HD 171819

HD 171819
Location of HD 171819 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Telescopium
Right ascension 18h 39m 14.29289s[1]
Declination −47° 54′ 35.1520″[1]
Apparent magnitude (V) 5.84±0.01[2]
Characteristics
Spectral type A7 IV/V[3] or A3 V[4]
B−V color index +0.23[5]
Astrometry
Radial velocity (Rv)−9±4.3[6] km/s
Proper motion (μ) RA: +25.426 mas/yr[1]
Dec.: +13.951 mas/yr[1]
Parallax (π)10.4348 ± 0.1045 mas[1]
Distance313 ± 3 ly
(95.8 ± 1.0 pc)
Absolute magnitude (MV)+0.65[7]
Details
Mass1.73+0.37
−0.19[8] M☉
Radius3.37±0.17[9] R☉
Luminosity33.3±0.1[1] L☉
Surface gravity (log g)3.60±0.08[8] cgs
Temperature7,512[10] K
Metallicity [Fe/H]−0.02[11] dex
Age855[1] Myr
Other designations
22 G. Telescopii[12], CD−48°12644, CPD−48°9900, FK5 3482, GC 25474, HD 171819, HIP 91461, HR 6986, SAO 229165[13]
Database references
SIMBADdata

HD 171819, also known as HR 6986 or rarely 22 G. Telescopii, is a solitary star[14] located in the southern constellation Telescopium. It is faintly visible to the naked eye as a white-hued object with an apparent magnitude of 5.84.[2] The object is located relatively close at a distance of 313 light years based on Gaia DR3 parallax measurements, but it is approaching the Solar System with a heliocentric radial velocity of −9 km/s.[6] At its current distance, HD 171819's brightness is diminished by one-quarter of a magnitude due to interstellar dust[15] and it has an absolute magnitude of +0.65.[7]

HD 171819 has a stellar classification of A7 IV/V, indicating that the object is a late A-type star with the blended luminosity class of a main sequence star and subgiant.[3] However, astronomer William Buscombe gave it a class of A3 V,[4] instead making it an ordinary A-type main-sequence star. Evolutionary models give it an age of 855 million years and place it towards the end of its main-sequence life.[1] At present it has 1.73 times the mass of the Sun[8] and a slightly enlarged radius 3.37 times that of the Sun.[9] It radiates 33.3 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 7,512 K.[10] HD 171819 has a near solar metallicity at [Fe/H] = −0.02.[11]

  1. ^ a b c d e f g h 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 Houk1978 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Buscombe1969 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Stoy1968 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. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Stassun2018 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Gontcharov2012A 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 Eggleton2008 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).