HD 98617

HD 98617
Location of HD 98617 on the map (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Chamaeleon
Right ascension 11h 18m 34.40370s[1]
Declination −79° 40′ 07.1370″[1]
Apparent magnitude (V) 6.35±0.01[2]
Characteristics
Evolutionary stage main sequence[1]
Spectral type A8 IIIm:[3]
U−B color index +0.08[4]
B−V color index +0.26[4]
Astrometry
Radial velocity (Rv)−4±2.1[5] km/s
Proper motion (μ) RA: +46.293 mas/yr[1]
Dec.: −37.910 mas/yr[1]
Parallax (π)15.7985 ± 0.069 mas[1]
Distance206.4 ± 0.9 ly
(63.3 ± 0.3 pc)
Absolute magnitude (MV)+2.42[6]
Details
Mass1.75±0.07[7] M☉
Radius1.85±0.06[8] R☉
Luminosity8.41[9] L☉
Surface gravity (log g)4.20±0.04[7] cgs
Temperature7,540±276[10] K
Metallicity [Fe/H]−0.03[11] dex
Age1.06[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
SIMBADdata

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,[2] placing it near the limit for naked eye. The system is located relatively close at a distance of 206 light years[1] but is approaching the Solar System with a fairly constrained radial velocity of −4 km/s.[5] 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).[3] 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.[1]

  1. ^ a b c d e f g 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 Houk1975 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference AP1999 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Chanlder2016 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 Gontcharov2012 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gontcharov2017 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 Renson2009 was invoked but never defined (see the help page).