 2MASS J0249−0557 AB and its companion Credit:Legacy Surveys / D. Lang (Perimeter Institute) & Meli_thev | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Eridanus[1] |
| Right ascension | 02h 49m 56.39s |
| Declination | −05° 57′ 35.4″ |
| Characteristics | |
| Evolutionary stage | brown dwarf |
| Spectral type | M6+L2[2] |
| Astrometry | |
| Radial velocity (Rv) | 14.42 ±0.44[3] km/s |
| Proper motion (μ) | RA: 48.795 ±0.067mas/yr[4] Dec.: –35.211 ±0.057mas/yr[4] |
| Parallax (π) | 15.0946±0.057 mas[4] |
| Distance | 216.1 ± 0.8 ly (66.2 ± 0.3 pc) |
| Details[2] | |
| 2MASS J0249−0557 A | |
| Mass | 48+13 −12 MJup |
| Luminosity (bolometric) | 10–2.59 ±0.09 L☉ |
| 2MASS J0249−0557 B | |
| Mass | 44+14 −11 MJup |
| Luminosity (bolometric) | 10–2.64 ±0.09 L☉ |
| Position (relative to 2MASS J0249−0557 A)[2] | |
| Component | 2MASS J0249−0557 B |
| Angular distance | 0.0444 ±0.0002″ |
| Position angle | 233.1 ±0.3° |
| Projected separation | 2.17 ±0.22AU |
| Other designations | |
| 2MASS J02495639−0557352,SDSS J024956.41−055735.7,TIC 10930507,Gaia DR2 5183875103632956032 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
2MASS J0249−0557 (also known as2MASS J02495639−0557352) is a young low-massbinary brown dwarf in thebeta Pictoris moving group. It has onecircumbinary planetary-mass companion, called 2MASS J0249−0557 (AB)c, or just 2MASS J0249−0557 c.[2]
The host was discovered as a member of the 22 ±6 Myr old beta Pictoris moving group in 2017 and a spectrum shows a spectral type of M6 with very low gravity.[3]Keck Observatory adaptive optics aperture-masking interferometry showed that the primary 2MASS J0249−0557 is a binary. The binary is separated by 2.17 ±0.22AU. 2MASS J0249−0557A has a mass of48+13
−12MJ and 2MASS J0249−0557B has a mass of44+14
−11MJ, making the host a binary of two brown dwarfs.[2]
The companion 2MASS J0249−0557 c (also known as 2MASS J02495436−0558015) was discovered in 2018 using astrometry from theCanada–France–Hawaii Telescope as a wide-separation companion, with a separation of 1950 ± 200 AU. Two near-infrared spectra were obtained. One fromIRTF and the other fromAPO. A spectral type ofL2 ±1 was assigned. Several spectral features show a lowgravity, such as strongerVO and weakerFeH. The mass of the companion was estimated to be11.6+1.3
−1.0MJ, below thedeuterium burning limit. The mass ration between companion and host binary is relative high (Mcomp/Mhost≥0.1), suggesting the system formed like astellar triple. Unusual is the large separation of 2MASS J0249−0557 c. This could mean that it formed closer to the binary and was affected by turbulent fragmentation, which can lead to wide separations. A disfavoured alternative is that it formed in a disk around the binary and was scattered via dynamical interaction.[2] Optical and near-infrared spectroscopy was obtained with theGran Telescopio Canarias and theNew Technology Telescope. This team also found evidence for low gravity in the form of strong absorption by oxides and weak absorption byalkali metals. Additionally the optical spectrum showed strongHydrogen-alpha emission. This could indicate strongchromospheric activity oraccretion from a disk around 2MASS J0249−0557 c. Strong H-alpha emission is more common in late M-dwarfs, but rare in young L-dwarfs. Other examples of L-dwarfs with strong H-alpha emission are2MASS J11151597+1937266 andDelorme 1 (AB)b.[5]
