HD 175640 is a star in the equatorial constellation of Aquila. It has an apparent visual magnitude of 6.20,[2] which is bright enough to be visible to the naked eye under suitable seeing conditions. The star is located at a distance of approximately 516 light years as determined through parallax measurements.[1] At that distance, the star's color is modified by an extinction of 0.36 magnitude due to interstellar dust.[8] It is drifting closer with a heliocentric radial velocity of roughly −26 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 18h 56m 22.660s[1] |
| Declination | −01° 47′ 59.50″[1] |
| Apparent magnitude (V) | 6.20[2] |
| Characteristics | |
| Spectral type | B9 IIIp(HgMnEu st, CaMg wk)[3] B9 V[4] |
| B−V color index | −0.046±0.005[2] |
| Variable type | Stable[4] |
| Astrometry | |
| Radial velocity (Rv) | −26±4[2] km/s |
| Proper motion (μ) | RA: −2.811 mas/yr Dec.: −19.318 mas/yr |
| Parallax (π) | 6.3201 ± 0.0448 mas[1] |
| Distance | 516 ± 4 ly (158 ± 1 pc) |
| Absolute magnitude (MV) | 0.22[2] |
| Details | |
| Mass | 3.12±0.1[4] M☉ |
| Radius | 2.66±0.28[4] R☉ |
| Luminosity | 94.56[2] L☉ |
| Surface gravity (log g) | 4.03[5] cgs |
| Temperature | 12324±9[5] K |
| Metallicity [Fe/H] | 0.18±0.04[2] dex |
| Rotational velocity (v sin i) | 1.6±0.3[6] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is classified as a mercury-manganese star, which is a late B-type chemically peculiar star of type CP3. A distinctive feature of this class of stars is an apparent extreme overabundance of the elements mercury and manganese.[9] It has a low longitudinal magnetic field strength of −0.6±2.2 G.[6] This is a particularly stable star, showing no signs of pulsation.[4] As with other HgMn stars, it is spinning slowly, showing a projected rotational velocity of 1.6 km/s.[6]
In 2007, some evidence was found that this may be a single-lined spectroscopic binary star system. In particular, shifts in radial velocity were observed in the range of 7 to −7 km/s.[10]
References
edit- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 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.
- ^ Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", The Astrophysical Journal Supplement Series, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
- ^ a b c d e Ghazaryan, S.; et al. (November 2013), "Attempt to detect the granulation signature in the HgMn star HD 175640 from CoRoT light curves", Monthly Notices of the Royal Astronomical Society, 435 (3): 1852–1856, Bibcode:2013MNRAS.435.1852G, doi:10.1093/mnras/stt1339.
- ^ a b García Pérez, A. E.; et al. (August 2021), "An extension of the MILES library with derived Teff, log g, [Fe/H], and [α/Fe]", Monthly Notices of the Royal Astronomical Society, 505 (3): 4496–4514, Bibcode:2021MNRAS.505.4496G, doi:10.1093/mnras/stab076.
- ^ a b c Kochukhov, O.; et al. (June 2013), "Are there tangled magnetic fields on HgMn stars?", Astronomy & Astrophysics, 554, id. A61, arXiv:1304.6717, Bibcode:2013A&A...554A..61K, doi:10.1051/0004-6361/201321467.
- ^ "HD 175640". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2024-11-12.
- ^ Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
- ^ Castelli, F.; Hubrig, S. (October 2004), "A spectroscopic atlas of the HgMn star HD 175640 (B9 V) λλ 3040-10 000 Å", Astronomy and Astrophysics, 425: 263–270, Bibcode:2004A&A...425..263C, doi:10.1051/0004-6361:20041011.
- ^ Thiam, M.; et al. (2007), Romanyuk, I. I.; Kudryavtsev, D. O. (eds.), "Abundances and chemical stratification in the atmosphere of the HgMn star HD 175640", Physics of Magnetic Stars. Proceedings of the International Conference, held in the Special Astrophysical Observatory of the Russian AS, August 28-31, 2006, pp. 363–368, arXiv:astro-ph/0612323, Bibcode:2007pms..conf..363T.
Further reading
edit- Monier, Richard (October 2024), "Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. VIII. HD 175640", Research Notes of the AAS, 8 (10), id. 254, Bibcode:2024RNAAS...8..254M, doi:10.3847/2515-5172/ad843a.
- Castelli, F.; et al. (August 2015), "New Mn II energy levels from the STIS-HST spectrum of the HgMn star HD 175640", Astronomy & Astrophysics, 580, id. A10, arXiv:1504.07514, Bibcode:2015A&A...580A..10C, doi:10.1051/0004-6361/201525903.