COCONUTS-2 b, or WISEPA J075108.79-763449.6, is a
gas giant
A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...
exoplanet that orbits the
M-type star
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...
L 34-26. With a mass of 6.3
Jupiters
The Jupiters () were a Pakistani music band who are considered one of the pioneers of pop music in Pakistan. Although the band released only a few albums, it became a breeding ground for many notable future singers. The hit song "Yaaro Yehi Dosti ...
, it takes over one million years to complete one orbit around the star, and it is 6000
AU away from it.
The planet was discovered in 2011 and was initially identified as a T9 free-floating
brown dwarf
Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...
WISEPA J075108.79−763449.6.
During the
COol Companions ON Ultrawide orbiTS (COCONUTS) survey, its association with L 34-26 was announced in 2021. At a distance of 10.9 pc, COCONUTS-2b is the closest
directly imaged exoplanet to Earth known to date.
The researchers found that it is unlikely that COCONUTS-2b was formed inside the
protoplanetary disk
A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may also be considered an accretion disk for the star itself, be ...
of the host star and it is more likely that the planet formed on its own via high
entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
formation (aka hot-start process).
Atmosphere
The planet has a spectral type of T9, based on a low Signal-to-noise ratio, signal-to-noise Near-infrared spectroscopy, near-infrared spectrum with Magellan Telescopes, Magellan/FIRE.
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 Cloud, clouds and a Brown dwarf#Role of vertical mixing, non-equilibrium process in its atmosphere.
Due to its large orbital separation, COCONUTS-2b is a great laboratory to study the atmosphere and composition of young gas-giant exoplanets.
Astronomers estimate the planet’s temperature to be around .
Host star
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.
Researchers using Transiting Exoplanet Survey Satellite, TESS found that L 34-26 showed Solar flare, 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.
Gallery
File:COCONUTS-2 system unWISE.png, The COCONUTS-2 system with Wide-field_Infrared_Survey_Explorer#unWISE_and_CatWISE, unWISE
File:COCONUTS-2b Gemini JHK.png, The planet COCONUTS-2b with Gemini Observatory, Gemini-South
File:COCONUTS-2b.jpg, Wide-field_Infrared_Survey_Explorer, Allwise image by the discoverers, showing planet COCONUTS-2b
References
{{2021 in space
Exoplanets discovered in 2021
Exoplanets detected by direct imaging
Gas giants