HD 154577 (Gliese 656) is a solar-type star in the southern constellation of Ara. It is a high proper motion star and, based upon an annual parallax shift of 73.41 mas,[1] is located about 44 light years from the Sun. The star is too faint to be readily visible to the naked eye, having an apparent visual magnitude of 7.4.[2] It is moving away from the Sun with a radial velocity of +9 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 10m 10.35091s[1] |
| Declination | −60° 43′ 43.5757″[1] |
| Apparent magnitude (V) | 7.385[2] |
| Characteristics | |
| Spectral type | K2.5Vk:[3] |
| U−B color index | +0.53[4] |
| B−V color index | +0.89[4] |
| Astrometry | |
| Radial velocity (Rv) | +8.8[5] km/s |
| Proper motion (μ) | RA: 70.96[1] mas/yr Dec.: 589.86[1] mas/yr |
| Parallax (π) | 73.41 ± 0.70 mas[1] |
| Distance | 44.4 ± 0.4 ly (13.6 ± 0.1 pc) |
| Absolute magnitude (MV) | 6.71[2] |
| Details | |
| Mass | 0.68[6] M☉ |
| Radius | 0.68[7] R☉ |
| Luminosity | 0.24[8] L☉ |
| Surface gravity (log g) | 4.70[3] cgs |
| Temperature | 4,850[3] K |
| Metallicity [Fe/H] | −0.70[9] dex |
| Rotational velocity (v sin i) | 0.2[10] km/s |
| Age | 3.2[11] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
This star has only 68% of the Sun's mass and radius, an effective temperature of 4,850 K and a stellar classification of K2.5Vk:,[3] which indicates it is a K-type main sequence star. (The 'k' suffix indicates there are interstellar absorption features in the spectra, while ':' means there is some uncertainty about the classification.) It is about 3.2[11] billion years old and appears to be spinning slowly with a projected rotational velocity of 0.2 km/s.[10] The star is radiating 24%[8] of the Sun's luminosity from its photosphere at an effective temperature of 4,850 K.[3]
As of 2005, this star is not known to host any planets.[6] No excess of infrared radiation has been detected of the type that would indicate the presence of an orbiting debris disk.[11]
References
edit- ^ a b c d e f 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.
- ^ a b c Holmberg, J.; Nordström, B.; Andersen, J. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics Supplement Series. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. S2CID 118577511. Note: see VizieR catalogue V/130.
- ^ a b c d e Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
- ^ a b Cousins, A. W. J. (1973). "UBV photometry of some southern stars". Monthly Notes of the Astronomical Society of Southern Africa. 32: 11. Bibcode:1973MNSSA..32...11C.
- ^ a b Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.
- ^ a b Santos, N. C.; et al. (July 2005). "Spectroscopic metallicities for planet-host stars: Extending the samples". Astronomy and Astrophysics. 437 (3): 1127–1133. arXiv:astro-ph/0504154. Bibcode:2005A&A...437.1127S. doi:10.1051/0004-6361:20052895. S2CID 16256304.
- ^ Takeda, Genya; et al. (February 2007), "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog", The Astrophysical Journal Supplement Series, 168 (2): 297–318, arXiv:astro-ph/0607235, Bibcode:2007ApJS..168..297T, doi:10.1086/509763, S2CID 18775378.
- ^ a b 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.
- ^ Adibekyan, V. Zh.; et al. (September 2012), "Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program. Galactic stellar populations and planets", Astronomy & Astrophysics, 545: 15, arXiv:1207.2388, Bibcode:2012A&A...545A..32A, doi:10.1051/0004-6361/201219401, S2CID 118300756, A32.
- ^ a b Valenti, Jeff A.; Fischer, Debra A. (July 2005), "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs", The Astrophysical Journal Supplement Series, 159 (1): 141–166, Bibcode:2005ApJS..159..141V, doi:10.1086/430500.
- ^ a b c Lawler, S. M.; et al. (November 2009). "Explorations Beyond the Snow Line: Spitzer/IRS Spectra of Debris Disks Around Solar-type Stars". The Astrophysical Journal. 705 (1): 89–111. arXiv:0909.0058. Bibcode:2009ApJ...705...89L. doi:10.1088/0004-637X/705/1/89. S2CID 1272803.
- ^ "LHS 3268 -- High proper-motion star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-12-06.