HD 170642

HD 170642
Location of HD 170642 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Australis
Right ascension 18h 32m 21.33140s[1]
Declination −39° 42′ 14.4023″[1]
Apparent magnitude (V) 5.16±0.01[2]
Characteristics
Spectral type A3 V[3] or A3 Van[4]
B−V color index +0.08[5]
Astrometry
Radial velocity (Rv)−6±4.2[6] km/s
Proper motion (μ) RA: +32.47 mas/yr[1]
Dec.: −37.47 mas/yr[1]
Parallax (π)14.23 ± 0.23 mas[1]
Distance229 ± 4 ly
(70 ± 1 pc)
Absolute magnitude (MV)+0.93[7]
Details
Mass2.25[8] M☉
Radius2.59±0.13[9] R☉
Luminosity32.6[10] L☉
Surface gravity (log g)3.96[11] cgs
Temperature8,938±161[12] K
Metallicity [Fe/H]+0.24[11] dex
Rotational velocity (v sin i)177±1[13] km/s
Age480[8] Myr
Other designations
13 G. Coronae Australis[14], CD−39°12696, CPD−39°8114, GC 25285, HD 170642, HIP 90887, HR 6942, SAO 210277[15]
Database references
SIMBADdata

HD 170642, also designated as HR 6942 or rarely 13 G. Coronae Australis, is a single star[16] located in the southern constellation Corona Australis. It is faintly visible to the naked eye as a white hued star with an apparent magnitude of 5.16.[2] The object is located relatively close at a distance of 229 light years based on Hipparcos parallax measurements,[1] but it is approaching the Solar System with a somewhat constrained heliocentric radial velocity of −6 km/s.[6] At its current distance, HD 170642's brightness is diminished by 0.28 magnitudes due to interstellar dust.[17] It has an absolute magnitude of +0.93.[7]

This is an ordinary A-type main-sequence star with a stellar classification of A3 V.[3] Other sources include broad/nebulous absorption lines due to rapid rotation.[18][4] It has 2.25 times the mass of the Sun and is estimated to be 480 million years old.[8] HD 170642 has a radius of 2.59 R☉.[9] When combined with an effective temperature of 8,938 K,[12] it radiates 32.6 times the luminosity of the Sun[10] from its photosphere. The star is metal enriched, having an iron abundance 74% greater than the Sun's.[11] Like many hot stars HD 170642 spins rapidly, having a projected rotational velocity of 177 km/s.[13]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 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 Houk1982 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gray1989 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Lake1965 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 David2015 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 McDonald2012 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Erspamer2003 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Díaz2011 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 SIMBAD was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Evans1966 was invoked but never defined (see the help page).