79 Ceti
Binary star system in the constellation of Cetus
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79 Ceti, also known as HD 16141, is a binary star system located 123 light-years from the Sun in the southern constellation of Cetus. It has an apparent visual magnitude of +6.83, which puts it below the normal limit for visibility with the average naked eye. The star is drifting closer to the Earth with a heliocentric radial velocity of −51 km/s.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus[1] |
| A | |
| Right ascension | 02h 35m 19.9292s[2] |
| Declination | −03° 33′ 38.173″[2] |
| Apparent magnitude (V) | +6.83[1] |
| B | |
| Right ascension | 02h 35m 19.8725s[3] |
| Declination | −03° 33′ 44.340″[3] |
| Apparent magnitude (V) | +14.4[4] |
| Characteristics | |
| A | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G2V[5][6] |
| B−V color index | 0.670±0.004[1] |
| B | |
| Evolutionary stage | main sequence[7] |
| Spectral type | M2.5[7] |
| Astrometry | |
| Radial velocity (Rv) | −50.93±0.09[1] km/s |
| Absolute magnitude (MV) | +3.88[1] |
| A | |
| Proper motion (μ) | RA: −155.501[2] mas/yr Dec.: −437.848[2] mas/yr |
| Parallax (π) | 26.5057±0.0271 mas[2] |
| Distance | 123.1 ± 0.1 ly (37.73 ± 0.04 pc) |
| B | |
| Proper motion (μ) | RA: −141.533[3] mas/yr Dec.: −442.657[3] mas/yr |
| Parallax (π) | 26.5223±0.0353 mas[3] |
| Distance | 123.0 ± 0.2 ly (37.70 ± 0.05 pc) |
| Details | |
| 79 Ceti A | |
| Mass | 1.01[8] M☉ |
| Radius | 1.48[9] R☉ |
| Luminosity | 1.99±0.04[8] L☉ |
| Surface gravity (log g) | 4.19±0.02[8] cgs |
| Temperature | 5,806±17[8] K |
| Metallicity [Fe/H] | +0.16±0.01[8] dex |
| Rotational velocity (v sin i) | 1.9[7] km/s |
| Age | 6.0[10] or 9.4±0.8[1] Gyr |
| 79 Ceti B | |
| Mass | 0.286[6] M☉ |
| Radius | 0.361+0.004 −0.001[3] R☉ |
| Luminosity | 0.0132+0.009 −0.004[3] L☉ |
| Surface gravity (log g) | 4.84+0.02 −0.09[3] cgs |
| Temperature | 3,265+3 −17[3] K |
| Other designations | |
| 79 Cet, BD−04°426, FK5 4237, GJ 9085, HD 16141, HIP 12048, SAO 129992, WDS J02353-0334A, 2MASS J02351994-0333376, Gaia DR2 2495335115182966016[11] | |
| Database references | |
| SIMBAD | data |
| B | |
Harlan (1974) assigned this star a stellar classification of G2V,[5] matching an ordinary G-type main-sequence star that is undergoing core hydrogen fusion. However, Houk and Swift (1999) found a class of G8IV,[12] which suggests it has exhausted the supply of hydrogen at its core and begun to evolve off the main sequence. Eventually the outer layers of the star will expand and cool and the star will become a red giant. Estimates of the star's age range from 6.0[10] to 9.4 billion years old.[1] It has an estimated 1.06 times the mass of the Sun and 1.48 times the Sun's radius.[9] The star is radiating twice[8] luminosity of the Sun from its photosphere at an effective temperature of 5,806 K.[8]
A red dwarf companion at a projected separation of 220 AU was discovered in 2005.[13] There is a suspicion that the companion may itself be a close binary.[4]
Planetary system
On March 29, 2000, a planet orbiting primary star was announced, it was discovered using the radial velocity method.[14] This object has a minimum 0.26 times the mass of Jupiter and is orbiting its host star every 75.5 days.[15]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥0.260±0.028 MJ | 0.363±0.021 | 75.523±0.055 | 0.252±0.052 | — | — |