Astronomy:HD 172044
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 36m 37.34437s[1] |
| Declination | 33° 28′ 08.5352″[1] |
| Apparent magnitude (V) | 5.41[2] + 10.7[3] |
| Characteristics | |
| Spectral type | B8IIpHgMn[4] |
| U−B color index | −0.509[2] |
| B−V color index | −0.101±0.003[2] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −32.5±0.8[5] km/s |
| Proper motion (μ) | RA: −7.966[1] mas/yr Dec.: +0.690[1] mas/yr |
| Parallax (π) | 6.0990 ± 0.0893[1] mas |
| Distance | 535 ± 8 ly (164 ± 2 pc) |
| Absolute magnitude (MV) | −0.53[2] |
| B | |
| Proper motion (μ) | RA: −7.403[6] mas/yr Dec.: +0.479[6] mas/yr |
| Parallax (π) | 6.2391 ± 0.0221[6] mas |
| Distance | 523 ± 2 ly (160.3 ± 0.6 pc) |
| Orbit[7] | |
| Period (P) | 1675 d |
| Semi-major axis (a) | ≥71.6×108 km |
| Eccentricity (e) | 0.16 |
| Periastron epoch (T) | 2,420,438.5 JD |
| Argument of periastron (ω) (secondary) | 120° |
| Semi-amplitude (K1) (primary) | 3.2 km/s |
| Details | |
| A | |
| Mass | 3.65±0.50[8] M☉ |
| Luminosity | 262.17[2] L☉ |
| Surface gravity (log g) | 3.90[9] cgs |
| Temperature | 14,500[9] K |
| Metallicity [Fe/H] | −0.25[2] dex |
| Rotational velocity (v sin i) | 34[9] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 172044 is a triple star[11] system in the northern constellation of Lyra. It has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of 5.41.[2] The distance to the primary component is approximately 535 light years based on parallax.[1] It is drifting closer with a radial velocity of −32.5 km/s, and is predicted to come as near as 77.3 light-years to the Sun some 4.5 million years from now.[2]
The dual nature of the primary star, component A, was announced in 1973 by H. A. Abt and M. A. Snowden. It is a single-lined spectroscopic binary with a preliminary orbital period of 4.59 years and an eccentricity (ovalness) of 0.16.[7] The visible component is a B-type bright giant with a stellar classification of B8IIpHgMn,[4] where the suffix notation indicates it is a chemically peculiar mercury-manganese star.[9]
Component B is a magnitude 9.40 companion of an unknown spectral type.[12] It was first reported by F. G. W. Struve in 1830. As of 2016, it has an angular separation of 7.2 arcseconds along a position angle of 204° from the brighter component.[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. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Mason, B. D. et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.
- ↑ 4.0 4.1 Osawa, Kiyoteru (1959). "Spectral Classification of 533 B8-A2 Stars and the Mean Absolute Magnitude of A0 V Stars". Astrophysical Journal 130: 159. doi:10.1086/146706. Bibcode: 1959ApJ...130..159O.
- ↑ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
- ↑ 6.0 6.1 6.2 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. Gaia DR2 record for this source at VizieR.
- ↑ 7.0 7.1 Abt, Helmut A.; Snowden, Michael S. (February 1973). "The Binary Frequency for AP Stars". Astrophysical Journal Supplement 25: 137. doi:10.1086/190265. Bibcode: 1973ApJS...25..137A.
- ↑ Hohle, M. M. et al. (April 2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten 331 (4): 349. doi:10.1002/asna.200911355. Bibcode: 2010AN....331..349H.
- ↑ 9.0 9.1 9.2 9.3 Ghazaryan, S. et al. (2018). "New catalogue of chemically peculiar stars, and statistical analysis". Monthly Notices of the Royal Astronomical Society 480 (3): 2953–2962. doi:10.1093/mnras/sty1912. Bibcode: 2018MNRAS.480.2953G.
- ↑ "HD 172044". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+172044.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E.
- ↑ "HD 172044B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+172044B.
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