2MASS J0523−1403

2MASS J0523−1403 is a very-low-mass red dwarf about 40 light-years from Earth in the southern constellation of Lepus. With a very faint visual magnitude of 21.05 and a low effective temperature of 2074 K it is visible primarily in large telescopes sensitive to infrared light. 2MASS J0523−1403 was first observed as part of the Two Micron All-Sky Survey (2MASS).[7]

2MASS J0523−1403
Observation data
Epoch J2000      Equinox J2000
Constellation Lepus
Right ascension  05h 23m 38.221s[1]
Declination −14° 03′ 02.29″[1]
Apparent magnitude (V) 21.05[2]
Characteristics
Spectral type L2.5V[2]
Astrometry
Radial velocity (Rv)12.21 ± 0.09[3] km/s
Proper motion (μ) RA: 107.254±0.290[4] mas/yr
Dec.: 160.897±0.341[4] mas/yr
Parallax (π)78.3632 ± 0.1855[4] mas
Distance41.62 ± 0.10 ly
(12.76 ± 0.03 pc)
Absolute magnitude (MV)20.6[2]
Details
Mass67.54±12.79[5] MJup
Radius1.01±0.07[5] RJup
Luminosity0.000138[5] L☉
Surface gravity (log g)5.21±0.16[5] cgs
Temperature1939±68[5] K
Rotational velocity (v sin i)21[6] km/s
Other designations
2MASS J05233822−1403022, 2MUCD 10390, B2006 J052338.2−140302, 2MASSI J0523382−140302, USNO-B1.0 0759−00062850
Database references
SIMBADdata

Characteristics

2MASS J0523−1403 has a luminosity of 0.000126 L☉, a radius of 0.086 R☉, and an effective temperature of 2074 K. These values are currently the lowest known for a main-sequence star.[2] It has a stellar classification of L2.5 and a V−K color index of 9.42.[2] The mass is calculated to be 67.54±12.79 MJ (0.0644±0.0122 M☉).[5] Observation with the Hubble Space Telescope has detected no companion beyond 0.15 arcsecond.[8] Sporadic radio emissions were detected by the VLA in 2004.[9] H-alpha (Hα) emissions have also been detected, a sign of chromospheric activity.[6]

Hydrogen burning limit

Members of the RECONS group have recently identified 2MASS J0523−1403 as representative of the smallest possible stars.[10] Its small radius is at the local minimums of the radius–luminosity and radius–temperature trends.[2] This local minimum is predicted to occur at the hydrogen burning limit due to differences in the radius-mass relationships of stars and brown dwarfs. Unlike stars, brown dwarfs decrease in radius as mass increases due to their cores being supported by degeneracy pressure. As the mass increases an increasing fraction of the brown dwarf is degenerate causing the radius to shrink as mass increases.[10] The minimum stellar mass is estimated to be between 0.07 and 0.077 M☉, comparable to the mass of 2MASS J0523−1403.[2]

See also

References
  1. "2MASS J05233822-1403022". SIMBAD - Centre de données astronomiques de Strasbourg. Retrieved 14 December 2013.
  2. Dieterich, Sergio B.; Henry, Todd J.; Jao, Wei-Chun; Winters, Jennifer G.; Hosey, Altonio D.; Riedel, Adric R.; Subasavage, John P. (May 2014). "The Solar Neighborhood XXXII. The Hydrogen Burning Limit". The Astronomical Journal. 147 (5). article id 94. arXiv:1312.1736. Bibcode:2014AJ....147...94D. doi:10.1088/0004-6256/147/5/94.
  3. Blake, Cullen H.; Charbonneau, David; White, Russel J. (2010). "The NIRSPEC Ultracool Dwarf Radial Velocity Survey". The Astrophysical Journal. 723 (1): 684–706. arXiv:1008.3874. Bibcode:2010ApJ...723..684B. doi:10.1088/0004-637X/723/1/684.
  4. 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.
  5. Filippazzo, Joseph C.; Rice, Emily L.; Faherty, Jacqueline; Cruz, Kelle L.; Van Gordon, Mollie M.; Looper, Dagny L. (2015). "Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime". The Astrophysical Journal. 810 (2): 158. arXiv:1508.01767. Bibcode:2015ApJ...810..158F. doi:10.1088/0004-637X/810/2/158.
  6. Reiners, A.; Basri, G. (2008). "Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs". The Astrophysical Journal. 684 (2): 1390–1403. arXiv:0805.1059v2. Bibcode:2008ApJ...684.1390R. doi:10.1086/590073.
  7. Cruz, Kelle L.; Reid, I. Neill; Liebert, James; Kirkpatrick, J. Davy; Lowrance, Patrick J. (2003). "Meeting the Cool Neighbors. V. A 2MASS-Selected Sample of Ultracool Dwarfs". The Astronomical Journal. 126 (5): 2421–2448. arXiv:astro-ph/0307429. Bibcode:2003AJ....126.2421C. doi:10.1086/378607.
  8. Reid, I. Neill; Lewitus, E.; Allen, P. R.; Cruz, Kelle L.; Burgasser, Adam J. (2006). "A Search for Binary Systems among the Nearest L Dwarfs". The Astronomical Journal. 132 (2): 891–901. arXiv:astro-ph/0606331. Bibcode:2006AJ....132..891R. doi:10.1086/505626.
  9. Antonova, A.; Doyle, J. G.; Hallinan, G.; Golden, A.; Koen, C. (2 September 2007). "Sporadic long-term variability in radio activity from a brown dwarf". Astronomy and Astrophysics. 472 (1): 257–260. arXiv:0707.0634. Bibcode:2007A&A...472..257A. doi:10.1051/0004-6361:20077231.
  10. Garmany, Katy (9 December 2013). "NOAO/SOAR: Where do stars end and brown dwarfs begin?" (Press release). National Optical Astronomy Observatory. Retrieved 14 December 2013.
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