ChaHα8 (also written ChaHa8 when Greek letters are unavailable) is a binary brown dwarf about 640 light-years (200 parsecs) from Earth in the constellation Chamaeleon. The designation indicates that it is in the Chamaeleon I star-forming region and that it displays hydrogen-alpha emission. It was discovered in 2000.[5]

ChaHα8

ChaHα8 with the Spitzer Space Telescope
Observation data
Epoch J2000      Equinox J2000
Constellation Chamaeleon
Right ascension 11h 07m 46.091s[1]
Declination −77° 40′ 08.92″[1]
Apparent magnitude (V) 20.1[2]
Characteristics
Spectral type M5.75–M6.5[3]
Astrometry
Proper motion (μ) RA: -23.455 mas/yr[1]
Dec.: 0.453 mas/yr[1]
Parallax (π)5.0899 ± 0.0792 mas[1]
Distance641 ± 10 ly
(196 ± 3 pc)
Orbit[4]
Period (P)1895±132 d
Semi-major axis (a)1.02±0.061.17±0.07 AU
Eccentricity (e)0.59±0.22
Periastron epoch (T)2453163±214 JD
Argument of periastron (ω)
(secondary)
106±26°
Semi-amplitude (K1)
(primary)
2.433±0.44 km/s
Details
ChaHα8 A
Mass0.07–0.10[3] M
Temperature2910–3024[3] K
Rotational velocity (v sin i)15.5±2.6[3] km/s
Age~3[3] Myr
ChaHα8 B
Mass25±731±8[4] MJup
Other designations
2MASS J11074610-7740089, CHSM 10837, SBC9 3352, Cha Hα 8[2]
Database references
SIMBADdata

It was found in 2007 to have a low-mass substellar companion in orbit around it via radial velocity observations.[3] The companion has a mass of 25–31 Jupiter masses, and the pair orbit each other with a period of 5.2 years and an eccentricity of 0.59.[4]

References

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  1. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b "CHSM 10837". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 November 2016.
  3. ^ a b c d e f Joergens, V.; A. Mueller (2007). "16–20 Jupiter mass RV companion orbiting the brown dwarf candidate ChaHa8". The Astrophysical Journal. 666 (2). arXiv:0707.3744. Bibcode:2007ApJ...666L.113J. doi:10.1086/521825. S2CID 119140521.
  4. ^ a b c Joergens, V.; Müller, A.; Reffert, S. (2010). "Improved radial velocity orbit of the young binary brown dwarf candidate Cha Hα 8". Astronomy and Astrophysics. 521 (A24): A24. arXiv:1006.2383. Bibcode:2010A&A...521A..24J. doi:10.1051/0004-6361/201014853. S2CID 54989533.
  5. ^ Comerón, F.; Neuhäuser, R.; Kaas, A. A. (2000). "Probing the brown dwarf population of the Chamaeleon I star forming region". Astronomy and Astrophysics. 359: 269–288. Bibcode:2000A&A...359..269C.
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