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[2] |
| 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: 317±60[1] mas/yr Dec.: 276±52[1] mas/yr |
| Parallax (π) | 155.89 ± 1.03 mas[3][4] |
| Distance | 20.9 ± 0.1 ly (6.41 ± 0.04 pc) |
| Absolute magnitude (MV) | 20.02 |
| Details | |
| Mass | 0.07[2] M☉ |
| 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 | |
| Database references | |
| SIMBAD | data |
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,[2] it has one of the dimmest visual magnitudes listed on the RECONS page.
On 15 December 1999 a flare was detected.[5]
Distance
The first parallax measurement from 1996 found that LP 944-20 (designated there as BRI 0337−3535) has a relative parallax of mas, and its correction from relative to absolute parallax (i.e. mean parallax of the reference frame stars) is mas. This yields an absolute parallax of mas, with a standard deviation (according to [6]) of mas, which corresponds to a distance of 5±0.1 pc, or 16.2±0.3 ly.[7] (The same values of absolute parallax and its standard deviation are in the RECONS' TOP100 list.[2][note 1]
A newer parallax, published in 2013, is 155.89±1.03 mas (6.41±0.04 pc or 20.92±0.14 ly).[3]
Lithium and clouds
Observations published in 2007 showed that the atmosphere of LP 944-20 contains much lithium and that it has dusty clouds.[8]
Notes
- ^ In RECONS' TOP100 older versions the standard deviation value was 4.20 mas, not 4.21 mas.
References
- ^ a b c d e f g h i j "SIPS J0339-3525 -- Brown Dwarf (M<0.08solMass)". Centre de Données astronomiques de Strasbourg. Retrieved 2009-12-14.
- ^ a b c d Research Consortium on Nearby Stars, Georgia State University (January 1, 2012). "The 100 nearest star systems". RECONS. Retrieved 2012-06-11.
{{cite journal}}: Check|first=value (help); External link in|journal= - ^ a b
Dieterich, Sergio B.; Todd J. Henry; Wei-Chun Jao; Jennifer G. Winters; Altonio D. Hosey (2013). "The Solar Neighborhood XXXII: The Hydrogen Burning Limit". arXiv:1312.1736v1.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Lurie, John C.; Henry, Todd J.; Jao, Wei-Chun; Quinn, Samuel N.; Winters, Jennifer G.; Ianna, Philip A.; Koerner, David W.; Riedel, Adric R.; Subasavage, John P. (2014). "The Solar Neighborhood. XXXIV. a Search for Planets Orbiting Nearby M Dwarfs Using Astrometry". The Astronomical Journal. 148 (5): 91. arXiv:1407.4820. Bibcode:2014AJ....148...91L. doi:10.1088/0004-6256/148/5/91.
- ^ http://www.solstation.com/stars/lp944-20.jpg
- ^ Mean and Variance of Random Variables
- ^
Tinney, C. G. (1996). "CCD astrometry of southern very low-mass stars". Monthly Notices of the Royal Astronomical Society. 281 (2): 644–658. Bibcode:1996MNRAS.281..644T. doi:10.1093/mnras/281.2.644.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Pavlenko, Ya. V.; et al. (September 2007). "Lithium in LP944-20". Monthly Notices of the Royal Astronomical Society. 380 (3): 1285–1296. arXiv:0707.0694. Bibcode:2007MNRAS.380.1285P. doi:10.1111/j.1365-2966.2007.12182.x.
{{cite journal}}: CS1 maint: unflagged free DOI (link)
