HD 1690
Star in the constellation of Cetus From Wikipedia, the free encyclopedia
HD 1690 is a giant star with an orbiting exoplanet companion in the constellation of Cetus. It has an apparent visual magnitude of 9.19,[2] which is too faint to be visible to the naked eye. The distance to this system is approximately 2,570 light years, and it is drifting further away with a radial velocity of +18.2 km/s.[4] HD 1690 has no known companion star, making it a single star system.[9]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 21m 13.327s[1] |
| Declination | −08° 16′ 52.16″[1] |
| Apparent magnitude (V) | 9.19[2] |
| Characteristics | |
| Evolutionary stage | Giant |
| Spectral type | K1 III[3] |
| B−V color index | 1.354±0.045[2] |
| Astrometry | |
| Radial velocity (Rv) | +18.216±0.011[4] km/s |
| Proper motion (μ) | RA: 13.285 mas/yr[1] Dec.: 2.919 mas/yr[1] |
| Parallax (π) | 1.2679 ± 0.0273 mas[1] |
| Distance | 2,570 ± 60 ly (790 ± 20 pc) |
| Details | |
| Mass | 1.18±0.23[5] M☉ |
| Radius | 16.7[6] R☉ |
| Surface gravity (log g) | 2.12±0.17[5] cgs |
| Temperature | 4,393±85 K |
| Metallicity [Fe/H] | −0.32±0.06 dex |
| Rotational velocity (v sin i) | 1.86±0.07 km/s |
| Age | 6.7±3.2[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is an evolved K-type giant star with a stellar classification of K1 III.[3] It has 1.18 times the mass of the Sun and, at the estimated age of 6.7 billion years (two billion years older than the Sun), it has expanded to 16 times the Sun's radius. The surface metallicity of HD 1690 (the abundance of elements more massive than helium) is 30% that of the sun.[5] The Hipparcos parallax data have resulted in a distance determination of just 1,012 light years,[10] but more recent data from Gaia data have placed HD 1690 much farther from the Sun at 2,500 light years.[11]
Planetary system
In 2010, a team of astronomers led by astronomer C. Moutou of the High Accuracy Radial Velocity Planet Searcher performed a radial-velocity analysis that detected a gas giant planet in orbit around HD 1690.[7]
The planet HD 1690 b has a very eccentric (far from circular) orbit; its orbital eccentricity is 0.64. This eccentricity suggests that its mass is at least six times that of Jupiter, classifying it as a super-Jupiter.[7] Other planets in the HD 1690 system are unlikely unless they are located on unstable crossing orbital paths.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >6.9±0.9 MJ | 1.3±0.02 | 533±1.7 | 0.64±0.04 | — | — |
References
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