HD 166
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 00h 06m 36.78482s[2] |
| Declination | +29° 01′ 17.4038″[2] |
| Apparent magnitude (V) | 6.09[3] |
| Characteristics | |
| Spectral type | G8V[4] |
| U−B color index | +0.30[3] |
| B−V color index | +0.755[3] |
| Variable type | BY Dra[5] |
| Astrometry | |
| Radial velocity (Rv) | −6.59[6] km/s |
| Proper motion (μ) | RA: 380.98 ± 0.57[2] mas/yr Dec.: −178.68 ± 0.29[2] mas/yr |
| Parallax (π) | 73.15 ± 0.56[2] mas |
| Distance | 44.6 ± 0.3 ly (13.7 ± 0.1 pc) |
| Details | |
| Mass | 0.889[4] M☉ |
| Radius | 0.9172 ± 0.0090[4] R☉ |
| Luminosity | 0.6078 ± 0.0099[4] L☉ |
| Temperature | 5,327 ± 39[4] K |
| Metallicity [Fe/H] | 0.08[4] dex |
| Rotation | 6.23 ± 0.01 days[7] |
| Age | 9.6[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 166 or V439 Andromedae (ADS 69 A) is a 6th magnitude star in the constellation Andromeda, approximately 45 light years away from Earth. It is a variable star of the BY Draconis type,[5] with a variation in brightness smaller than 0.2 magnitude. This is a G-type main sequence star like the Sun, yet cooler and dimmer, having a stellar classification of G8V and an effective temperature of 5,327 kelvin.[4] It appears within one degree of the star Alpha Andromedae.[8]
The star has a proper motion of 0.422 arcsecond per year (114.1° from north). It has an estimated visual luminosity of 61% of Sol. It has a diameter that is about 0.9 × Sol and has a radial velocity of -6.6 km/s. Age estimates range from as low as 200 million years old based on its chromospheric activity,[9] up to 9.6[4] billion years. X-ray emission has been detected from this star, with an estimated luminosity of 8.5 × 1028 erg s−1.[10]
An infrared excess has been detected around this star, most likely indicating the presence of a circumstellar disk at a radius of 7.5 AU. The temperature of this dust is 90 K.[11]
References
- ↑ "Simbad Query Result". Simbad. Retrieved October 12, 2007.
- 1 2 3 4 5 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.Vizier catalog entry - 1 2 3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data. SIMBAD, Bibcode:1986EgUBV........0M
- 1 2 3 4 5 6 7 8 9 Boyajian, Tabetha S.; et al. (July 2013), "Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations", The Astrophysical Journal, 771 (1): 40, arXiv:1306.2974, Bibcode:2013ApJ...771...40B, doi:10.1088/0004-637X/771/1/40.
- 1 2 Kazarovets; et al. (2006-08-08). "The 78th Name-List of Variable Stars". The Information Bulletin on Variable Stars Number 5721. Konkoly Observatory. Retrieved 2010-03-01.
- ↑ Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477, Bibcode:2002ApJS..141..503N, doi:10.1086/340570.
- ↑ Gaidos; et al. (2000). "Spectroscopy and Photometry of Nearby Young Solar Analogs". The Astronomical Journal. 120 (2): 1006–1013. Bibcode:2000AJ....120.1006G. doi:10.1086/301488.
- ↑ Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
- ↑ Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
- ↑ Micela, G.; Favata, F.; Sciortino, S. (October 1997), "HIPPARCOS distances of X-ray selected stars: implications on their nature as stellar population", Astronomy and Astrophysics, 326: 221–227, Bibcode:1997A&A...326..221M
- ↑ Eiroa, C.; et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics. 555: A11. arXiv:1305.0155. Bibcode:2013A&A...555A..11E. doi:10.1051/0004-6361/201321050.