Astronomy:1 Pegasi
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 21h 22m 05.19950s [1] |
| Declination | 19° 48′ 16.2375″ [1] |
| Apparent magnitude (V) | 4.09[2] |
| Characteristics | |
| Spectral type | K1III[3] |
| U−B color index | +1.05[2] |
| B−V color index | +1.11[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.80[4] km/s |
| Proper motion (μ) | RA: +105.391[1] mas/yr Dec.: +62.841[1] mas/yr |
| Parallax (π) | 20.8482 ± 0.1452[1] mas |
| Distance | 156 ± 1 ly (48.0 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.68[5] |
| Details[6] | |
| 1 Peg A | |
| Mass | 1.60±0.18 M☉ |
| Radius | 11.89±0.15 R☉ |
| Luminosity | 63.5±0.3 L☉ |
| Surface gravity (log g) | 2.59[7] cgs |
| Temperature | 4,725±64 K |
| Metallicity [Fe/H] | +0.01[7] dex |
| Rotational velocity (v sin i) | 1.2[8] km/s |
| Age | 2.04±0.54 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
1 Pegasi (1 Peg) is a triple star[10] system in the constellation Pegasus, located approximately 156 light years away from the Sun based on parallax.[1] It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.09.[2] The system is moving closer to the Earth with a heliocentric radial velocity of −11 km/s.[4]
The primary component is a giant with a stellar classification of K1III,[3] a star that has exhausted the hydrogen supply at its core and evolved away from the main sequence. Estimated to be two billion years old, 1 Pegasi has 1.6 times the mass of the Sun and has expanded to twelve times the Sun's radius. The star is radiating 64 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,725 K.[6]
There are several companions in addition to the primary. The brightest, component B, is a magnitude 9.3, K-type main-sequence star with a class of K0 V orbiting at an angular separation of 36.6" from the primary; it is itself a single-lined spectroscopic binary with an orbital period of 3.042 ± 0.011 years and eccentricity of 0.290±0.022.[11] Visual companions C, with magnitude 12.9 and separation 64.7", and D, with magnitude 9.6 and separation 5.3", have been reported.[12]
1 Pegasi is the brightest star in Pegasus that does not have a Bayer designation, although it is brighter than several stars in Pegasus that do such as τ, φ, and σ Pegasi, perhaps because it was included as the brightest star in the constellation Battery of Volta, made by Thomas Young. It is the first star numbered by Flamsteed in order of right ascension. In the 1795 French-language Fortin-Flamsteed edition of the Atlas Coelestis, 1 Pegasi is labelled with the letter "e".[13]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode: 2002yCat.2237....0D.
- ↑ 3.0 3.1 Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H 5050. Bibcode: 1995yCat.5050....0H.
- ↑ 4.0 4.1 Bakos, G. A. (1974). "Radial velocity measurements of visual binaries. 1". The Astronomical Journal 79: 866. doi:10.1086/111622. Bibcode: 1974AJ.....79..866B.
- ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. Vizier catalog entry
- ↑ 6.0 6.1 Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; Van Belle, Gerard T. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal 155 (1): 30, doi:10.3847/1538-3881/aa9d8b, Bibcode: 2018AJ....155...30B.
- ↑ 7.0 7.1 Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics 525: A71. doi:10.1051/0004-6361/201015014. Bibcode: 2011A&A...525A..71W.
- ↑ De Medeiros, J. R.; Mayor, M. (1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series 139 (3): 433. doi:10.1051/aas:1999401. Bibcode: 1999A&AS..139..433D. Vizier catalog entry
- ↑ "1 Peg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=1+Peg.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. Vizier catalog entry
- ↑ Griffin, R. F. (February 1987). "Spectroscopic binary orbits from photoelectric radial velocities. Paper 72: 1 Pegasi B". The Observatory 107: 1–5. Bibcode: 1987Obs...107....1G.
- ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M. Vizier catalog entry
- ↑ Flamsteed, John; Fortin, Jean Nicolas; De Lalande, Joseph Jerome Lefrancais (1795). "Atlas celeste". Paris: Delamarche. Bibcode: 1795atce.book.....F.
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