HD 98617
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  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Chamaeleon[1] |
| Right ascension | 11h 18m 34.40370s[2] |
| Declination | −79° 40′ 07.1370″[2] |
| Apparent magnitude (V) | 6.35±0.01[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | A8 IIIm:[4] |
| U−B color index | +0.08[5] |
| B−V color index | +0.26[5] |
| Astrometry | |
| Radial velocity (Rv) | −4±2.1[6] km/s |
| Proper motion (μ) | RA: +46.293 mas/yr[2] Dec.: −37.910 mas/yr[2] |
| Parallax (π) | 15.7985±0.069 mas[2] |
| Distance | 206.4 ± 0.9 ly (63.3 ± 0.3 pc) |
| Absolute magnitude (MV) | +2.42[1] |
| Details | |
| Mass | 1.75±0.07[7] M☉ |
| Radius | 1.85±0.06[8] R☉ |
| Luminosity | 8.41[9] L☉ |
| Surface gravity (log g) | 4.20±0.04[7] cgs |
| Temperature | 7,540±276[10] K |
| Metallicity [Fe/H] | −0.03[11] dex |
| Age | 1.06[11] Gyr |
| Other designations | |
| 30 G. Chamaeleontis[12], CD−78°457, CPD−78°638, FK5 2904, GC 15572, HD 98617, HIP 55225, HR 4385, SAO 256823, WDS J11186-7940AB[13] | |
| Database references | |
| SIMBAD | data |
HD 98617, also known HR 4385, is a double star located in the southern circumpolar constellation Chamaeleon. The system has a combined apparent magnitude of 6.35,[3] placing it near the limit for naked eye. The system is located relatively close at a distance of 206 light years[2] but is approaching the Solar System with a fairly constrained radial velocity of −4 km/s.[6] At its current distance, HD 98617 brightness is diminished by 0.29 magnitudes due to interstellar dust.[14]
The system's nature as a double star was first observed in a 1991 Hipparcos multiplicity survey. Their current separation is six-tenths of an arcsecond, making it difficult to measure the properties of the individual components. Nevertheless, the 10th magnitude companion is located along a position angle of 237° as of 2018.[15]
The primary has a stellar classification of A8 IIIm:, indicating that it is an evolved Am star (with uncertainty).[4] However, Renson and Manfroid (2009) lists its chemical peculiarity to be doubtful.[16] It has 1.75 times the mass of the Sun[7] and 1.85 times its girth.[8] It radiates 8.41 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 7,540 K,[10] giving it a white hue. It is estimated to be a billion years old and has a solar metallicity.[11] The aforementioned parameters belong to an A-type main-sequence star instead of a giant star and Gaia DR3 even models it as such.[2]
