HW Virginis
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
---|---|
Constellation | Virgo |
Right ascension | 12h 44m 20.2367s |
Declination | −08° 40′ 16.837″ |
Apparent magnitude (V) | 10.9 |
Distance | 590 ± 65 ly (181 ± 20 pc) |
Spectral type | sdB / M V |
Other designations | |
HIP 62157
|
|
Database references | |
SIMBAD | data |
HW Virginis, abbreviated HW Vir, is an eclipsing binary system (of the Algol type) approximately 590 light-years away (based on the stellar properties and magnitudes: the Hipparcos trigonometric parallax measurement has too high an error value to be useful[1]) in the constellation of Virgo. The system comprises an eclipsing B-type subdwarf star and red dwarf star. The two stars orbit each other every 0.116795 days.[2]
Eclipse timing variations
Based on variations in the timing of the system's eclipses, in 2008 it was claimed that two giant planets were in orbit around the binary: one with a masses of 8.47 and 19.2 times the mass of Jupiter orbiting with periods of 9.1 and 15.8 years respectively.[1] The proposed system was later shown to be extremely unstable, with mean lifetimes less than 1000 years in the parameter space allowed by the uncertainties in the data.[3] An alternate, dynamically-stable orbital solution was proposed with a 14.3 Jupiter mass object on a 12-year orbit and an outer companion of 65 Jupiter masses on a 55-year orbit,[4] however it has been noted that the outer companion's orbital parameters are highly unconstrained, again casting doubt on the reality of this model.[3] The problems with modelling this system and the proposed planets orbiting several other post-common envelope binaries has led to the suggestion that the eclipse timing variations used to infer the existence of planets has a non-planetary origin.[5]
See also
References
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External links
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Coordinates: 12h 44m 20.2367s, −08° 40′ 16.837″
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