2MASS J11151597+1937266 (also called 2MASS J1115+1937) is a young isolated planetary-mass object that is surrounded by a planetary disk. 2MASS J1115+1937 was discovered in 2017 in the LaTE-MoVeRS survey (Late-Type Extension to the Motion Verified Red Stars), which combined

2MASS The Two Micron All-Sky Survey, or 2MASS, was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and ...

, SDSS and WISE data to search for faint moving stars. The spectral fit showed that it is an

L dwarf An object with the spectral type L (also called L-dwarf) can be either a low-mass star, a brown dwarf or a young rogue planet, free-floating planetary-mass object. If a young exoplanet or planetary-mass companion is detected via direct imaging, it ...

, with low

gravity In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

. A spectral type of L2γ was assigned for 2MASS J1115+1937. This work did not find a match with any known

stellar associations A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more visible stars. An association is primarily identified by commonalities in i ...

and suggested it might have been ejected from such an association in the past. Infrared spectroscopy from the

NASA Infrared Telescope Facility The NASA Infrared Telescope Facility (NASA IRTF) is a telescope optimized for use in infrared astronomy and located at the Mauna Kea Observatory in Hawaii. It was first built to support the Voyager program, Voyager missions and is now the US n ...

was published in 2018. This team found a spectral type of L2γ (±1) and an age of 5–45 Million years (Myr). The upper age limit is determined by the maximum age at which low-mass stars accrete material (see

Peter Pan disk A Peter Pan disk is a circumstellar disk around a star or brown dwarf that appears to have retained enough gas to form a gas giant planet for much longer than the typically assumed gas dispersal timescale of approximately 5 million years. Several ...

), but 2MASS J1115+1937 could be younger than this upper limit. Using this age range the team found a mass range of 7 to 21 . Additional follow-up was presented in 2024 with the

Very Large Telescope The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with ...

(VLT), UVES instrument. The mass remains uncertain, but using the pre-shock velocity ( km/s) the team found a mass of . The near-infrared spectrum shows

water vapor Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from th ...

(H₂O),

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

(CO),

iron hydride An iron hydride is a chemical system which contains iron and hydrogen in some associated form. Because of the common occurrence of those two element (chemistry), elements in the universe, possible compounds of hydrogen and iron have attracted at ...

(FeH),

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

(Na) and

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

(K). The optical spectrum shows hydrogen and helium emission. It also shows possibly metal absorption lines of

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

(Ca),

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

(Fe),

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

(Ti) and

chromium Chromium is a chemical element; it has Symbol (chemistry), symbol Cr and atomic number 24. It is the first element in Group 6 element, group 6. It is a steely-grey, Luster (mineralogy), lustrous, hard, and brittle transition metal. Chromium ...

(Cr).

The accretion disk

The discovery team showed that the SDSS spectrum contained a number of

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

emission lines and the

H-alpha Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is em ...

emission line was broadened, showing signs of

accretion Accretion may refer to: Science * Accretion (astrophysics), the formation of planets and other bodies by collection of material through gravity * Accretion (meteorology), the process by which water vapor in clouds forms water droplets around nucl ...

. The team found that the neutral potassium line was weaker than other low gravity dwarfs, which is seen as either an even lower gravity or material blocking this part of the atmosphere. Additionally a higher than normal WISE W3 (about 10 μm) flux indicates the presence of dust around the object. In a follow-up paper, the team interpreted the hydrogen emission as either

magnetic Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, m ...

activity and/or weak accretion. The team also found emission due to neutral

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

(He), which is another sign of accretion. Observations with the VLT confirmed the ongoing accretion and the infrared excess. The team identified additional hydrogen emission lines and found asymmetric line profiles. The H-alpha flux decreased by about 7% between 2007 and 2012, and then increased by about 20% between 2012 and 2023. This is seen as a variable accretion rate. The mass accretion rate was estimated to be × 10⁻⁸ /year (about the mass of

3 Juno Juno (minor-planet designation: 3 Juno) is a large asteroid in the asteroid belt. Juno was the third asteroid discovered, in 1804, by German astronomer Karl Harding. It is tied with three other asteroids as the thirteenth largest asteroid, and ...

per year).

Ruled out stellar companion

It was suggested that 2MASS J1115+1937 co-moves with 2MASS J11131089+2110086 (2MASS J1113+2110) based on similar

proper motion Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...

and

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

. Due to newly released

Gaia In Greek mythology, Gaia (; , a poetic form of ('), meaning 'land' or 'earth'),, , . also spelled Gaea (), is the personification of Earth. Gaia is the ancestral mother—sometimes parthenogenic—of all life. She is the mother of Uranus (S ...

astrometry, especially the difference in

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

, another team ruled out that the two 2MASS objects are a physical pair. The team does however consider it possible that the pair has a similar dynamical origin. Maybe the two objects belong to an unknown stellar group.

References

{{reflist , refs= {{cite Gaia EDR3, 3990192705824438144 {{Cite journal , last1=Theissen , first1=Christopher A. , last2=West , first2=Andrew A. , last3=Shippee , first3=Guillaume , last4=Burgasser , first4=Adam J. , last5=Schmidt , first5=Sarah J. , date=2017-03-01 , title=The Late-Type Extension to MoVeRS (LaTE-MoVeRS): Proper Motion Verified Low-mass Stars and Brown Dwarfs from SDSS, 2MASS, and WISE , journal=The Astronomical Journal , volume=153 , issue=3 , pages=92 , arxiv=1612.05252 , bibcode=2017AJ....153...92T , doi=10.3847/1538-3881/153/3/92 , doi-access=free , issn=0004-6256 {{Cite journal , last1=Theissen , first1=Christopher A. , last2=Burgasser , first2=Adam J. , last3=Bardalez Gagliuffi , first3=Daniella C. , last4=Hardegree-Ullman , first4=Kevin K. , last5=Gagné , first5=Jonathan , last6=Schmidt , first6=Sarah J. , last7=West , first7=Andrew A. , date=2018-01-01 , title=2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-mass Object with a Potential Wide Stellar Companion , journal=The Astrophysical Journal , volume=853 , issue=1 , pages=75 , arxiv=1712.03964 , bibcode=2018ApJ...853...75T , doi=10.3847/1538-4357/aaa0cf , doi-access=free , issn=0004-637X {{Cite arXiv , last1=Viswanath , first1=Gayathri , title=Exoplanet accretion monitoring spectroscopic survey (ENTROPY) I. Evidence for magnetospheric accretion in the young isolated planetary-mass object 2MASS J11151597+1937266 , date=2024-09-01 , eprint=2409.12187 , class=astro-ph , last2=Ringqvist , first2=Simon C. , last3=Demars , first3=Dorian , last4=Janson , first4=Markus , last5=Bonnefoy , first5=Mickaël , last6=Aoyama , first6=Yuhiko , last7=Marleau , first7=Gabriel-Dominique , last8=Dougados , first8=Catherine , last9=Szulágyi , first9=Judit Rogue planets L-type brown dwarfs Leo (constellation) Circumstellar disks

The accretion disk

Ruled out stellar companion

See also

References