![]() HD 87643 is embedded in the faint nebulosity at the centre of this image. The red arc is NGC 3199, a Wolf–Rayet nebula around WR 18. | |
Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Carina |
Right ascension | 10h 04m 30.2840s [1] |
Declination | −58° 39′ 52.091″ [1] |
Apparent magnitude (V) | 8.87 [2] (7.4 - 9.8 [3] ) |
Characteristics | |
Spectral type | B3 I[e] [4] |
U−B color index | −0.54 [2] |
B−V color index | +0.69 [2] |
Variable type | INA [3] |
Astrometry | |
Proper motion (μ) | RA: −7.557 [1] mas/yr Dec.: +5.438 [1] mas/yr |
Parallax (π) | 0.6293±0.1227 mas [1] |
Distance | approx. 5,000 ly (approx. 1,600 pc) |
Absolute magnitude (MV) | −4.1 [5] |
Details | |
Mass | 25 [6] M☉ |
Luminosity | 41,000 [7] L☉ |
Temperature | 17,000 [7] K |
Other designations | |
V640 Carinae, CD −58°3005, HD 87643, SAO 237672, RAFGL 4767, 2MASS J10043028-5839521, AAVSO 1001-58 | |
Database references | |
SIMBAD | data |
HD 87643 is a B[e] class binary star embedded in a reflection nebula.
The system is described as having "one of the most extreme infrared excesses for this object class". It harbours a large amount of both hot and cold dust, and is surrounded by a debris disk with radius 2.5-3 AU [6] and an extended reflection nebula. and is important for astronomers in their study of stellar formation. [8]
All the properties of HD 87643 are highly uncertain. Its distance has been estimated anywhere from one to six kpc. In 1996, Carol Anne Grady et al. announced that the star is a variable star. [9] It was given its variable star designation, V640 Carinae, in 2008. [10] The General Catalogue of Variable Stars classifies it as an Orion variable, a pre-main sequence star, but other authors consider it to be a supergiant B[e] star. It has been confirmed to be a binary star system with the two stars separated by about 52 AU, but the nature of the companion is unknown. [8]