| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 23 29 09.29698 |
| Declination | +12° 45′ 37.9918″ |
| Apparent magnitude (V) | 4.56 |
| Characteristics | |
| Spectral type | G8 IIIa |
| B−V color index | 0.940 |
| Astrometry | |
| Radial velocity (Rv) | −16.88±0.43 km/s |
| Proper motion (μ) | RA: +61.40 mas/yr Dec.: +24.82 mas/yr |
| Parallax (π) | 18.65 ± 0.78 mas |
| Distance | 175 ± 7 ly (54 ± 2 pc) |
| Absolute magnitude (MV) | 0.90 |
| Orbit | |
| Period (P) | 941.03±0.12 d |
| Eccentricity (e) | 0.713±0.006 |
| Argument of periastron (ω) (secondary) | 57.0±1.2° |
| Semi-amplitude (K1) (primary) | 3.16±0.04 km/s |
| Details | |
| 70 Peg A | |
| Mass | 2.49±0.06 M☉ |
| Radius | 8.95±0.69 R☉ |
| Luminosity | 49.2±2.4 L☉ |
| Surface gravity (log g) | 2.92±0.05 cgs |
| Temperature | 5,108±185 K |
| Metallicity | 0.05±0.03 dex |
| Rotational velocity (v sin i) | 3.6 km/s |
| Age | 590±40 Myr |
| Other designations | |
| 70 Peg, BD+11° 5009, FK5 885, HD 221115, HIP 115919, HR 8923, SAO 108638 | |
| Database references | |
| SIMBAD | data |
70 Pegasi is a binary star system in the northern constellation Pegasus. It is a faint star, visible to the naked eye under good seeing conditions, with an apparent visual magnitude of 4.56. The measured annual parallax shift measured from Earth's orbit is 18.65 mas, yielding a distance estimate of around 175 light years. The visual magnitude of the star is diminished by an extinction of 0.07±0.02 due to interstellar dust. It is moving closer to the Sun with a radial velocity of −17 km/s.
This is a single-lined spectroscopic binary with an orbital period of 2.58 years (941 days) and a high eccentricity of 0.713. The visible component has a stellar classification of G8 IIIa, indicating it is an evolved G-type giant star. It is a probable red clump star, which would mean it is generating energy through helium fusion at its core. The star has 2.5 times the mass of the Sun and has expanded to nine times the Sun's radius. It is radiating about 49 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,108 K.
The secondary is most likely a low mass main sequence star with no more than 0.4 times the mass of the Sun.
References
- ^ van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
- ^ Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ^ Maldonado, J.; et al. (June 2013), "The metallicity signature of evolved stars with planets", Astronomy & Astrophysics, 554: 18, arXiv:1303.3418, Bibcode:2013A&A...554A..84M, doi:10.1051/0004-6361/201321082, S2CID 119289111, A84
- 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.
- ^ Griffin, R. F. (August 2009), "Spectroscopic binary orbits from photoelectric radial velocities. Paper 207: 58 Piscium, 31 Vulpeculae, and 70 Pegasi", The Observatory, 129: 198−218, Bibcode:2009Obs...129..198G.
- ^ Baines, Ellyn K.; Clark, James H., III; Schmitt, Henrique R.; Stone, Jordan M.; von Braun, Kaspar (2023-12-01). "33 New Stellar Angular Diameters from the NPOI, and Nearly 180 NPOI Diameters as an Ensemble". The Astronomical Journal. 166 (6): 268. Bibcode:2023AJ....166..268B. doi:10.3847/1538-3881/ad08be. ISSN 0004-6256.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
- "70 Peg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-20.
- Puzeras, E.; et al. (October 2010), "High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements", Monthly Notices of the Royal Astronomical Society, 408 (2): 1225−1232, arXiv:1006.3857, Bibcode:2010MNRAS.408.1225P, doi:10.1111/j.1365-2966.2010.17195.x, S2CID 44228180
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