HD 101782
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  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Chamaeleon[1] |
| Right ascension | 11h 41m 01.30826s[2] |
| Declination | −83° 05′ 59.7773″[2] |
| Apparent magnitude (V) | 6.33±0.01[3] |
| Characteristics | |
| Evolutionary stage | horizontal branch[4] |
| Spectral type | K0 III[5] |
| U−B color index | +0.88[6] |
| B−V color index | +1.08[6] |
| Astrometry | |
| Radial velocity (Rv) | 11.5±0.4[7] km/s |
| Proper motion (μ) | RA: −59.825 mas/yr[2] Dec.: +9.477 mas/yr[2] |
| Parallax (π) | 9.1605±0.0172 mas[2] |
| Distance | 356.0 ± 0.7 ly (109.2 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.11[1] |
| Details | |
| Mass | 2±0.5[8] M☉ |
| Radius | 10.1[9] R☉ |
| Luminosity | 55.25±0.21[2] L☉ |
| Surface gravity (log g) | 2.73[2] cgs |
| Temperature | 4,663±127[10] K |
| Metallicity [Fe/H] | +0.04[11] dex |
| Rotational velocity (v sin i) | <1.1[12] km/s |
| Age | 455[2] Myr |
| Other designations | |
| 33 G. Chamaeleontis[13], CD−82°224, CPD−82°469, GC 16057, HD 101782, HIP 56996, HR 4507, SAO 258621, WDS J11410-8306A[14] | |
| Database references | |
| SIMBAD | data |
HD 101782, also known as HR 4507, is a yellowish-orange hued star located in the southern circumpolar constellation of Chamaeleon. It has an apparent magnitude of 6.33,[3] placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 356 light years away from the Solar System.[2] It appears to be receding with a heliocentric radial velocity of 11.5 km/s.[7] De Mederios found the radial velocity to be variable, suggesting that it may be a spectroscopic binary.[12] Eggen (1989) lists it as a member of the young disk population.[11]
HD 101782 has a stellar classification of K0 III,[5] indicating that it is an evolved red giant. It is currently on the horizontal branch (HB), fusing helium at its core.[4] The star is located on the cool end of the red clump, a region on the HR diagram with metal-rich HB stars. It has double the mass of the Sun[8] but has expanded to 10.1 times its girth.[9] It radiates 55 times the luminosity of the Sun[2] from its photosphere at an effective temperature of 4,663 K.[10] It has an iron abundance 110% that of the Sun's, placing it at solar metallicity.[11] Like most giants it spins slowly, having a projected rotational velocity lower than 1.1 km/s.[12]
TYC 9507-3649-1 is a 10th magnitude optical companion located 25.9″ away along a position angle of 139°.[15] This companion was first noticed by Sir John Herschel in 1837.[16]
