that the number of returning comets was far less than his model predicted, and this issue, known as "cometary fading", has yet to be resolved.
57
No dynamical process is known to explain the smaller number of observed comets than Oort estimated. Hypotheses for this discrepancy include the destruction of comets due to tidal stresses, impact or heating; the loss of all
volatiles
, rendering some comets invisible, or the formation of a non-volatile crust on the surface.
58
Dynamical studies of hypothetical Oort cloud comets have estimated that their occurrence in the
outer-planet
region would be several times higher than in the inner-planet region. This discrepancy may be due to the gravitational attraction of
Jupiter
, which acts as a kind of barrier, trapping incoming comets and causing them to collide with it, just as it did with
Comet Shoemaker–Levy 9
in 1994.
59
An example of a typical dynamically old comet with an origin in the Oort cloud could be
C/2018 F4
60
Sedna and similar objects
edit
See also:
Sedna (dwarf planet)
Several observed objects have been proposed as members of the inner Oort cloud.
61
Sedna, first reported in 2004, has a highly eccentric orbit with a perihelion distances of 76 AU.
62
2012 VP
113
, observed in 2012, has a larger perihelion (closest approach to the Sun) but its aphelion is half of Sedna's.
63
64
Other candidate objects
65
include
2010 GB
174
66
and
474640 Alicanto
(originally 2004 VN
112
).
67
Tidal effects
edit
Further information:
Galactic tide
Most of the comets seen close to the Sun seem to have reached their current positions through gravitational perturbation of the Oort cloud by the
tidal force
exerted by the
Milky Way
. Just as the
Moon
's tidal force deforms Earth's oceans, causing the tides to rise and fall, the galactic tide also distorts the orbits of bodies in the
outer Solar System
68
In the charted regions of the Solar System, these effects are negligible compared to the gravity of the Sun, but in the outer reaches of the system, the Sun's gravity is weaker and the gradient of the Milky Way's gravitational
Galactic Center
compresses it along the other two axes; these small perturbations can shift orbits in the Oort cloud to bring objects close to the Sun.
69
The point at which the Sun's gravity concedes its influence to the galactic tide is called the tidal truncation radius. It lies at a radius of 100,000 to 200,000 AU, and marks the outer boundary of the Oort cloud.
17
Some scholars theorize that the galactic tide may have contributed to the formation of the Oort cloud by increasing the
perihelia
(smallest distances to the Sun) of
planetesimals
with large aphelia (largest distances to the Sun).
70
The effects of the galactic tide are quite complex, and depend heavily on the behaviour of individual objects within a planetary system. Cumulatively, however, the effect can be quite significant: up to 90% of all comets originating from the Oort cloud may be the result of the galactic tide.
71
Statistical models of the observed orbits of long-period comets argue that the galactic tide is the principal means by which their orbits are perturbed toward the inner Solar System.
72
Stellar perturbations and stellar companion hypotheses
edit
Besides the
galactic tide
, the main trigger for sending comets into the inner Solar System is thought to be interaction between the Sun's Oort cloud and the gravitational fields of nearby stars
or giant
molecular clouds
59
The orbit of the Sun through the plane of the Milky Way sometimes brings it into relatively
close proximity to other stellar systems
. For example, it is hypothesized that 70,000 years ago
Scholz's Star
passed through the outer Oort cloud (although its low mass and high relative velocity limited its effect).
73
74
During the next 10 million years the known star with the greatest possibility of perturbing the Oort cloud is
Gliese 710
75
This process could also scatter Oort cloud objects out of the ecliptic plane, potentially also explaining its spherical distribution.
75
76
In 1984,
physicist
Richard A. Muller
postulated that the Sun has an as-yet undetected companion, either a
brown dwarf
or a
red dwarf
, in an elliptical orbit within the Oort cloud.
77
This object, known as
Nemesis
, was hypothesized to pass through a portion of the Oort cloud approximately every 26 million years, bombarding the inner Solar System with comets. However, to date no evidence of Nemesis has been found, and many lines of evidence (such as
crater counts
), have thrown its existence into doubt.
78
79
Recent scientific analysis no longer supports the idea that extinctions on Earth happen at regular, repeating intervals.
80
Thus, the Nemesis hypothesis is no longer needed to explain current assumptions.
80
A somewhat similar hypothesis was advanced by astronomer
John J. Matese
of the
University of Louisiana at Lafayette
in 2002. He contends that more comets are arriving in the inner Solar System from a particular region of the postulated Oort cloud than can be explained by the galactic tide or stellar perturbations alone, and that the most likely cause would be a
Jupiter
-mass object in a distant orbit.
81
This hypothetical
gas giant
was nicknamed
Tyche
. The
WISE mission
, an
all-sky survey
using
parallax
measurements in order to clarify local star distances, was capable of proving or disproving the Tyche hypothesis.
80
In 2014, NASA announced that the WISE survey had ruled out any object as they had defined it.
82
Future exploration
edit
Artist's impression
of the
Voyager
spacecraft
Voyager 1
the most distant spacecraft,
will not reach the Oort cloud for about 300 years
83
and would take about 30,000 years to pass through it.
84
In the 1980s, there was a concept for a probe that could reach 1,000 AU in 50 years, called
TAU
; among its missions would be to look for the Oort cloud.
85
solar sail
could reach the cloud in a human lifetime without requiring significant
space infrastructure
, depending on the model.
86
In the 2014 Announcement of Opportunity for the
Discovery program
, an observatory to detect the objects in the Oort cloud (and Kuiper belt) called the
"Whipple Mission"
was proposed.
87
It would monitor distant stars with a photometer, looking for transits up to 10,000 AU away.
87
The observatory was proposed for halo orbiting around L2 with a suggested 5-year mission.
87
It was also suggested that the
Kepler space telescope
could have been capable of detecting objects in the Oort cloud.
88
See also
edit
Astronomy portal
Stars portal
Spaceflight portal
Outer space portal
Solar system portal
Heliosphere
Hills cloud
Interstellar object
List of possible dwarf planets
List of trans-Neptunian objects
Nemesis (hypothetical star)
Planets beyond Neptune
Scattered disc
Tyche (hypothetical planet)
References
edit
"Oort"
Oxford English Dictionary
(Online ed.). Oxford University Press.
(Subscription or
participating institution membership
required.)
Whipple, F. L.
; Turner, G.; McDonnell, J. A. M.; Wallis, M. K. (1987-09-30). "A Review of Cometary Sciences".
Philosophical Transactions of the Royal Society A
323
(1572): 339–347 [341].
Bibcode
1987RSPTA.323..339W
doi
10.1098/rsta.1987.0090
S2CID
119801256
Williams, Matt (August 10, 2015).
"What is the Oort Cloud?"
Universe Today
Archived
from the original on January 23, 2018
. Retrieved
May 21,
2021
Lectures notes from 35th Saas-Fee advanced course.
Alessandro Morbidelli (2006). "Origin and dynamical evolution of comets and their reservoirs of water ammonia and methane".
arXiv
astro-ph/0512256
van der Kruit, Pieter C. (2020).
Master of Galactic Astronomy: A Biography of Jan Hendrik Oort
. Springer.
Bibcode
2021mgab.book.....K
Whipple, Fred L. (1978). "The Oort Cloud". In Tom Gehrels (ed.).
Protostars and Planets
. University of Arizona Press.
Redd, Nola Taylor (October 4, 2018).
"Oort Cloud: The Outer Solar System's Icy Shell"
Space.com
Archived
from the original on January 26, 2021
. Retrieved
August 18,
2020
"Catalog Page for PIA17046"
Photo Journal
. NASA. 12 September 2013.
Archived
from the original on May 24, 2019
. Retrieved
April 27,
2014
Dones, Luke (2004). Hans Rickman and Michael Festou (ed.).
The Origin and Evolution of the Oort Cloud
. Cambridge University Press. pp.
153–
174.
"Kuiper Belt & Oort Cloud"
NASA Solar System Exploration web site
NASA
. Archived from
the original
on 2003-12-26
. Retrieved
2011-08-08
Correa-Otto, J. A.; Calandra, M. F. (2019).
"The stability in the most external region of the Oort Cloud: The evolution of the ejected comets"
Monthly Notices of the Royal Astronomical Society
490
(2):
2495–
2504.
arXiv
1901.05964
doi
10.1093/mnras/stz2755
Fouchard, Marc; Froeschlé, Christiane; Valsecchi, Giovanni; Rickman, Hans (27 September 2006). "Long-term effects of the Galactic tide on cometary dynamics".
Celestial Mechanics and Dynamical Astronomy
95
1–
4):
299–
326.
Bibcode
2006CeMDA..95..299F
doi
10.1007/s10569-006-9027-8
Raymond, Sean (2023-06-21).
"Oort cloud (exo)planets"
PLANETPLANET
Archived
from the original on 2023-07-01
. Retrieved
2023-07-01
V. V. Emelyanenko; D. J. Asher; M. E. Bailey (2007).
"The fundamental role of the Oort Cloud in determining the flux of comets through the planetary system"
Monthly Notices of the Royal Astronomical Society
381
(2):
779–
789.
Bibcode
2007MNRAS.381..779E
CiteSeerX
10.1.1.558.9946
doi
10.1111/j.1365-2966.2007.12269.x
"Oort Cloud"
NASA Solar System Exploration
. 20 June 2023.
Archived
from the original on 2023-06-30
. Retrieved
2023-07-01
Duncan, Martin J.; Levison, Harold F.; Dones, Luke (2004). "Dynamical Evolution of Ecliptic Comets". In Michel Festou, H. U. Keller, and H. A. Weaver (ed.).
Comets II
(PDF)
. University of Arizona Press. pp.
193–
204.
{{
cite book
}}
: CS1 maint: multiple names: editors list (
link
Harold F. Levison; Luke Donnes (2007).
"Comet Populations and Cometary Dynamics"
. In Lucy Ann Adams McFadden; Lucy-Ann Adams; Paul Robert Weissman; Torrence V. Johnson (eds.).
Encyclopedia of the Solar System
(2nd ed.). Amsterdam; Boston: Academic Press. pp.
575–588
ISBN
978-0-12-088589-3
Ley, Willy (April 1967).
"The Orbits of the Comets"
. For Your Information.
Galaxy Science Fiction
. Vol. 25, no. 4. pp.
55–
63.
Ernst Julius Öpik (1932). "Note on Stellar Perturbations of Nearby Parabolic Orbits".
Proceedings of the American Academy of Arts and Sciences
67
(6):
169–
182.
Bibcode
1932PAAAS..67..169O
doi
10.2307/20022899
JSTOR
20022899
Jan Oort (1950). "The structure of the cloud of comets surrounding the Solar System and a hypothesis concerning its origin".
Bulletin of the Astronomical Institutes of the Netherlands
11
91–
110.
Bibcode
1950BAN....11...91O
David C. Jewitt (2001).
"From Kuiper Belt to Cometary Nucleus: The Missing Ultrared Matter"
(PDF)
Astronomical Journal
123
(2):
1039–
1049.
Bibcode
2002AJ....123.1039J
doi
10.1086/338692
S2CID
122240711
. Archived from
the original
(PDF)
on 2020-05-03.
Jack G. Hills (1981).
"Comet showers and the steady-state infall of comets from the Oort Cloud"
Astronomical Journal
86
1730–
1740.
Bibcode
1981AJ.....86.1730H
doi
10.1086/113058
Harold F. Levison; Luke Dones; Martin J. Duncan (2001).
"The Origin of Halley-Type Comets: Probing the Inner Oort Cloud"
Astronomical Journal
121
(4):
2253–
2267.
Bibcode
2001AJ....121.2253L
doi
10.1086/319943
Thomas M. Donahue, ed. (1991).
Planetary Sciences: American and Soviet Research, Proceedings from the U.S.–U.S.S.R. Workshop on Planetary Sciences
. Kathleen Kearney Trivers, and David M. Abramson. National Academy Press. p. 251.
Bibcode
1991psas.conf.....D
doi
10.17226/1790
ISBN
978-0-309-04333-5
Archived
from the original on 2014-11-09
. Retrieved
2008-03-18
Julio A. Fernández (1997).
"The Formation of the Oort Cloud and the Primitive Galactic Environment"
(PDF)
Icarus
219
(1):
106–
119.
Bibcode
1997Icar..129..106F
doi
10.1006/icar.1997.5754
Archived
(PDF)
from the original on 2012-07-24
. Retrieved
2008-03-18
Kaib, Nathan A.; Volk, Kathryn (2022).
"Dynamical Population of Comet Reservoirs"
Comets III
. p. 97.
arXiv
2206.00010
doi
10.2458/azu_uapress_9780816553631-ch004
ISBN
978-0-8165-5363-1
Absolute magnitude is a measure of how bright an object would be if it were 1 au from the Sun and Earth; as opposed to
apparent magnitude
, which measures how bright an object appears from Earth. Because all measurements of absolute magnitude assume the same distance, absolute magnitude is in effect a measurement of an object's brightness. The lower an object's absolute magnitude, the brighter it is.
Paul R. Weissman (1998).
"The Oort Cloud"
Scientific American
. Archived from
the original
on 2012-11-11
. Retrieved
2007-05-26
Paul R. Weissman (1983). "The mass of the Oort Cloud".
Astronomy and Astrophysics
118
(1):
90–
94.
Bibcode
1983A&A...118...90W
Sebastian Buhai.
"On the Origin of the Long Period Comets: Competing theories"
(PDF)
. Utrecht University College. Archived from
the original
(PDF)
on 2006-09-30
. Retrieved
2008-03-29
E. L. Gibb; M. J. Mumma; N. Dello Russo; M. A. DiSanti & K. Magee-Sauer (2003). "Methane in Oort Cloud comets".
Icarus
165
(2):
391–
406.
Bibcode
2003Icar..165..391G
doi
10.1016/S0019-1035(03)00201-X
Rabinowitz, D. L. (August 1996). "1996 PW".
IAU Circular
(6466): 2.
Bibcode
1996IAUC.6466....2R
Davies, John K.; McBride, Neil; Green, Simon F.; Mottola, Stefano; et al. (April 1998). "The Lightcurve and Colors of Unusual Minor Planet 1996 PW".
Icarus
132
(2):
418–
430.
Bibcode
1998Icar..132..418D
doi
10.1006/icar.1998.5888
Paul R. Weissman; Harold F. Levison (1997).
"Origin and Evolution of the Unusual Object 1996 PW: Asteroids from the Oort Cloud?"
Astrophysical Journal
488
(2):
L133–
L136.
Bibcode
1997ApJ...488L.133W
doi
10.1086/310940
D. Hutsemekers; J. Manfroid; E. Jehin; C. Arpigny; A. Cochran; R. Schulz; J.A. Stüwe & J.M. Zucconi (2005). "Isotopic abundances of carbon and nitrogen in Jupiter-family and Oort Cloud comets".
Astronomy and Astrophysics
440
(2):
L21–
L24.
arXiv
astro-ph/0508033
Bibcode
2005A&A...440L..21H
doi
10.1051/0004-6361:200500160
S2CID
9278535
Takafumi Ootsubo; Jun-ichi Watanabe; Hideyo Kawakita; Mitsuhiko Honda & Reiko Furusho (2007). "Grain properties of Oort Cloud comets: Modeling the mineralogical composition of cometary dust from mid-infrared emission features".
Highlights in Planetary Science, 2nd General Assembly of Asia Oceania Geophysical Society
55
(9):
1044–
1049.
Bibcode
2007P&SS...55.1044O
doi
10.1016/j.pss.2006.11.012
Michael J. Mumma; Michael A. DiSanti; Karen Magee-Sauer; et al. (2005).
"Parent Volatiles in Comet 9P/Tempel 1: Before and After Impact"
(PDF)
Science Express
310
(5746):
270–
274.
Bibcode
2005Sci...310..270M
doi
10.1126/science.1119337
PMID
16166477
S2CID
27627764
Archived
(PDF)
from the original on 2018-07-24
. Retrieved
2018-08-02
"Oort Cloud & Sol b?"
. SolStation. Archived from
the original
on 2020-02-14
. Retrieved
2007-05-26
"The Sun Steals Comets from Other Stars"
. NASA. 2010.
Archived
from the original on 2021-01-25
. Retrieved
2017-07-12
Fernández, Julio A. (1997).
"The Formation of the Oort Cloud and the Primitive Galactic Environment"
Icarus
129
(1):
106–
119.
Bibcode
1997Icar..129..106F
doi
10.1006/icar.1997.5754
Julio A. Fernández; Tabaré Gallardo & Adrián Brunini (2004). "The scattered disc population as a source of Oort Cloud comets: evaluation of its current and past role in populating the Oort Cloud".
Icarus
172
(2):
372–
381.
Bibcode
2004Icar..172..372F
doi
10.1016/j.icarus.2004.07.023
hdl
11336/36810
Davies, J. K.; Barrera, L. H. (2004).
The First Decadal Review of the Edgeworth-Kuiper Belt
. Kluwer Academic Publishers.
ISBN
978-1-4020-1781-0
Archived
from the original on 2021-03-06
. Retrieved
2020-10-11
S. Alan Stern; Paul R. Weissman (2001). "Rapid collisional evolution of comets during the formation of the Oort Cloud".
Nature
409
(6820):
589–
591.
Bibcode
2001Natur.409..589S
doi
10.1038/35054508
PMID
11214311
S2CID
205013399
R. Brasser; M. J. Duncan; H.F. Levison (2006). "Embedded star clusters and the formation of the Oort Cloud".
Icarus
184
(1):
59–
82.
Bibcode
2006Icar..184...59B
doi
10.1016/j.icarus.2006.04.010
Levison, Harold; et al. (10 June 2010).
"Capture of the Sun's Oort Cloud from Stars in Its Birth Cluster"
Science
329
(5988):
187–
190.
Bibcode
2010Sci...329..187L
doi
10.1126/science.1187535
PMID
20538912
S2CID
23671821
"Many famous comets originally formed in other solar systems"
Southwest Research Institute® (SwRI®) News
. 10 June 2010. Archived from
the original
on 27 May 2013.
Brasser, R.; Morbidelli, A. (2013-07-01).
"Oort cloud and Scattered Disc formation during a late dynamical instability in the Solar System"
Icarus
225
(1):
40–
49.
arXiv
1303.3098
Bibcode
2013Icar..225...40B
doi
10.1016/j.icarus.2013.03.012
ISSN
0019-1035
S2CID
118654097
Archived
from the original on 2021-03-06
. Retrieved
2020-11-16
Siraj, Amir; Loeb, Abraham (2020-08-18).
"The Case for an Early Solar Binary Companion"
The Astrophysical Journal
899
(2): L24.
arXiv
2007.10339
Bibcode
2020ApJ...899L..24S
doi
10.3847/2041-8213/abac66
ISSN
2041-8213
S2CID
220665422
"The Sun May Have Started Its Life with a Binary Companion"
www.cfa.harvard.edu/
. 2020-08-17.
Archived
from the original on 2021-03-02
. Retrieved
2020-11-16
Alan Stern, S. (August 2003).
"The evolution of comets in the Oort cloud and Kuiper belt"
Nature
424
(6949):
639–
642.
Bibcode
2003Natur.424..639S
doi
10.1038/nature01725
ISSN
0028-0836
PMID
12904784
Horizons
output.
"Barycentric Osculating Orbital Elements for Comet C/1999 F1 (Catalina)"
Archived
from the original on 2021-06-02
. Retrieved
2021-06-01
Solution using the Solar System
Barycenter
. Ephemeris Type:Elements and Center:@0 (To be outside planetary region, inbound epoch 1950 and outbound epoch 2050. For epoch 1950-Jan-01 orbit period is "PR= 1.6E+09 / 365.25 days" = ~4.3 million years)
Harold E. Levison & Luke Dones (2007).
"Chapter 31: Comet Populations and Cometary Dynamics"
Encyclopedia of the Solar System
. pp.
575–588
Bibcode
2007ess..book..575L
doi
10.1016/B978-012088589-3/50035-9
ISBN
978-0-12-088589-3
Jewitt, David (2009).
"The Active Centaurs"
The Astronomical Journal
137
(5):
4296–
4312.
arXiv
0902.4687
Bibcode
2009AJ....137.4296J
doi
10.1088/0004-6256/137/5/4296
J Horner; NW Evans; ME Bailey; DJ Asher (2003).
"The Populations of Comet-like Bodies in the Solar System"
Monthly Notices of the Royal Astronomical Society
343
(4):
1057–
1066.
arXiv
astro-ph/0304319
Bibcode
2003MNRAS.343.1057H
doi
10.1046/j.1365-8711.2003.06714.x
S2CID
2822011
Levison, H. F.; Duncan, M. J. (1997).
"From the Kuiper Belt to Jupiter-Family Comets: The Spatial Distribution of Ecliptic Comets"
Icarus
127
(1):
13–
32.
Bibcode
1997Icar..127...13L
doi
10.1006/icar.1996.5637
Wang, J.-H.; Brasser, R. (2014).
"An Oort Cloud origin of the Halley-type comets"
Astronomy & Astrophysics
563
: A122.
arXiv
1402.2027
Bibcode
2014A&A...563A.122W
doi
10.1051/0004-6361/201322508
Neslušan, L. (1999).
"Fading of long-period comets in near-parabolic orbits"
Astronomy & Astrophysics
351
767–
772.
doi
10.1051/aas:1999605
(inactive 1 July 2025).
{{
cite journal
}}
: CS1 maint: DOI inactive as of July 2025 (
link
Luke Dones; Paul R Weissman; Harold F Levison; Martin J Duncan (2004).
"Oort Cloud Formation and Dynamics"
(PDF)
. In Michel C. Festou; H. Uwe Keller; Harold A. Weaver (eds.).
Comets II
. University of Arizona Press. pp.
153–
173.
Archived
from the original on 2017-08-24
. Retrieved
2008-03-22
Julio A. Fernández (2000). "Long-Period Comets and the Oort Cloud".
Earth, Moon, and Planets
89
1–
4):
325–
343.
Bibcode
2002EM&P...89..325F
doi
10.1023/A:1021571108658
S2CID
189898799
Licandro, Javier; de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl; de Leon, Julia; Serra-Ricart, Miquel; Cabrera-Lavers, Antonio (28 May 2019). "Spectroscopic and dynamical properties of comet C/2018 F4, likely a true average former member of the Oort cloud".
Astronomy and Astrophysics
625
: A133 (6 pages).
arXiv
1903.10838
Bibcode
2019A&A...625A.133L
doi
10.1051/0004-6361/201834902
S2CID
85517040
Dones, Luke; Brasser, Ramon; Kaib, Nathan; Rickman, Hans (December 2015).
"Origin and Evolution of the Cometary Reservoirs"
Space Science Reviews
197
1–
4):
191–
269.
Bibcode
2015SSRv..197..191D
doi
10.1007/s11214-015-0223-2
ISSN
0038-6308
Brown, Michael E.; Trujillo, Chadwick; Rabinowitz, David (2004-12-10).
"Discovery of a Candidate Inner Oort Cloud Planetoid"
The Astrophysical Journal
617
(1):
645–
649.
arXiv
astro-ph/0404456
Bibcode
2004ApJ...617..645B
doi
10.1086/422095
ISSN
0004-637X
Trujillo, Chadwick A.; Sheppard, Scott S. (March 2014).
"A Sedna-like body with a perihelion of 80 astronomical units"
Nature
507
(7493):
471–
474.
Bibcode
2014Natur.507..471T
doi
10.1038/nature13156
ISSN
0028-0836
PMID
24670765
Witze, Alexandra (2014-03-26).
"Dwarf planet stretches Solar System's edge"
Nature
doi
10.1038/nature.2014.14921
ISSN
0028-0836
Brasser, R.; Schwamb, M. E. (2015-02-01).
"Re-assessing the formation of the inner Oort cloud in an embedded star cluster – II. Probing the inner edge"
Monthly Notices of the Royal Astronomical Society
446
(4):
3788–
3796.
arXiv
1411.1844
Bibcode
2015MNRAS.446.3788B
doi
10.1093/mnras/stu2374
ISSN
1365-2966
Chen, Ying-Tung; Kavelaars, J. J.; Gwyn, Stephen; Ferrarese, Laura; Côté, Patrick; Jordán, Andrés; Suc, Vincent; Cuillandre, Jean-Charles; Ip, Wing-Huen (2013-09-01).
"Discovery of a New Member of the Inner Oort Cloud from the Next Generation Virgo Cluster Survey"
The Astrophysical Journal
775
(1): L8.
arXiv
1308.6041
Bibcode
2013ApJ...775L...8C
doi
10.1088/2041-8205/775/1/L8
ISSN
0004-637X
Becker, A. C.; Arraki, K.; Kaib, N. A.; Wood-Vasey, W. M.; Aguilera, C.; Blackman, J. W.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Damke, G.; Davis, T. M.; Filippenko, A. V.; Foley, R. J.; Garg, A. (2008-07-20).
"Exploring the Outer Solar System with the ESSENCE Supernova Survey"
The Astrophysical Journal
682
(1):
L53–
L56.
arXiv
0805.4608
Bibcode
2008ApJ...682L..53B
doi
10.1086/590429
ISSN
0004-637X
Heisler, J.; Tremaine, S. (1986).
"The influence of the Galactic tidal field on the Oort comet cloud"
Icarus
65
(1):
13–
26.
Bibcode
1986Icar...65...13H
doi
10.1016/0019-1035(86)90060-6
Marc Fouchard; Christiane Froeschlé; Giovanni Valsecchi; Hans Rickman (2006). "Long-term effects of the galactic tide on cometary dynamics".
Celestial Mechanics and Dynamical Astronomy
95
1–
4):
299–
326.
Bibcode
2006CeMDA..95..299F
doi
10.1007/s10569-006-9027-8
S2CID
123126965
Higuchi A.; Kokubo E. & Mukai, T. (2005). "Orbital Evolution of Planetesimals by the Galactic Tide".
Bulletin of the American Astronomical Society
37
: 521.
Bibcode
2005DDA....36.0205H
Nurmi P.; Valtonen M.J.; Zheng J.Q. (2001).
"Periodic variation of Oort Cloud flux and cometary impacts on the Earth and Jupiter"
Monthly Notices of the Royal Astronomical Society
327
(4):
1367–
1376.
Bibcode
2001MNRAS.327.1367N
doi
10.1046/j.1365-8711.2001.04854.x
John J. Matese & Jack J. Lissauer (2004).
"Perihelion evolution of observed new comets implies the dominance of the galactic tide in making Oort Cloud comets discernible"
(PDF)
Icarus
170
(2):
508–
513.
Bibcode
2004Icar..170..508M
CiteSeerX
10.1.1.535.1013
doi
10.1016/j.icarus.2004.03.019
Archived
(PDF)
from the original on 2016-03-09
. Retrieved
2018-08-02
de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl; Aarseth, Sverre J. (2018).
"Where the Solar System meets the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies"
Monthly Notices of the Royal Astronomical Society: Letters
476
(1):
L1–
L5.
arXiv
1802.00778
doi
10.1093/mnrasl/sly019
Mamajek, Eric E.; Barenfeld, Scott A.; Ivanov, Valentin D. (2015).
"The Closest Known Flyby of a Star to the Solar System"
(PDF)
The Astrophysical Journal
800
(1): L17.
arXiv
1502.04655
Bibcode
2015ApJ...800L..17M
doi
10.1088/2041-8205/800/1/L17
S2CID
40618530
Archived
(PDF)
from the original on 2017-08-16
. Retrieved
2018-08-02
L. A. Molnar; R. L. Mutel (1997).
Close Approaches of Stars to the Oort Cloud: Algol and Gliese 710
. American Astronomical Society 191st meeting.
American Astronomical Society
Bibcode
1997AAS...191.6906M
A. Higuchi; E. Kokubo & T. Mukai (2006).
"Scattering of Planetesimals by a Planet: Formation of Comet Cloud Candidates"
Astronomical Journal
131
(2):
1119–
1129.
Bibcode
2006AJ....131.1119H
doi
10.1086/498892
Archived
from the original on 2020-10-01
. Retrieved
2019-08-25
Davis, M.; Hut, P.; Muller, R. A. (1984).
"Extinction of species by periodic comet showers"
Nature
308
(5954):
715–
717.
Bibcode
1984Natur.308..715D
doi
10.1038/308715a0
OSTI
1010922
J. G. Hills (1984). "Dynamical constraints on the mass and perihelion distance of Nemesis and the stability of its orbit".
Nature
311
(5987):
636–
638.
Bibcode
1984Natur.311..636H
doi
10.1038/311636a0
S2CID
4237439
"Nemesis is a myth"
. Max Planck Institute. 2011.
Archived
from the original on 2011-11-05
. Retrieved
2011-08-11
"Can WISE Find the Hypothetical 'Tyche'?"
. NASA/JPL. February 18, 2011.
Archived
from the original on 2020-12-05
. Retrieved
2011-06-15
John J. Matese & Jack J. Lissauer (2002-05-06).
"Continuing Evidence of an Impulsive Component of Oort Cloud Cometary Flux"
(PDF)
Proceedings of Asteroids, Comets, Meteors – ACM 2002. International Conference, 29 July – 2 August 2002, Berlin, Germany
Asteroids
. Vol. 500.
University of Louisiana at Lafayette
, and
NASA
Ames Research Center
. pp.
309–
314.
Bibcode
2002ESASP.500..309M
Archived
(PDF)
from the original on 2012-10-21
. Retrieved
2008-03-21
K. L., Luhman (7 March 2014). "A Search For A Distant Companion To The Sun With The Wide-field Infrared Survey Explorer".
The Astrophysical Journal
781
(1): 4.
Bibcode
2014ApJ...781....4L
doi
10.1088/0004-637X/781/1/4
S2CID
122930471
"It's Official: Voyager 1 Is Now In Interstellar Space"
UniverseToday
. 2013-09-12.
Archived
from the original on 2021-01-13
. Retrieved
April 27,
2014
Ghose, Tia (September 13, 2013).
"Voyager 1 Really Is In Interstellar Space: How NASA Knows"
Space.com
. TechMedia Network.
Archived
from the original on February 2, 2021
. Retrieved
September 14,
2013
Darling, David.
"TAU (Thousand Astronomical Unit) mission"
www.daviddarling.info
Archived
from the original on 2017-12-07
. Retrieved
2015-11-05
Matloff, Gregory L. (2005). "A probe to the Oort cloud".
Deep Space Probes: To the Outer Solar System and Beyond
(2nd ed.).
Chichester
Praxis Publishing
. p. 33.
ISBN
3-540-24772-6
Charles Alcock; et al.
"The Whipple Mission: Exploring the Oort Cloud and the Kuiper Belt"
(PDF)
. Archived from
the original
(PDF)
on 2015-11-17
. Retrieved
2015-11-12
"Scientific American – Kepler Spacecraft May Be Able to Spot Elusive Oort Cloud Objects – 2010"
Scientific American
Archived
from the original on 2020-12-18
. Retrieved
2015-11-05
Further reading
edit
Arnett, Bill (March 2007).
"The Kuiper Belt and The Oort Cloud"
Nine Planets
Brasser, R.; Schwamb, M. E. (2015).
"Re-assessing the formation of the inner Oort cloud in an embedded star cluster – II. Probing the inner edge"
Monthly Notices of the Royal Astronomical Society
446
(4): 3788.
arXiv
1411.1844
Bibcode
2015MNRAS.446.3788B
doi
10.1093/mnras/stu2374
S2CID
17001564
Batygin, Konstantin; Raush, Dennis (2024).
"Formation of the inner Oort cloud in the presence of an early solar binary"
Monthly Notices of the Royal Astronomical Society: Letters
533
(1):
L43–
L47.
arXiv
2305.00999
doi
10.1093/mnrasl/slad107
Fouchard, M.; Rickman, H.; Froeschlé, C.; Valsecchi, G. B. (2023).
"What long-period comets tell us about the Oort Cloud"
Astronomy & Astrophysics
671
: A36.
Bibcode
2023A&A...676A.104F
doi
10.1051/0004-6361/202243728
Hands, T. O.; Dehnen, W.; Gration, A. (2021).
"Formation of extrasolar Oort clouds and the origin of interstellar objects"
Astronomy & Astrophysics
647
: A96.
arXiv
2011.08257
doi
10.1051/0004-6361/202038888
Matthews, R. A. J. (1994). "The close approach of stars in the solar neighbourhood".
Quarterly Journal of the Royal Astronomical Society
35
: 1.
Bibcode
1994QJRAS..35....1M
Oort, Jan H. (1950).
"The structure of the cloud of comets surrounding the Solar System and a hypothesis concerning its origin"
Bulletin of the Astronomical Institutes of the Netherlands
11
91–
110.
Bibcode
1950BAN....11...91O
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Small Solar System bodies
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Former dwarf planets
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geology
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atmosphere?
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Candidate
(for TNOs,
D+1σ ≥ 700 km
or H ≤ 4.0)
Asteroids
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moon
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2003 VS
Classical
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Ilmarë
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Uni
Tinia
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moon?
2005 UQ
513
Other
resonances
2002 TC
302
moon?
2015 RR
245
2010 JO
179
2018 VG
18
'Farout'
Scattered disc
objects
Chiminigagua
moon
Gǃkúnǁʼhòmdímà
Gǃòʼé ǃHú
2014 UZ
224
'DeeDee'
2005 QU
182
Dziewanna
2010 KZ
39
2010 RF
43
2014 EZ
51
2017 OF
201
2021 DR
15
2021 LL
37
Sednoids
2012 VP
113
'Biden'
Category
Comets
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Latest
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C/2025 A6 (Lemmon)
C/2024 S1 (ATLAS)
C/2024 G3 (ATLAS)
C/2024 E1 (Wierzchoś)
C/2023 P1 (Nishimura)
C/2023 H2 (Lemmon)
C/2023 E1 (ATLAS)
C/2023 A3 (Tsuchinshan–ATLAS)
C/2022 E3 (ZTF)
C/2021 O3 (PanSTARRS)
C/2021 J1 (Maury–Attard)
C/2021 A1 (Leonard)
C/2020 S3 (Erasmus)
C/2020 X3 (SOHO)
C/2020 F8 (SWAN)
C/2020 F5 (MASTER)
C/2020 F3 (NEOWISE)
C/2019 Y4 (ATLAS)
C/2019 Y1 (ATLAS)
C/2019 U6 (Lemmon)
2I/Borisov
P/2019 LD2 (ATLAS)
Culture and
speculation
Antimatter comet
Comets in fiction
Comet vintages
Lists of comets
more
Periodic
comets
Until 1985
(all)
1P/Halley
2P/Encke
3D/Biela
4P/Faye
5D/Brorsen
6P/d'Arrest
7P/Pons–Winnecke
8P/Tuttle
9P/Tempel
10P/Tempel
11P/Tempel–Swift–LINEAR
12P/Pons–Brooks
13P/Olbers
14P/Wolf
15P/Finlay
16P/Brooks
17P/Holmes
18D/Perrine–Mrkos
19P/Borrelly
20D/Westphal
21P/Giacobini–Zinner
22P/Kopff
23P/Brorsen–Metcalf
24P/Schaumasse
25D/Neujmin
26P/Grigg–Skjellerup
27P/Crommelin
28P/Neujmin
29P/Schwassmann–Wachmann
30P/Reinmuth
31P/Schwassmann–Wachmann
32P/Comas Solà
33P/Daniel
34D/Gale
35P/Herschel–Rigollet
36P/Whipple
37P/Forbes
38P/Stephan–Oterma
39P/Oterma
40P/Väisälä
41P/Tuttle–Giacobini–Kresák
42P/Neujmin
43P/Wolf–Harrington
44P/Reinmuth
45P/Honda–Mrkos–Pajdušáková
46P/Wirtanen
47P/Ashbrook–Jackson
48P/Johnson
49P/Arend–Rigaux
50P/Arend
51P/Harrington
52P/Harrington–Abell
53P/Van Biesbroeck
54P/de Vico–Swift–NEAT
55P/Tempel–Tuttle
56P/Slaughter–Burnham
57P/du Toit–Neujmin–Delporte
58P/Jackson–Neujmin
59P/Kearns–Kwee
60P/Tsuchinshan
61P/Shajn–Schaldach
62P/Tsuchinshan
63P/Wild
64P/Swift–Gehrels
65P/Gunn
66P/du Toit
67P/Churyumov–Gerasimenko
68P/Klemola
69P/Taylor
70P/Kojima
71P/Clark
72P/Denning–Fujikawa
73P/Schwassmann–Wachmann
74P/Smirnova–Chernykh
75D/Kohoutek
76P/West–Kohoutek–Ikemura
77P/Longmore
78P/Gehrels
79P/du Toit–Hartley
80P/Peters–Hartley
81P/Wild
82P/Gehrels
83D/Russell
84P/Giclas
85D/Boethin
After 1985
(notable)
88P/Howell
92P/Sanguin
96P/Machholz
97P/Metcalf–Brewington
103P/Hartley
107P/Wilson–Harrington
108P/Ciffréo
109P/Swift–Tuttle
122P/de Vico
126P/IRAS
141P/Machholz
144P/Kushida
147P/Kushida–Muramatsu
153P/Ikeya–Zhang
156P/Russell–LINEAR
161P/Hartley–IRAS
162P/Siding Spring
168P/Hergenrother
169P/NEAT
177P/Barnard
178P/Hug–Bell
205P/Giacobini
209P/LINEAR
238P/Read
246P/NEAT
249P/LINEAR
252P/LINEAR
255P/Levy
273P/Pons–Gambart
289P/Blanpain
311P/PanSTARRS
322P/SOHO
323P/SOHO
332P/Ikeya–Murakami
333P/LINEAR
354P/LINEAR
362P
460P/PanSTARRS
Comet-like
asteroids
596 Scheila
2060 Chiron
(95P)
4015 Wilson–Harrington
(107P)
7968 Elst–Pizarro
(133P)
165P/LINEAR
166P/NEAT
167P/CINEOS
60558 Echeclus
(174P)
118401 LINEAR
(176P)
238P/Read
259P/Garradd
311P/PanSTARRS
324P/La Sagra
331P/Gibbs
354P/LINEAR
358P/PANSTARRS
P/2013 R3 (Catalina-PANSTARRS)
(300163) 2006 VW139
Lost
Recovered
9P/Tempel
11P/Tempel–Swift–LINEAR
15P/Finlay
17P/Holmes
27P/Crommelin
54P/de Vico–Swift–NEAT
55P/Tempel–Tuttle
57P/du Toit–Neujmin–Delporte
69P/Taylor
72P/Denning–Fujikawa
80P/Peters–Hartley
97P/Metcalf–Brewington
107P/Wilson–Harrington
113P/Spitaler
122P/de Vico
157P/Tritton
205P/Giacobini
206P/Barnard–Boattini
226P/Pigott–LINEAR–Kowalski
271P/van Houten–Lemmon
289P/Blanpain
489P/Denning
Destroyed
3D/Biela
D/1993 F2 (Shoemaker–Levy 9)
Not found
D/1770 L1 (Lexell)
5D/Brorsen
18D/Perrine–Mrkos
20D/Westphal
25D/Neujmin
34D/Gale
75D/Kohoutek
83D/Russell
85D/Boethin
D/1978 R1 (Haneda–Campos)
Visited by
spacecraft
21P/Giacobini–Zinner
(1985)
1P/Halley
(1986)
26P/Grigg–Skjellerup
(1992)
19P/Borrelly
(2001)
81P/Wild
(2004)
9P/Tempel
(2005, 2011)
C/2006 P1
(2007)
103P/Hartley
(2010)
67P/Churyumov–Gerasimenko
(2014)
Near-Parabolic
comets
(notable)
Until 1990
C/-43 K1 (Caesar's Comet)
X/1106 C1 (Great Comet of 1106)
C/1264 N1 (Great Comet of 1264)
C/1402 D1 (Great Comet of 1402)
C/1471 Y1 (Great Comet of 1472)
C/1577 V1 (Great Comet of 1577)
C/1652 Y1
C/1680 V1 (Great Comet of 1680, Kirsch's Comet, Newton's Comet)
C/1702 H1 (Comet of 1702)
C/1729 P1 (Comet of 1729, Comet Sarabat)
C/1739 K1 (Zanotti)
C/1743 X1 (Great Comet of 1744, Comet Klinkenberg-Chéseaux)
C/1760 A1 (Great Comet of 1760)
C/1769 P1 (Great Comet of 1769)
C/1807 R1 (Great Comet of 1807)
C/1811 F1 (Great Comet of 1811)
C/1819 N1 (Great Comet of 1819)
C/1823 Y1 (Great Comet of 1823)
C/1843 D1 (Great March Comet of 1843)
C/1846 J1 (Brorsen)
C/1847 T1 (Miss Mitchell's Comet)
C/1852 K1 (Chacornac)
C/1853 G1 (Schweizer)
C/1858 L1 (Comet Donati)
C/1861 G1 (Comet Thatcher)
C/1861 J1 (Great Comet of 1861)
C/1862 N1 (Schmidt)
C/1864 N1 (Tempel)
C/1865 B1 (Great Southern Comet of 1865)
X/1872 X1 (Pogson's Comet)
C/1874 H1 (Comet Coggia)
C/1881 K1 (Comet Tebbutt)
C/1882 R1 (Great Comet of 1882)
C/1887 B1 (Great Southern Comet of 1887)
C/1893 U1 (Brooks)
C/1901 G1 (Great Comet of 1901)
C/1907 G1 (Grigg–Mellish)
C/1910 A1 (Great January Comet of 1910)
C/1911 N1 (Kiess)
C/1911 O1 (Brooks)
C/1911 S3 (Beljawsky)
C/1915 C1 (Mellish)
C/1917 F1 (Mellish)
C/1927 X1 (Skjellerup–Maristany)
C/1931 P1 (Ryves)
C/1936 O1 (Kaho–Kozik–Lis)
C/1939 H1 (Jurlof–Achmarof–Hassel)
C/1941 B2 (de Kock-Paraskevopoulos)
C/1947 X1 (Southern Comet)
C/1948 L1 (Honda–Bernasconi)
C/1948 V1 (Eclipse)
C/1956 R1 (Arend–Roland)
C/1957 P1 (Mrkos)
C/1961 O1 (Wilson-Hubbard)
C/1961 R1 (Humason)
C/1961 T1 (Seki)
C/1962 C1 (Seki-Lines)
C/1963 A1 (Ikeya)
C/1963 R1 (Pereyra)
C/1964 N1 (Ikeya)
C/1965 S1 (Ikeya-Seki)
C/1969 T1 (Tago-Sato-Kosaka)
C/1969 Y1 (Bennett)
C/1970 K1 (White–Ortiz–Bolelli)
C/1973 E1 (Kohoutek)
C/1975 T2 (Suzuki–Saigusa–Mori)
C/1975 V1 (West)
C/1979 Y1 (Bradfield)
C/1980 E1 (Bowell)
C/1983 H1 (IRAS–Araki–Alcock)
C/1983 J1 (Sugano–Saigusa–Fujikawa)
C/1989 W1 (Aarseth-Brewington)
C/1989 X1 (Austin)
C/1989 Y1 (Skorichenko–George)
After 1990
C/1990 K1 (Levy)
C/1992 J1 (Spacewatch–Rabinowitz)
C/1993 Y1 (McNaught–Russell)
C/1995 O1 (Hale–Bopp)
C/1996 B2 (Hyakutake)
C/1997 L1 (Zhu–Balam)
C/1998 H1 (Stonehouse)
C/1998 J1 (SOHO)
C/1999 F1 (Catalina)
C/1999 H1 (Lee)
C/1999 S4 (LINEAR)
C/2000 WM1 (LINEAR)
C/2001 A2 (LINEAR)
C/2001 OG108 (LONEOS)
C/2001 Q4 (NEAT)
C/2002 T7 (LINEAR)
C/2002 V1 (NEAT)
C/2004 F4 (Bradfield)
C/2004 Q2 (Machholz)
C/2006 A1 (Pojmański)
C/2006 M4 (SWAN)
C/2006 P1 (McNaught)
C/2007 E2 (Lovejoy)
C/2007 F1 (LONEOS)
C/2007 N3 (Lulin)
C/2007 Q3 (Siding Spring)
C/2007 W1 (Boattini)
C/2009 F6 (Yi–SWAN)
C/2009 R1 (McNaught)
C/2010 X1 (Elenin)
C/2011 L4 (PANSTARRS)
C/2011 W3 (Lovejoy)
C/2012 E2 (SWAN)
C/2012 F6 (Lemmon)
C/2012 K1 (PANSTARRS)
C/2012 S1 (ISON)
C/2013 A1 (Siding Spring)
C/2013 R1 (Lovejoy)
C/2013 US10 (Catalina)
C/2013 V5 (Oukaimeden)
C/2014 E2 (Jacques)
C/2014 Q1 (PanSTARRS)
C/2014 Q2 (Lovejoy)
C/2014 UN271 (Bernardinelli–Bernstein)
C/2015 ER61 (PanSTARRS)
C/2015 V2 (Johnson)
C/2017 K2 (PanSTARRS)
1I/2017 U1 ʻOumuamua
C/2018 Y1 (Iwamoto)
2I/Borisov
C/2019 U6 (Lemmon)
C/2019 Y4 (ATLAS)
C/2020 F3 (NEOWISE)
C/2020 F8 (SWAN)
C/2021 A1 (Leonard)
C/2022 E3 (ZTF)
C/2023 A3 (Tsuchinshan–ATLAS)
C/2023 P1 (Nishimura)
C/2024 G3 (ATLAS)
C/2024 S1 (ATLAS)
C/2025 A6 (Lemmon)
C/2025 D1 (Gröller)
After 1910
(by name)
Aarseth–Brewington
Arend–Roland
ATLAS
C/2019 Y4
C/2024 G3
C/2024 S1
3I
Austin
Beljawsky
Bennett
Bernardinelli–Bernstein
Boattini
Borisov
Bowell
Bradfield
C/1979 Y1
C/2004 F4
Brooks
Catalina
C/1999 F1
C/2013 US10
de Kock–Paraskevopoulos
Eclipse
Elenin
Gröller
Hale-Bopp
Honda–Bernasconi
Humason
Hyakutake
Ikeya
C/1963 A1
C/1964 N1
Ikeya-Seki
IRAS–Araki–Alcock
ISON
Iwamoto
Jacques
Johnson
Jurlof–Achmarof–Hassel
Kaho–Kozik–Lis
Kiess
Kohoutek
Lee
Lemmon
C/2012 F6
C/2019 U6
C/2025 A6
Leonard
Levy
LINEAR
C/1999 S4
C/2000 WM1
C/2001 A2
C/2002 T7
LONEOS
C/2001 OG108
C/2007 F1
Lovejoy
C/2007 E2
C/2011 W3
C/2013 R1
C/2014 Q2
Lulin
Machholz
McNaught
C/2006 P1
C/2009 R1
McNaught–Russell
Mellish
C/1915 C1
C/1917 F1
Mrkos
NEAT
C/2001 Q4
C/2002 V1
NEOWISE
Nishimura
Oukaimeden
ʻOumuamua
Pan-STARRS
C/2011 L4
C/2012 K1
311P/PanSTARRS
C/2014 Q1
C/2015 ER61
C/2017 K2
Pereyra
Pojmański
Ryves
Seki
Seki–Lines
Siding Spring
C/2007 Q3
C/2013 A1
Skjellerup–Maristany
Skorichenko–George
SOHO
Solwind
Southern
Spacewatch
Stonehouse
Sugano–Saigusa–Fujikawa
Suzuki–Saigusa–Mori
SWAN
C/2006 M4
C/2020 F8
Tago–Sato–Kosaka
Tsuchinshan–ATLAS
West
White–Ortiz–Bolelli
Wilson–Hubbard
Yi–SWAN
Zhu–Balam
ZTF
Category
Authority control databases
International
VIAF
FAST
National
United States
Israel
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