HD 74156
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Stern HD 74156 |
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| AladinLite | |||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Water snake | ||||||||||
| Right ascension | 08 h 42 m 25.12 s | ||||||||||
| declination | + 04 ° 34 ′ 41.2 ″ | ||||||||||
| Apparent brightness | 7.61 likes | ||||||||||
| Typing | |||||||||||
| Known exoplanets | 2 | ||||||||||
| B − V color index | +0.58 | ||||||||||
| Spectral class | G0 | ||||||||||
| Astrometry | |||||||||||
| Radial velocity | (+3.8 ± 0.2) km / s | ||||||||||
| parallax | (15.52 ± 0.54) mas | ||||||||||
| distance | (210 ± 7) ly (64.4 ± 2.2) pc |
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| Visual absolute brightness M vis | +3.6 mag | ||||||||||
| Proper movement | |||||||||||
| Rec. Share: | (24.83 ± 0.64) mas / a | ||||||||||
| Dec. portion: | (−200.90 ± 0.46) mas / a | ||||||||||
| Physical Properties | |||||||||||
| Dimensions | approx. 1.2 M ☉ | ||||||||||
| radius | approx. 1.6 R ☉ | ||||||||||
| Luminosity |
approx. 3.0 L ☉ |
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| Effective temperature | approx. 6000 K | ||||||||||
| Metallicity [Fe / H] | +0.13 | ||||||||||
| Age | approx. 7 bill. a | ||||||||||
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Other names and catalog entries |
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HD 74156 is a yellow dwarf who is surrounded by at least two companions, HD 74156 b and HD 74156 c . The star has the spectral class G0. Its mass is around 1.2 solar masses . Its companions were discovered in 2001 through measurements of its radial velocity .
Possible existence of other exoplanets
In 2007, Barnes et al. based on model calculations, the existence of another exoplanet, HD 74156 d , was predicted in this system. It was assumed that all stable orbits in a system would be occupied by a planet. Since there is a stable zone between the two companions that were first discovered, this suggested another exoplanet on such an orbit. Eventually, confirmation of this companion was claimed by measurements of the radial velocity of the central star. For the exoplanet, an orbital period of around 340 days and a minimum mass of 0.4 Jupiter's masses were determined, the major semi-axis of the orbit was given as 1.0 astronomical units and the numerical eccentricity as 0.25. However, various scientists soon expressed serious doubts about this discovery and a study published in 2009 by Wittenmyer et al. could not confirm the discovery. Thus the existence of the described exoplanet (but not a planet per se) must be considered highly doubtful at the moment. If the doubts dissipate, this would be the first exoplanet successfully predicted to be discovered.