LP 944-20

Coordinates: 03h 39m 35.22s, −35° 25′ 44.09″

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[3][4] mas
Distance20.9 ± 0.1 ly
(6.41 ± 0.04 pc)
Absolute magnitude (MV)20.02
Details
Mass0.07[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
SIMBADdata

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 an X-ray flare was detected.[5][6] 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, reported in the 15 March 2001 issue of the journal Nature.[7]

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 [8]) of mas, which corresponds to a distance of 5±0.1 pc, or 16.2±0.3 ly.[9] (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.[10]

Notes

  1. ↑ In RECONS' TOP100 older versions the standard deviation value was 4.20 mas, not 4.21 mas.

References

  1. 1 2 3 4 5 6 7 8 9 10 "SIPS J0339-3525 -- Brown Dwarf (M<0.08solMass)". Centre de Données astronomiques de Strasbourg. Retrieved 2009-12-14.
  2. 1 2 3 4 Research Consortium on Nearby Stars (1 January 2012). "The 100 nearest star systems". RECONS. Georgia State University. Retrieved 12 February 2017.
  3. 1 2 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.
  4. ↑ 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.
  5. ↑ 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.
  6. ↑ "LP 944-20". Solstation.com. Retrieved 2017-03-11.
  7. ↑ 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.
  8. ↑ Mean and Variance of Random Variables
  9. ↑ 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.
  10. ↑ 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.
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