List of extrasolar planetary collisions

This is a list of collisions between exoplanets or planetesimals observed in extrasolar systems. These collisions are more common in young systems and are an important part in the growth of especially terrestrial planets from so-called planetary embryos.^[1] Detections of individual collisions are nevertheless rare and are detected via transits in the optical, infrared excess, silicate emission or via infrared brightening. Collisions are thought to be common in a type of debris disk, so-called extreme debris disks (EDD). Co-moving stellar or substellar companions can trigger such collisions at an old age, creating old EDDs. Only about 24 EDDs are known.^[2][3]

Artist's impression of a collision in NGC 2547–ID8

Fading and expansion of the Fomalhaut b dust cloud

This list does not include planetary bodies being accreted by white dwarfs, for this refer to the List of exoplanets and planetary debris around white dwarfs.

List of individual events

This list contains systems with individual collision events that were directly observed. Alternatively events were inferred from properties of the disk. The list is sorted after the start of the event.^{[clarification needed]}

Name of star	spectral type	Approx. age (Myr)	Extreme debris disk?	Start of event	Colliding bodies	Notes	Ref.
Beta Pictoris	A6V	20	no	~150 years ago	100–500 km body	So-called "cat's tail" feature in the disk observed in mid-infrared	[4]
				A few years before 2004		Decreased mid-infrared flux and disappearance of forsterite emission	[5]
Fomalhaut	A3V	440	no	Early 2004	Two bodies of ≥110 km in size, or a 56 km body impacting a 893 km body	Fomalhaut b was once suspected to be a planet, but is now suspected to be the remains of a planetary collision	[6]
P1121	F9V	80	yes[3]	Before 2012	Two bodies with sizes of ≥100 km	One hypervelocity impact	[2][7]
NGC 2547–ID8	G6V	35	yes[3]	late 2012	Two bodies with sizes of ≥100 km	likely grazing or hit-and-run type event	[7][8]
				early 2014	100 km bodies, maybe same objects as the first event	fragments dominated by boulders	[7]
HD 169142	A5V	6	no	2013–2018	Unknown	Variability interpreted as appearance and disappearance of a dust ring. Comparisons with EDDs were made.	[9]
TYC 4209-1322-1	G1V	275	yes[3]	2010 or earlier	unknown		[10]
				Sometime in 2014	Two ≥90 km bodies	brightening and fading between 2014 and 2018	[11][10]
HD 166191	late F- to early G	10	yes[3]	Early 2018	Two ≥500 km bodies	Sudden increase of dust production in early 2018, reaching a high in 2019. Also transit of star-sized dust clouds, produced by the collisions.	[12]
V488 Persei	K2-2.5 V	80	yes[3]	2019	Two 60 km bodies	Constant collisions will last 1,000 to 10,000 years. Possibly formation of a Mercury-like planet.	[13][14]
ASASSN-21qj	G2	300	no?	December 2021	Two ice giants	Breakup of exocomets was also proposed.[15]	[16]
HD 172555	A5V	23	no	Within 0.1 Myr	Two planetesimals	Compared to the formation of the Moon	[17][18]
BD+20 307	F-type binary	≥1000	yes[3]	Unknown	Planetary-scale	Catastrophic collision between planetary-scale bodies	[19][20]
HD 15407A	F3V	80 or 2100	yes[3]	Unknown	Planetesimals?	One giant hypervelocity impact?	[21][22]
HD 23514	F6V	100	yes[3]	Unknown	Planetary embryos	Member of the Pleiades	[23]
TYC 4479-3-1	G6V	5000	yes[3]	Unknown	≥50 km planetesimal	Disruption of one body	[11]
HD 113766A	F2V	17	yes[3]	Unknown	Partially differentiated bodies	Recent impact of two asteroids or planetary bodies	[24][25]
TYC 8830-410-1	G9V	600	yes[3]	Unknown	Rocky bodies	Giant impact	[26]

List of other EDDs

These objects appear as EDDs in Moór et al.^[3] EDDs are listed here, because they are often associated with individual giant collisions. List is sorted after discovery year.

Name of star	Spectral type	Approx. age (Myr)	Notes	Discovery year[3]	Ref.
TYC 8241–2652–1	K2	10	rapid disappearance of the disk, unknown mechanism	2012	[27][28]
RZ Piscium	K0IV	30	Intense continuous collisions, destroying a 90 km asteroid each year.	2013	[29][30]
TIC 43488669		100-400	runaway star, without further estimates of the collisions	2020	[31]
TYC 4515–485–1	F5V	>150	without further estimates of the collisions	2021	[11]
TYC 5940–1510–1	G5V	120	without further estimates of the collisions	2021	[11]
TYC 8105–370–1	G9V	130	without further estimates of the collisions	2021	[11]
BD-04 3234 (TYC 4946–1106–1)	F6V	>150	without further estimates of the collisions	2021	[11]
TYC 9196-2916-1	K4.5V	85	without further estimates of the collisions	2022	[32][3]
2MASS J06091701-1508085	G9V	200	without further estimates of the collisions	2024	[3]
2MASS J07120655-4752423	K3.5V	240	without further estimates of the collisions	2024	[3]
CD-44 6765	K0.5V	5500	without further estimates of the collisions	2024	[3]
2MASS J20431522+1043355	K4V	250	without further estimates of the collisions	2024	[3]

List of EDD without collisions

Name of star	spectral type	approximate age (Myr)	notes	discovery year[3]	Reference
HD 145263	F4V	11	hypervelocity impact was excluded in one study, instead extreme space weathering was suggested to explain observed mineralogy.[33] This object appears as an EDD in Moór et al.[3]	1998	[33]

See also

• List of stars that have unusual dimming periods
• List of largest craters in the Solar System
• Giant impact hypothesis
• Mercury (planet) is thought to have lost its mantle from a collision
• 354P/LINEAR small asteroid that was impacted by another asteroid