  | |
| Observation data Epoch J2000.0[1] Equinox J2000.0[1] | |
|---|---|
| Constellation | Volans |
| Right ascension | 08h 55m 16.81719s |
| Declination | −67° 15′ 55.7009″ |
| Apparent magnitude (V) | 7.82[2] |
| Characteristics | |
| Evolutionary stage | Red-giant branch star[3] |
| Spectral type | K1 III[3] |
| B−Vcolor index | 1.11[2] |
| J−Hcolor index | 0.537[4] |
| J−Kcolor index | 0.693[4] |
| Astrometry | |
| Radial velocity (Rv) | 20.09 ± 0.14[5] km/s |
| Proper motion (μ) | RA: 25.253[6]mas/yr Dec.: 25.659[6]mas/yr |
| Parallax (π) | 5.4618±0.0187 mas[6] |
| Distance | 597 ± 2 ly (183.1 ± 0.6 pc) |
| Details[3] | |
| Mass | 1.22±0.11 M☉ |
| Radius | 8.68±0.34 R☉ |
| Luminosity | 29.5+1.3 −1.0[7] L☉ |
| Surface gravity (log g) | 2.648±0.037 cgs |
| Temperature | 4664±53 K |
| Metallicity [Fe/H] | −0.19±0.06 dex |
| Rotational velocity (v sin i) | 2.5±0.3[7] km/s |
| Age | 5.2±1.4 Gyr |
| Other designations | |
| CD−66°659,CPD−66°943,Gaia DR2 5224124307320401024,HD 76920,HIP 43803,SAO 250379,PPM 357010,TIC 302372658,TYC 8939-1192-1,GSC 08939-01192,2MASS J08551682-6715555[1] | |
| Database references | |
| SIMBAD | data |
HD 76920 is a solitary[8] orange-hued star with an orbitingexoplanetary companion in thesouthernconstellation ofVolans, close to the border withCarina. With anapparent magnitude of 7.82, it is too faint to be seen by thenaked eye fromEarth but is readily observable throughbinoculars.[9] It is located at a distance of 597 light-years (183 parsecs) according toGaia EDR3parallax measurements, and is moving away at a heliocentricradial velocity of 20.09 km/s.
This is an aginggiant star with astellar classification of K1 III. At the age of5.2±1.4 billion years, it hasevolved past themain sequence after depleting itshydrogen supply at thecore. It is currently in the midst ofascending the red-giant branch (RGB), fast approaching the RGB bump, where deepstellar convection temporarily stalls the ascent. As expected of RGB stars, it exhibitssolar-like oscillations. It has 1.22 times themass of the Sun but has expanded to 8.68 times theSun's radius.[3] The star is radiating 29.5 times theluminosity of the Sun from its inflatedphotosphere at aneffective temperature of 4,664 K (4,391 °C; 7,936 °F).[7]
In 2017,radial-velocity observations made usingspectrographs at theAnglo-Australian Telescope, theCerro Tololo Inter-American Observatory, and theMPG/ESO telescope revealed the existence of an exoplanet around HD 76920.[8] The planet, HD 76920 b, is aneccentric Jupiter with aminimum mass of 3.57MJ[3] and a very highorbital eccentricity of 0.8782,[7] which at the time of discovery made it the most eccentric known planet orbiting an evolved star. Since the host star appears to be single, this was likely caused by ascattering event rather thanKozai oscillations.[8]
Because of its high eccentricity, despite an Earth-likesemi-major axis of 1.165 AU and a period of 415.891 days (1.13865 years), the planet approaches the star to within 2.4 stellar radii at itsperihelion.[7] This is currently not causing any substantialorbital decay; thus the planet is expected to survive for the next 50–80 million years without falling into the star.[7] However, after about 100 million years, stellar evolution andtidal interactions will doom it to be engulfed.[3]
The planet has a relatively high probability (16%) totransit its host star, but such a transit has yet to be detected byTESS.[7]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 3.57 ± 0.22 MJ | 1.165 ± 0.035 | 415.891+0.043 −0.039[7] | 0.8782 ± 0.0025[7] | — | 1.17[10] RJ |
