Gamma1 Caeli
Double star in the constellation Caelum
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Gamma1 Caeli is a double star in the southern constellation of Caelum. Its name is a Bayer designation that is Latinized from γ1 Caeli, and abbreviated Gamma1 Cae or γ1 Cae. This pair consists of an orange hued giant and a fainter yellow subgiant star with an angular separation of 3.20″, as of 2016.[11] The brighter component is faintly visible to the naked eye with an apparent visual magnitude of 4.57.[2] Based on parallax measurements, it is located at a distance of approximately 185 light-years (57 pc) from the Earth. This star is drifting further away from the Sun with a radial velocity of +10 km/s.[7]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Caelum |
| γ1 Caeli A | |
| Right ascension | 05h 04m 24.402s[1] |
| Declination | −35° 28′ 58.71″[1] |
| Apparent magnitude (V) | 4.57±0.01[2] |
| γ1 Caeli B | |
| Right ascension | 05h 04m 24.191s[3] |
| Declination | −35° 28′ 56.86″[3] |
| Apparent magnitude (V) | 8.07±0.01[2] |
| Characteristics | |
| γ1 Caeli A | |
| Spectral type | K2III-IIIb[4] |
| U−B color index | 1.197[5] |
| B−V color index | 1.198[5] |
| γ1 Caeli B | |
| Spectral type | G8IV[6] |
| B−V color index | 0.84[2] |
| Astrometry | |
| γ1 Caeli A | |
| Radial velocity (Rv) | 9.96±0.19[7] km/s |
| Proper motion (μ) | RA: 125.972 mas/yr[7] Dec.: −42.909 mas/yr[7] |
| Parallax (π) | 17.5912±0.0834 mas[1] |
| Distance | 185.4 ± 0.9 ly (56.8 ± 0.3 pc) |
| γ1 Caeli B | |
| Proper motion (μ) | RA: 123.107 mas/yr[3] Dec.: −45.167 mas/yr[3] |
| Parallax (π) | 17.5332±0.024 mas[3] |
| Distance | 186.0 ± 0.3 ly (57.03 ± 0.08 pc) |
| Details | |
| γ1 Caeli A | |
| Mass | 1.4+1.1 −0.4[8] M☉ |
| Radius | 14.31+0.27 −0.56[7] R☉ |
| Luminosity | 69.9±0.8[7] L☉ |
| Temperature | 4,411+89 −41[7] K |
| Metallicity [Fe/H] | −0.1[8] dex |
| Rotational velocity (v sin i) | <1[9] km/s |
| γ1 Caeli B | |
| Mass | 0.91[10] M☉ |
| Surface gravity (log g) | 4.45[10] cgs |
| Temperature | 5,702[10] K |
| Metallicity [Fe/H] | −0.1[10] dex |
| Other designations | |
| γ1 Cae, CD−35 2089, HD 32831, HIP 23595, HR 1652, SAO 195532, WDS J05044-3529 | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
Properties
Gamma1 Caeli A is an evolved K-type giant star with a stellar classification of K2III-IIIb.[4] It is 40% more massive than the Sun and has expanded to 14.3 times the Sun's girth. This star is radiates 69.9 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,411 K. It is metal poor, with 79% the abundance of elements more massive than helium compared to the Sun.
Gamma1 Caeli B has an apparent magnitude of 8.07, which makes it visible only in binoculars or a telescope, and is located at a similar distance to Component A with a comparable proper motion. It has a class of G8IV,[6] matching an aging G-type subgiant star that has exhausted the supply of hydrogen at its core and is evolving away from the main sequence. This star has 91% of the Sun's mass.