| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 04m 12.1045s[2] |
| Declination | +26° 25′ 07.819″[2] |
| Apparent magnitude (V) | +14.61[3] |
| Characteristics | |
| Evolutionary stage | subdwarf B |
| Spectral type | sdB[4] |
| Variable type | V361 Hydrae (sdBVr)[5] |
| Astrometry | |
| Proper motion (μ) | RA: −4.906(40) mas/yr[2] Dec.: −3.703(34) mas/yr[2] |
| Parallax (π) | 0.7388 ± 0.0327 mas[2] |
| Distance | 4,400 ± 200 ly (1,350 ± 60 pc) |
| Absolute magnitude (MV) | +3.88[4] |
| Details | |
| Mass | 0.47[4] M☉ |
| Radius | 0.23[4] R☉ |
| Luminosity | 34[4] L☉ |
| Surface gravity (log g) | 5.4±0.1[6] cgs |
| Temperature | 29,300±500[6] K |
| Age | >10[7] Gyr |
| Other designations | |
HS 2201+2610, 2MASS J22041211+2625078 | |
| Database references | |
| SIMBAD | data |
V391 Pegasi, also catalogued as HS 2201+2610, is a blue-white subdwarf star approximately 4,400 light-years away in the constellation of Pegasus. The star is classified as an "extreme horizontal branch star". It is small, with only half the mass and a bit less than one quarter the diameter of the Sun. It has luminosity 34 times that of the Sun. It could be quite old, perhaps in excess of 10 Gyr. It is a pulsating variable star of the V361 Hydrae type (or also called sdBVr type). It is believed that the star's mass when it was still on the main sequence was between 0.8 and 0.9 times that of the Sun.[7]
- ^ Cite error: The named reference
SilvottiPhotwas invoked but never defined (see the help page). - ^ a b c d Cite error: The named reference
Gaia DR3was invoked but never defined (see the help page). - ^ Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". VizieR On-line Data Catalog. Bibcode:2012yCat.1322....0Z.
- ^ a b c d e Silvotti, R.; Schuh, S.; Kim, S.L.; Lutz, R.; Reed, M.; Benatti, S.; Janulis, R.; Lanteri, L.; Østensen, R.; Marsh, T.R.; Dhillon, V.S. (March 2018), "The sdB pulsating star V391 Peg and its putative giant planet revisited after 13 years of time-series photometric data.", Astronomy & Astrophysics, 611: A85, arXiv:1711.10942, Bibcode:2018A&A...611A..85S, doi:10.1051/0004-6361/201731473, S2CID 119492634
- ^ Samus, N. N.; Durlevich, O. V.; 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
- ^ a b R. Østensen; J.-E. Solheim; U. Heber; R. Silvotti; et al. (2001), "Detection of pulsations in three subdwarf B stars", Astronomy and Astrophysics, 368 (1): 175–182, Bibcode:2001A&A...368..175O, doi:10.1051/0004-6361:20000488
- ^ a b Silvotti, R.; Schuh, S.; Janulis, R.; Solheim, J. -E.; Bernabei, S.; Østensen, R.; Oswalt, T. D.; Bruni, I.; Gualandi, R.; Bonanno, A.; Vauclair, G.; Reed, M.; Chen, C. -W.; Leibowitz, E.; Paparo, M.; Baran, A.; Charpinet, S.; Dolez, N.; Kawaler, S.; Kurtz, D.; Moskalik, P.; Riddle, R.; Zola, S. (2007), "A giant planet orbiting the 'extreme horizontal branch' star V391 Pegasi" (PDF), Nature, 449 (7159): 189–91, Bibcode:2007Natur.449..189S, doi:10.1038/nature06143, PMID 17851517, S2CID 4342338