HD 170642

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

HD 170642, also designated as HR 6942 or rarely 13 G. Coronae Australis, is a single star 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. The object is located relatively close at a distance of 229 light years based on Hipparcos parallax measurements, but it is approaching the Solar System with a somewhat constrained heliocentric radial velocity of −6 km/s. At its current distance, HD 170642's brightness is diminished by 0.28 magnitudes due to interstellar dust. It has an absolute magnitude of +0.93.

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

References

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  2. 1 2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
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  13. 1 2 Díaz, C. G.; González, J. F.; Levato, H.; Grosso, M. (July 2011). "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum". Astronomy & Astrophysics. 531: A143. arXiv:1012.4858. Bibcode:2011A&A...531A.143D. doi:10.1051/0004-6361/201016386. eISSN 1432-0746. ISSN 0004-6361.
  14. ↑ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  15. ↑ "HD 170642". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 25, 2022.
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  18. ↑ Evans, D. S. (1966). "Fundamental data for Southern stars (6th list)". Royal Greenwich Observatory Bulletins. 110: 185. Bibcode:1966RGOB..110..185E.