Astronomy:9 Equulei
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Short description: Star in the constellation Equuleus
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 21m 04.825s[1] |
| Declination | +07° 21′ 16.21″[1] |
| Apparent magnitude (V) | 5.798[2] |
| Characteristics | |
| Evolutionary stage | AGB[3] |
| Spectral type | M2IIIa[4] |
| U−B color index | +1.97[5] |
| B−V color index | +1.66[5] |
| Variable type | suspected[6] |
| Astrometry | |
| Radial velocity (Rv) | −21.82±0.30[1] km/s |
| Proper motion (μ) | RA: 43.871±0.274[1] mas/yr Dec.: −17.822±0.261[1] mas/yr |
| Parallax (π) | 4.3895 ± 0.1647[1] mas |
| Distance | 740 ± 30 ly (228 ± 9 pc) |
| Absolute magnitude (MV) | −0.69[7] |
| Details | |
| Mass | 1.2[8] M☉ |
| Radius | 58[1] R☉ |
| Luminosity | 720[1] L☉ |
| Surface gravity (log g) | 1.64[8] cgs |
| Temperature | 3,920[1] K |
| Metallicity [Fe/H] | −0.27[8] dex |
| Other designations | |
HIP 105413, HD 203291, HR 8163, SAO 126719 | |
| Database references | |
| SIMBAD | data |
9 Equulei is an M-type star in the constellation Equuleus. It is an asymptotic giant branch (AGB) star, a star that has exhausted its core helium and is now fusing both hydrogen and helium in shells outside the core.[3] It is also a suspected variable star with an amplitude of about 0.05 magnitudes.[6]
The spectral type is M2IIIa, meaning it is a relatively cool giant star. As an AGB star, it is burning hydrogen and helium in shells around an inert carbon-oxygen core. It has expanded to 58 times the radius of the Sun, and it radiates 720 times as much electromagnetic radiation from a photosphere with an effective temperature of 3,920 K.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 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.
- ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27. Bibcode: 2000A&A...355L..27H.
- ↑ 3.0 3.1 Eggen, Olin J. (1992). "Asymptotic Giant Branch Stars Near the Sun". The Astronomical Journal 104: 275. doi:10.1086/116239. Bibcode: 1992AJ....104..275E.
- ↑ Yamashita, Y. (1967). "MK Spectral Types of Bright M-Type Stars". Publications of the Dominion Astrophysical Observatory Victoria 13: 47. Bibcode: 1967PDAO...13...47Y.
- ↑ 5.0 5.1 Hoffleit, Dorrit; Jaschek, Carlos (1991). "The Bright star catalogue". New Haven, Conn.: Yale University Observatory, 5th Rev.ed.. Bibcode: 1991bsc..book.....H.
- ↑ 6.0 6.1 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1: B/GCVS. Bibcode: 2009yCat....102025S.
- ↑ 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 8.2 Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G. et al. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics 691: A98. doi:10.1051/0004-6361/202451427. Bibcode: 2024A&A...691A..98K.
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