HD 101917
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  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Chamaeleon[1] |
| Right ascension | 11h 42m 54.93206s[2] |
| Declination | −79° 18′ 23.0075″[2] |
| Apparent magnitude (V) | 6.38±0.01[3] |
| Characteristics | |
| Evolutionary stage | red giant branch[2] |
| Spectral type | K0 III/IV[4] |
| U−B color index | +0.59[5] |
| B−V color index | +0.90[5] |
| Astrometry | |
| Radial velocity (Rv) | 32.5±0.4[6] km/s |
| Proper motion (μ) | RA: +127.152 mas/yr[2] Dec.: −11.599 mas/yr[2] |
| Parallax (π) | 17.64±0.0224 mas[2] |
| Distance | 184.9 ± 0.2 ly (56.69 ± 0.07 pc) |
| Absolute magnitude (MV) | +2.69[1] |
| Details | |
| Mass | 1.26[7] M☉ |
| Radius | 4.01±0.20[8] R☉ |
| Luminosity | 9.04±0.03[2] L☉ |
| Surface gravity (log g) | 3.32±0.06[9] cgs |
| Temperature | 5,076±19[9] K |
| Metallicity [Fe/H] | −0.11±0.02[9] dex |
| Rotational velocity (v sin i) | <1.4[10] km/s |
| Age | 3.87+0.41 −0.42[2] Gyr |
| Other designations | |
| 34 G. Chamaeleontis[11], CD−78°476, CPD−78°677, GC 16083, HD 101917, HIP 57137, HR 4509, SAO 256865[12] | |
| Database references | |
| SIMBAD | data |
HD 101917, also designated as HR 4509, or rarely 34 G. Chamaeleontis,[11] is a solitary star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude of 6.38,[3] placing it near the limit for naked eye visibility. The object is located relatively close at a distance of 185 light years based on Gaia DR3 parallax measurements[2] but is receding with a heliocentric radial velocity of 33 km/s.[6] At its current distance, HD 101917's brightness is diminished by 0.28 magnitudes due to interstellar dust.[13] It has an absolute magnitude of +2.69.[1]
HD 101917 has a stellar classification of K0 III/IV,[4] indicating that it is an evolved K-type star with the blended luminosity class of a subgiant and a giant star. Gaia DR3 models it to be 3.9 billion years old,[2] enough time for it to cool and expand to 4.01 times the radius of the Sun.[8] At present it has 126% the mass of the Sun[7] and now radiates 9.04 times the luminosity of the Sun from its enlarged photosphere at an effective temperature 5,076 K,[9] giving it a yellow hue. HD 101917 has an iron abundance 22% below solar levels,[9] making it slightly metal deficient. It spins slowly with a projected rotational velocity lower than 1.4 km/s.[10]
