HD 201772

HD 201772
HD 201772 is the star circled in red
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 21h 13m 03.06827s[1]
Declination −39° 25′ 29.7097″[1]
Apparent magnitude (V) 5.26[2]
Characteristics
Spectral type F5 IV-V[3] or F6 V Fe−0.9 CH−0.5[4]
B−V color index +0.44[2]
Astrometry
Radial velocity (Rv)−41±1[5] km/s
Proper motion (μ) RA: +185.855 mas/yr[1]
Dec.: −113.449 mas/yr[1]
Parallax (π)29.2823 ± 0.0827 mas[1]
Distance111.4 ± 0.3 ly
(34.15 ± 0.10 pc)
Absolute magnitude (MV)+2.66[6]
Details
Mass1.5[1] M☉
Radius2.18±0.09[7] R☉
Luminosity7.83±0.04[1] L☉
Surface gravity (log g)3.91±0.09[8] cgs
Temperature6,519±80[9] K
Metallicity [Fe/H]−0.18±0.03[10] dex
Rotational velocity (v sin i)10[11] km/s
Age2.23±0.04 Gyr
Other designations
56 G. Microscopii[12], CD−39°14152, CPD−39°8898, GC 29640, HD 201772, HIP 104738, HR 8104, SAO 212793, LTT 8413[13]
Database references
SIMBADdata

HD 201772, also known as HR 8104, is a yellowish-white hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.26,[2] making it one of the brighter members of this generally faint constellation. The object is located relatively close at a distance of 111 light-years based on Gaia DR3 parallax measurements[1] but is approaching closer with a heliocentric radial velocity of −41 km/s.[5] At its current distance, HD 201772's brightness is diminished by 0.11 magnitudes due to interstellar dust.[14]

The star has been given multiple stellar classifications over the years. It was given the luminosity class of a subgiant and main sequence star (IV/V; IV-V)[15][3] and a dwarf (V).[16][17] Most sources generally agree that it is a F5 star. Richard O. Gray and colleagues give HD 201772 a class of F6 V Fe−0.9 CH−0.5, which indicates that it is a F-type main-sequence star with an underabundance of iron and CH molecules in its spectrum.[4]

It has 1.47 times the mass of the Sun[18] and an enlarged radius of 2.2 R☉.[7] It radiates 7.8 times the luminosity of the Sun from its photosphere at an effective temperature of 6,519 K.[9] At an age of 2.5 billion years, HD 201722 is currently 1.33 magnitudes above the ZAMS, consistent with a star that is evolving off the main sequence.[11] The star has an iron abundance 66% that of the Sun,[10] making it metal deficient. It spins modestly with a projected rotational velocity of 10 km/s.[11]

HD 201772 is suspected to be a spectroscopic binary consisting of the subgiant described above and an ordinary F6 V star with a mass of 1.31 M☉.[19] However, the stars have no separation or an orbital period.[20] This is because the companion might be a result of spectrum contamination, so HD 201772 is more likely to be a solitary star.[21]

  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 c Cite error: The named reference Corben1968 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Gray1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gray2006 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 Cite error: The named reference Masana2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Casagrande2011 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Netopil2017 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Nordstrom2004 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 Adams1935 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Malaroda1975 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Houk1982 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Feltzing2001 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Tokovinin20141 was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference Tokovinin20142 was invoked but never defined (see the help page).
  21. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).