LP 944-20

LP 944-20 is a dim brown dwarf of spectral class M9 located about 21 light-years from the Solar System in the constellation of Fornax. With a visual apparent magnitude of 18.69, it has one of the dimmest visual magnitudes listed on the RECONS page.

LP 944-20
Observation data
Epoch J2000      Equinox J2000
Constellation Fornax
Right ascension 03h 39m 35.220s[1]
Declination –35° 25′ 44.09″[1]
Apparent magnitude (V) 18.69
Characteristics
Spectral type M9[1]
Apparent magnitude (B) ~20.17[1]
Apparent magnitude (I) ~13.288[1]
Apparent magnitude (J) 10.725±0.021[1]
Apparent magnitude (H) 10.017±0.021[1]
Apparent magnitude (K) 9.548±0.023[1]
Astrometry
Proper motion (μ) RA: 308.868[1] mas/yr
Dec.: 268.194[1] mas/yr
Parallax (π)155.7590 ± 0.0991[2] mas
Distance20.94 ± 0.01 ly
(6.420 ± 0.004 pc)
Absolute magnitude (MV)20.02
Details[3]
Mass0.06±0.04 M☉
Temperature2650±30 K
Rotation<4.5 h
Rotational velocity (v sin i)28±4 km/s
Age0.32±0.08 years
Other designations
LP 944-20, SIPS J0339−3525, LEHPM 3451, 2MASSI J0339352−352544, [B2006] J033935.2−352544, APMPM J0340−3526, 2MASS J03393521-3525440, 2MASSW J0339352−352544, BRI B0337−3535, BRI 0337−3535, 2MUCD 10201, Gaia DR2 4860376345833699840
Database references
SIMBADdata

Physical characteristics

Due to short rotational period, his young brown dwarf is displaying strong and frequent X-ray flares, and possessing a strong magnetic field reaching 135 G at the photosphere level.[3]On 15 December 1999 an X-ray flare was detected.[4][5] On 27 July 2000, radio emission (in flare and quiescence) was detected from this brown dwarf by a team of students at the Very Large Array.[6]

Observations published in 2007 showed that the atmosphere of LP 944-20 contains much lithium and that it has dusty clouds.[7]


Notes

    References
    1. "SIPS J0339-3525 -- Brown Dwarf (M<0.08solMass)". Centre de Données astronomiques de Strasbourg. Retrieved 2009-12-14.
    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. Guenther, E. W.; Zapatero Osorio, M. R.; Mehner, A.; Martín, E. L. (2009), "Short-term spectroscopic monitoring of two cool dwarfs with strong magnetic fields", Astronomy & Astrophysics, 498: 281–287, arXiv:0903.2340, doi:10.1051/0004-6361/200810216, S2CID 18611224
    4. Rutledge, Robert E.; Basri, Gibor; Martín, Eduardo L.; Bildsten, Lars (1 August 2000). "Chandra Detection of an X-Ray Flare from the Brown Dwarf LP 944-20". The Astrophysical Journal. 538 (2): L141–L144. arXiv:astro-ph/0005559. Bibcode:2000ApJ...538L.141R. doi:10.1086/312817. S2CID 17800872.
    5. "LP 944-20". Solstation.com. Retrieved 2017-03-11.
    6. Berger, E.; Ball, S.; Becker, K. M.; Clarke, M.; Frail, D. A.; Fukuda, T. A.; Hoffman, I. M.; Mellon, R.; Momjian, E.; Murphy, N. W.; Teng, S. H.; Woodruff, T.; Zauderer, B. A.; Zavala, R. T. (2001-03-15). "Discovery of radio emission from the brown dwarf LP944-20". Nature. 410 (6826): 338–340. arXiv:astro-ph/0102301. Bibcode:2001Natur.410..338B. doi:10.1038/35066514. PMID 11268202. S2CID 4411256.
    7. Pavlenko, Ya. V.; Jones, H. R. A.; Martín, E. L.; Guenther, E.; Kenworthy, M. A.; Zapatero Osorio, M. R. (September 2007). "Lithium in LP944-20". Monthly Notices of the Royal Astronomical Society. 380 (3): 1285–96. arXiv:0707.0694. Bibcode:2007MNRAS.380.1285P. doi:10.1111/j.1365-2966.2007.12182.x. S2CID 11186385.
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