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.
| 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: 309.001±0.050[2] mas/yr  Dec.: 269.058±0.064[2] mas/yr  | 
| Parallax (π) | 155.5982 ± 0.0522 mas[2] | 
| Distance | 20.961 ± 0.007 ly  (6.427 ± 0.002 pc)  | 
| Absolute magnitude (MV) | 20.02 | 
| Details[3] | |
| Mass | 0.06±0.04 M☉ | 
| Temperature | 2650±30 K | 
| Rotation | <4.5 h | 
| Rotational velocity (v sin i) | 28±4 km/s | 
| Age | 0.32±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 | |
| SIMBAD | data | 
![]() LP 944-20 Location of LP 944-20 in the constellation Fornax  | |
Physical characteristics
    
Due to short rotational period, this 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
    
- "SIPS J0339-3525 -- Brown Dwarf (M<0.08solMass)". Centre de Données astronomiques de Strasbourg. Retrieved 2009-12-14.
 - Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
 - Guenther, E. W.; Zapatero-Osorio, María Rosa; Mehner, A.; Martín, Eduardo L. (2009), "Short-term spectroscopic monitoring of two cool dwarfs with strong magnetic fields", Astronomy & Astrophysics, 498 (1): 281–287, arXiv:0903.2340, Bibcode:2009A&A...498..281G, doi:10.1051/0004-6361/200810216, S2CID 18611224
 - 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.
 - "LP 944-20". Solstation.com. Retrieved 2017-03-11.
 - 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.
 - Pavlenko, Ya. V.; Jones, H. R. A.; Martín, Eduardo L.; Guenther, E.; Kenworthy, M. A.; Zapatero-Osorio, María Rosa (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.
 
