2M1510

2MASS J15104761–2818234, sometimes shortened to 2M1510, is a triple or possibly quadruple brown dwarf system, consisting of the eclipsing binary 2M1510A and the wide companion 2M1510B.[1] 2M1510A was found to be an eclipsing binary in the first light data of the SPECULOOS telescopes. It is only the second eclipsing binary brown dwarf found so far (as of March 2020), the other is 2M0535-05. The system verified theoretical models for how brown dwarfs cool. The system is located 120 light-years away from earth in the constellation Libra.[5]

2M1510

A light curve for 2M1510, adapted from Triaud et al. (2020)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
2M1510 A
Right ascension 15h 10m 47.86s[2]
Declination −28° 18′ 17.5″[2]
2M1510 B
Right ascension 15h 10m 47.60s[3]
Declination −28° 18′ 23.4″[3]
Characteristics
2M1510 A
Spectral type M9γ + L1β(?) (near-IR)[1][4]
Apparent magnitude (G) 17.487[2]
Variable type eclipsing[1]
2M1510 B
Spectral type M9γ (near-IR)[1]
Apparent magnitude (G) 18.886[3]
Astrometry
2M1510 A
Radial velocity (Rv)-12.9 ± 0.4[1] km/s
Proper motion (μ) RA: −118.747±0.492[2] mas/yr
Dec.: −46.865±0.420[2] mas/yr
Parallax (π)27.2203 ± 0.2665 mas[2]
Distance120 ± 1 ly
(36.7 ± 0.4 pc)
2M1510 B
Radial velocity (Rv)-12.0 ± 0.3[1] km/s
Proper motion (μ) RA: −117.458±0.893[3] mas/yr
Dec.: −45.713±0.746[3] mas/yr
Parallax (π)27.6869 ± 0.4939 mas[3]
Distance118 ± 2 ly
(36.1 ± 0.6 pc)
Orbit[1]
Primary2M1510 Aa
Companion2M1510 Ab
Period (P)20.9022+0.0059
−0.0056 days
Semi-major axis (a)0.0627 ± 0.0014 au
Eccentricity (e)0.309 ± 0.022
Inclination (i)88.5 ± 0.1°
Details[1]
2M1510 Aa
Mass0.0382+0.0028
−0.0026 M☉
Radius1.575 RJup
Luminosity0.00063±0.00001 L☉
Surface gravity (log g)4.55 cgs
Temperature2,400 K
Rotational velocity (v sin i)8.7±1.0 km/s
Age45 ± 5 Myr
2M1510 Ab
Mass0.0375+0.0029
−0.0028 M☉
Radius1.575 RJup
Luminosity0.00063±0.00001 L☉
Surface gravity (log g)4.55 cgs
Temperature2,400 K
Metallicity [Fe/H]0.0 dex
Rotational velocity (v sin i)6.8±1.5 km/s
Age45±5 Myr
Other designations
2M1510 AB, 2MASSW J1510478–281817, 2MASS J15104761–2818234, DENIS J151047.8–281817, 2MUCD 20604, Gaia DR2 6212595980928732032
Database references
SIMBADA
B

Signs of youth

2M1510A has hydrogen-alpha emission lines, which is interpreted as a sign of youth.[6] The system also belongs to the 45±5 million-year-old Argus moving group[7] and the brown dwarfs have a low surface gravity, which is an additional indicator for youth.[1]

The brown dwarf system

2M1510A and 2M1510B are separated by 250 astronomical units, making them a resolved binary in 2MASS data. The components of the inner eclipsing binary are called 2M1510Aa and 2M1510Ab. Despite the small letter used in this configuration these objects are not planets, but brown dwarfs that burn deuterium. 2M1510A is not only an eclipsing binary, but also a double-lined spectroscopic binary. This was discovered by follow-up observations with Keck II. Follow-up observations with Keck II and the VLT UT2 showed that 2M1510Aa and 2M1510Ab have very similar masses, something that is called a near equal-mass binary. 2M1510Aa has a mass of about 40 MJ and 2M1510Ab has a mass of about 39 MJ. The pair orbits each other every 20.9 days.[1] Additionally the 2M1510A source has an elongated point spread function in VLT/SINFONI data. The naming of the brown dwarfs in Calissendorff et al. 2019 does not follow other works and the companion was called 2M1510B (here from now on: 2M1510B'). 2M1510B' has a mass of 17.68+4.20
−2.10 MJ and it is separated by about 4.4 au from 2M1510A and orbits the eclipsing binary each 30 years.[4] This result was not considered by Triaud et al. 2020 and it could represent a contamination of the eclipsing binary, making a test of the cooling models more challenging.

See also

References
  1. Triaud, Amaury H. M. J.; Burgasser, Adam J.; Burdanov, Artem; Kunovac Hodžić, Vedad; Alonso, Roi; Bardalez Gagliuffi, Daniella; Delrez, Laetitia; Demory, Brice-Olivier; de Wit, Julien; Ducrot, Elsa; Hessman, Frederic V. (January 2020). "An Eclipsing Substellar Binary in a Young Triple System discovered by SPECULOOS". Nature Astronomy. 4 (7): 650–657. arXiv:2001.07175. Bibcode:2020NatAs...4..650T. doi:10.1038/s41550-020-1018-2. S2CID 210839528.
  2. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  3. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  4. Calissendorff, Per; Janson, Markus; Asensio-Torres, Rubén; Köhler, Rainer (July 2019). "Spectral characterization of newly detected young substellar binaries with SINFONI". Astronomy & Astrophysics. 627: A167. arXiv:1906.05871. Bibcode:2019A&A...627A.167C. doi:10.1051/0004-6361/201935319. ISSN 0004-6361. S2CID 189898015.
  5. "Astronomers Catch Rare Eclipse of a Double Brown Dwarf System – W. M. Keck Observatory". Retrieved 2020-03-10.
  6. Gizis, John E. (August 2002). "Brown Dwarfs and the TW Hydrae Association". The Astrophysical Journal. 575 (1): 484–492. arXiv:astro-ph/0204342. Bibcode:2002ApJ...575..484G. doi:10.1086/341259. ISSN 0004-637X. S2CID 119091936.
  7. Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle L.; Lafreniére, David; Doyon, René; Malo, Lison; Burgasser, Adam J.; Naud, Marie-Eve; Artigau, Étienne; Bouchard, Sandie; Gizis, John E. (August 2015). "BANYAN. VII. A New Population of Young Substellar Candidate Members of Nearby Moving Groups from the BASS Survey". The Astrophysical Journal Supplement Series. 219 (2): 33. arXiv:1506.07712. Bibcode:2015ApJS..219...33G. doi:10.1088/0067-0049/219/2/33. ISSN 0067-0049. S2CID 117788987.
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