HD 170657
HD 170657 is a star in the constellation Sagittarius. It is located at a distance of about 43 light years. It has 0.79 solar masses and is a suspected variable star that varies in apparent magnitude from 6.82−6.88.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 31m 18.9597s[1] |
| Declination | –18° 54′ 31.722″[1] |
| Apparent magnitude (V) | 6.82 |
| Characteristics | |
| Spectral type | K2V[2] |
| U−B color index | +0.56[3] |
| B−V color index | +0.87[3] |
| Variable type | Suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | –35[5] km/s |
| Proper motion (μ) | RA: –140.14[1] mas/yr Dec.: –194.60[1] mas/yr |
| Parallax (π) | 75.71 ± 0.89[1] mas |
| Distance | 43.1 ± 0.5 ly (13.2 ± 0.2 pc) |
| Details | |
| Mass | 0.79 ± 0.11[6] M☉ |
| Surface gravity (log g) | 4.61[6] cgs |
| Temperature | 5,156[6][7] K |
| Rotational velocity (v sin i) | 1.5[6] km/s |
| Age | 1.6–6.1[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
When observed with the Spitzer Space Telescope, this star did not display an excess emission of infrared radiation, which may otherwise indicate the presence of an orbiting debris disk.[7] The space velocity components of this star are (U, V, W) = (–41, –26, +6) km/s.[9]
Sources give contradictory measurements for the abundance of elements in this star. Lawler et al. (2009) lists an iron abundance of [Fe/H] = 0.27 dex,[7] while Valenti et al. (2005) has an iron abundance of [Fe/H] = –0.15.[6]
References
- Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
- 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.
- Corben, P. M.; Carter, B. S.; Banfield, R. M.; Harvey, G. M. (1972). "UBV Photometry of 500 Southern Stars [erratum: 1973MNSSA..32...48C]". Monthly Notes of the Astronomical Society of Southern Africa. 31: 7. Bibcode:1972MNSSA..31....7C.
- Kukarkin, B. V.; et al. (1981). Nachrichtenblatt der Vereinigung der Sternfreunde e.V. (Catalogue of suspected variable stars). Moscow: Academy of Sciences USSR Shternberg. Bibcode:1981NVS...C......0K.
- 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.
- 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.
- 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.
- "HD 170657 -- Variable Star". Centre de Données astronomiques de Strasbourg. Retrieved 2010-07-21.
- Gliese, W. (1969). Catalogue of Nearby Stars. Heidelberg: Veröffentlichungen des Astronomischen Rechen-Instituts. Bibcode:1969VeARI..22....1G.
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