HD 101782

HD 101782
Location of HD 101782 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension 11h 41m 01.30826s[1]
Declination −83° 05′ 59.7773″[1]
Apparent magnitude (V) 6.33±0.01[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type K0 III[4]
U−B color index +0.88[5]
B−V color index +1.08[5]
Astrometry
Radial velocity (Rv)11.5±0.4[6] km/s
Proper motion (μ) RA: −59.825 mas/yr[1]
Dec.: +9.477 mas/yr[1]
Parallax (π)9.1605 ± 0.0172 mas[1]
Distance356.0 ± 0.7 ly
(109.2 ± 0.2 pc)
Absolute magnitude (MV)+1.11[7]
Details
Mass2±0.5[8] M☉
Radius10.1[9] R☉
Luminosity55.25±0.21[1] L☉
Surface gravity (log g)2.73[1] cgs
Temperature4,663±127[10] K
Metallicity [Fe/H]+0.04[11] dex
Rotational velocity (v sin i)<1.1[12] km/s
Age455[1] 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
SIMBADdata

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,[2] 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.[1] It appears to be receding with a heliocentric radial velocity of 11.5 km/s.[6] 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,[4] indicating that it is an evolved red giant. It is currently on the horizontal branch (HB), fusing helium at its core.[3] 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[1] 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]

  1. ^ a b c d e f g h i Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Laney2011 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Charbonnel2020 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Bai2019 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Eggen1989 was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference De Medeiros2014 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Mason2001 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Herschel1835 was invoked but never defined (see the help page).