HD 85709

HD 85709
Location of HD 85709 on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 09h 53m 42.92424s[1]
Declination +05° 57′ 30.8742″[1]
Apparent magnitude (V) 5.95[2] (5.89 - 5.95)[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M2.5 III[5]
U−B color index +1.93[6]
B−V color index +1.66[6]
Variable type suspected[7]
Astrometry
Radial velocity (Rv)−0.66±0.40[8] km/s
Proper motion (μ) RA: −3.026 mas/yr[1]
Dec.: +1.315 mas/yr[1]
Parallax (π)2.9474 ± 0.107 mas[1]
Distance1,110 ± 40 ly
(340 ± 10 pc)
Absolute magnitude (MV)−1.30[9]
Details
Radius133±7[10] R☉
Luminosity1,918±144[11] L☉
Surface gravity (log g)0.469[12] cgs
Temperature3,622±125[12] K
Metallicity [Fe/H]+0.23[13] dex
Other designations
14 G. Sextantis[14], NSV 18292, AG+06°1262, BD+06°2224, GC 13608, HD 85709, HIP 48519, HR 3915, SAO 117975
Database references
SIMBADdata

HD 85709 (HR 3915; 14 G. Sextantis; NSV 18292) is a solitary star[15] located in the equatorial constellation Sextans. It is faintly visible to the naked eye as a red-hued point of light with an apparent magnitude of 5.95.[2] The object is located relatively far at a distance of 1,100 light-years based on Gaia DR3 parallax measurements but it is slowly drifting closer with a heliocentric radial velocity of −0.66 km/s.[8] At its current distance, HD 85709's brightness is diminished with an interstellar extinction of two-tenths of a magnitude[16] and it has an absolute magnitude of −1.30.[9]

HD 85709 has a stellar classification of M2.5 III,[5] indicating that it is an evolved M-type giant star. It is currently on the asymptotic giant branch,[4] the point where it is generating energy via the fusion of hydrogen and helium shells around an inert carbon core. Having expanded to 133 times the radius of the Sun,[10] it now radiates 1,918 times the luminosity of the Sun[11] from its enlarged photosphere at an effective temperature of 3,622 K.[12] HD 85709 is metal enriched with an iron abundance 1.58 times that of the Sun's.[13]

In 1991, astronomer V.G. Kornilov and colleagues observed that HD 85709 fluctuated between magnitudes 5.89 and 5.95 in optical light during a photometry survey.[3] As of 2004 however, its variability has not been confirmed.[17]

  1. ^ a b c d Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Ducati2002 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Kornilov1991 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Eggen1992 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Wilson1950 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Famaey2005 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference McDonald2017 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Zhou1991 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Samus2004 was invoked but never defined (see the help page).