HD 65216
Triple star-system in the constellation Carina
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HD 65216 is a triple[6] star system with two exoplanetary companions in the southern constellation of Carina. With an apparent visual magnitude of 7.97[1] it cannot be readily seen without technical aid, but with binoculars or telescope it should be visible. The system is located at a distance of 114.7 light-years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 42.6 km/s.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Carina[1] |
| A | |
| Right ascension | 07h 53m 41.3196s[2] |
| Declination | −63° 38′ 50.353″[2] |
| Apparent magnitude (V) | 7.97[1] |
| B | |
| Right ascension | 07h 53m 42.3964s[3] |
| Declination | −63° 38′ 50.182″[3] |
| Apparent magnitude (V) | 18.58[4] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | G5V[5] + M7–8 + L2–3[6] |
| B−V color index | 0.672±0.012[1] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | 42.58±0.12[2] km/s |
| Proper motion (μ) | RA: −123.740±0.029 mas/yr[2] Dec.: +146.602±0.023 mas/yr[2] |
| Parallax (π) | 28.4419±0.0181 mas[2] |
| Distance | 114.67 ± 0.07 ly (35.16 ± 0.02 pc) |
| Absolute magnitude (MV) | 5.22[1] |
| B | |
| Proper motion (μ) | RA: −119.227 mas/yr[3] Dec.: +134.271 mas/yr[3] |
| Parallax (π) | 27.7827±0.1542 mas[3] |
| Distance | 117.4 ± 0.7 ly (36.0 ± 0.2 pc) |
| Details | |
| HD 65216 A | |
| Mass | 0.95±0.01[7] M☉ |
| Radius | 0.864±0.003[7] R☉ |
| Luminosity | 0.716±0.001[7] L☉ |
| Surface gravity (log g) | 4.53±0.01[7] cgs |
| Temperature | 5,718±8[7] K |
| Metallicity [Fe/H] | −0.17[8] dex |
| Rotational velocity (v sin i) | 1.308[8] km/s |
| Age | 1.7±0.5[7] Gyr |
| Ba | |
| Mass | 0.09[4] M☉ |
| Bb | |
| Mass | 0.08[4] M☉ |
| Other designations | |
| CD−63°359, HD 65216, HIP 38558, SAO 250002, WDS J07537-6339A[9] | |
| Database references | |
| SIMBAD | data |
Stellar system
The primary of HD 65216, component A, is an ordinary G-type main-sequence star with a stellar classification of G5V.[5] It is nearly two billion years old[7] and is spinning with a projected rotational velocity of 1.3 km/s.[8] The star has 95% of the mass and 86% of the radius of the Sun. It is radiating 72% of the luminosity of the Sun from its photosphere at an effective temperature of 5,718 K.[7]
In 2008 a co-moving binary system of low mass companions were discovered at an angular separation of 7″ from the primary, which is equivalent to a projected separation of 253 AU at the distance of HD 65216. Component B is of class M7–8 (0.089 M☉) while component C is class L2–3 (0.078 M☉); both have a mass close to the sub-stellar limit. The pair have a projected separation of 6 AU from each other.[6]
Planetary system
An extrasolar planet (designated as HD 65216 b) was discovered orbiting the primary in 2003.[10] A second much more distant planet was suspected since 2013,[11] but was discovered on a completely different orbit in 2019.[12]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.295±0.062 MJ | 1.301±0.020 | 577.6±1.328 | 0.27±0.02 | — | — |
| c | ≥2.03±0.11 MJ | 5.75±0.09 | 5370±20 | 0.17±0.04 | — | — |