Loading AI tools
Gas giant exoplanet orbiting L 34-26 From Wikipedia, the free encyclopedia
COCONUTS-2 b, or WISEPA J075108.79-763449.6, is a gas giant exoplanet that orbits the M-type star L 34-26. With a mass of 6.3 Jupiters, it takes over one million years to complete one orbit around the star orbiting 7,506 AU away from it.[1]
Discovery | |
---|---|
Discovered by | Zhoujian Zhang Michael Liu Zach Claytor William Best Trent Dupuy Robert Siverd[1] |
Discovery date | August 2011[2] July 2021[3] |
Direct imaging | |
Designations | |
WISEPA J075108.79-763449.6[2] | |
Orbital characteristics | |
7,506.0 AU (1.12288×1012 km)[4] or ~0.1185 ly (~0.03633 pc) | |
1101369.9 years[4] | |
Star | L 34-26 |
Physical characteristics | |
1.12±0.04 RJ[5] | |
Mass | 6.3+1.5 −1.9 MJ[6][4] |
4.11+0.11 −0.18 dex[6] | |
Temperature | 434 ± 9 K[6] |
Spectral type | T9 |
The planet was discovered in 2011 and was initially identified as a T9 free-floating brown dwarf WISEPA J075108.79−763449.6.[2] During the COol Companions ON Ultrawide orbiTS (COCONUTS) survey, its association with L 34-26 was announced in 2021.[7] At a distance of 35.5 light-years (10.9 parsecs), COCONUTS-2b was the closest directly imaged exoplanet to Earth[8] until Epsilon Indi Ab was imaged in 2024.
The researchers found that it is unlikely that COCONUTS-2b was formed inside the protoplanetary disk of the host star and it is more likely that the planet formed on its own via high entropy formation (aka hot-start process).[6][9]
The peculiar properties of COCONUTS-2b could be explained with different scenarios as proposed by Marocco et al. in 2024. The properties could be explained by a non-solar carbon-to-oxygen ratio, meaning that it formed inside a disk around L 34-26. In this scenario the most likely way COCONUTS-2b got in a higher orbit is by a stellar fly-by of two binaries or two planetary systems. In the second scenario L 34-26 is not actually young, but mimics youth due to tidal and/or magnetic interactions with an unseen companion. In this scenario COCONUTS-2b would be an old brown dwarf. In a third scenario COCONUTS-2b could be a captured old brown dwarf. This is however seen as unlikely due to the stellar fly-by requiring a low velocity.[10]
The planet has a spectral type of T9, based on a low signal-to-noise near-infrared spectrum with Magellan/FIRE.[2][6] This spectral type suggests high amounts of methane, water vapor and low amounts of carbon monoxide in the atmosphere of COCONUTS-2b.
COCONUTS-2b might have both clouds and a non-equilibrium process in its atmosphere.[6]
Due to its large orbital separation, COCONUTS-2b is a great laboratory to study the atmosphere and composition of young gas-giant exoplanets.[3] Astronomers estimate the planet’s temperature to be around 434 K (161 °C; 322 °F).[6]
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Chamaeleon |
Right ascension | 07h 49m 12.678s[11] |
Declination | −76° 42′ 06.72″[11] |
Apparent magnitude (V) | 11.3[12] |
Characteristics | |
Evolutionary stage | Red dwarf |
Spectral type | M3V[12] |
Astrometry | |
Radial velocity (Rv) | 1.19±0.61[13] km/s |
Proper motion (μ) | RA: -102.154 mas/yr[11] Dec.: -192.918 mas/yr[11] |
Parallax (π) | 91.8263 ± 0.0185 mas[11] |
Distance | 35.519 ± 0.007 ly (10.890 ± 0.002 pc) |
Details | |
Mass | 0.37±0.02[6] M☉ |
Radius | 0.388±0.11[6] R☉ |
Temperature | 3,406±69[6] K |
Age | 150–800[6] Myr |
Other designations | |
L 34-26, COCONUTS-2A, WISEPA J075108.79-763449.6, 1RXS J074912.9-764202, 2MASS J07491271-7642065, ASAS J074912-7641.9, Gaia DR1 5213167326052013184, Gaia DR2 5213167330349528064, Gaia DR3 5213167330349528064, NLTT 18592
PM J07492-7642, RAVE J074912.7-764207, TIC 272232401, TYC 9381-1809-1, UCAC4 067-006518, USNO-B1.0 0132-00043434 | |
Database references | |
SIMBAD | data |
L 34-26, also known as COCONUTS-2A and TYC 9381-1809-1, is a M3-type dwarf star located 35 light-years away, in the constellation of Chamaeleon. The star is about one-third the mass of the Sun, with an age between 150 and 800 million years old.[14]
Researchers using TESS found that L 34-26 showed stellar flares about every 0.48 days. It was the most active planet hosting star in their sample. The team studying the host star also found that L 34-26 is fast rotating with a rotation period of 2.83 days. The planet should not be influenced by the flares, because of the large orbital separation.[15] The star is seen almost equator-on with i = 81.8±5.8 deg and might belong to the proposed Ursa Major corona, which is 400 million years old.[10]
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.