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]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| 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 mas[1] |
| 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 mas[6] |
| 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 |
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 edit
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f g h Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
- ^ a b Osawa, Kiyoteru (1959). "Spectral Classification of 533 B8-A2 Stars and the Mean Absolute Magnitude of A0 V Stars". Astrophysical Journal. 130: 159. Bibcode:1959ApJ...130..159O. doi:10.1086/146706.
- ^ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b Abt, Helmut A.; Snowden, Michael S. (February 1973). "The Binary Frequency for AP Stars". Astrophysical Journal Supplement. 25: 137. Bibcode:1973ApJS...25..137A. doi:10.1086/190265.
- ^ Hohle, M. M.; et al. (April 2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID 111387483.
- ^ a b c d 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. arXiv:1807.06902. Bibcode:2018MNRAS.480.2953G. doi:10.1093/mnras/sty1912. S2CID 119062018.
- ^ "HD 172044". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-25.
- ^ 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
- ^ "HD 172044B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-25.
External links edit
- alcyone software - star data pages Archived 2007-06-21 at the Wayback Machine