Astronomy:HD 179791
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 13m 44.03146s[1] |
| Declination | +05° 30′ 56.1725″[1] |
| Apparent magnitude (V) | 6.48[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A3 V[4] |
| U−B color index | +0.10[2] |
| B−V color index | +0.09[2] |
| Variable type | suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | +16.2[6] km/s |
| Proper motion (μ) | RA: +6.819[1] mas/yr Dec.: −9.809[1] mas/yr |
| Parallax (π) | 5.2966 ± 0.0569[1] mas |
| Distance | 616 ± 7 ly (189 ± 2 pc) |
| Absolute magnitude (MV) | 0.66[7] |
| Details | |
| Mass | 2.55±0.15[3] M☉ |
| Radius | 2.5[8] R☉ |
| Luminosity | 65.8+21.0 −16.0[3] L☉ |
| Temperature | 8912+166 −162[3] K |
| Rotational velocity (v sin i) | 196[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 179791 is suspected variable star[5] in the equatorial constellation of Aquila. It is a challenge to see with the naked eye even under good viewing conditions, having an apparent visual magnitude of 6.48.[2] The distance to HD 179791 can be estimated from its annual parallax shift of 5.3 mas,[1] which yields a value of 616 light years. It is moving further from the Earth with a heliocentric radial velocity of +16 km/s.[6] Astrometric measurements of the star show changes in motion that may indicate it is a member of a close binary system.[10]
This is an A-type main-sequence star with a stellar classification of A3 V.[4] It is a suspected chemically peculiar star and formerly a candidate Lambda Boötis star.[11] The status as a Lambda Boötis star was reviewed and changed to non-member in 2015.[12] It is spinning rapidly with a projected rotational velocity of 196 km/s.[3] The star has 2.55[3] times the mass of the Sun and about 2.5[8] times the Sun's radius. It is radiating 66[3] times the Sun's luminosity from its photosphere at an effective temperature of 8,912 K.[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.
- ↑ 2.0 2.1 2.2 2.3 Cousins, A. W. J. (1965), "Photometric Data for Stars in the Equatorial Zone (Eighth List)", Monthly Notes of the Astronomical Society of Southern Africa 24: 120, Bibcode: 1965MNSSA..24..120C.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C.
- ↑ 5.0 5.1 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 6.0 6.1 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 8.0 8.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ "HD 179791". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+179791.
- ↑ Mason, Brian D.; Martin, Christian; Hartkopf, William I.; Barry, Donald J.; Germain, Marvin E.; Douglass, Geoffrey G.; Worley, Charles E.; Wycoff, Gary L. et al. (1999), "Speckle Interferometry of New and Problem HIPPARCOS Binaries", The Astronomical Journal 117 (4): 1890, doi:10.1086/300823, Bibcode: 1999AJ....117.1890M
- ↑ Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics 498 (3): 961–966, doi:10.1051/0004-6361/200810788, Bibcode: 2009A&A...498..961R.
- ↑ Cheng, Kwang-Ping et al. (January 2017), "Utilizing Synthetic Visible Spectra to Explore the Physical Basis for the Classification of Lambda Boötis Stars", The Astronomical Journal 153 (1): 15, doi:10.3847/1538-3881/153/1/39, 39, Bibcode: 2017AJ....153...39C.
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