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 ± 0.13[6] km/s |
Proper motion (μ) | RA: 380.98 ± 0.57[2] mas/yr Dec.: −178.68 ± 0.29[2] mas/yr |
Parallax (π) | 72.58 ± 0.05 mas[6] |
Distance | 44.94 ± 0.03 ly (13.778 ± 0.009 pc) |
Absolute magnitude (MV) | 5.41[7] |
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[8] |
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 5,327K.[4] It appears within one degree of the star Alpha Andromedae.[9]
The star has a proper motion of 0.422 arcseconds per year (114.1° from north). It has an estimated visual luminosity of 61% of the Sun. It has a diameter that is about 90% the size of the Sun 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,[10] 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.[11]
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.[12]
References
- ^ "HD 166". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 12, 2007.
- ^ a b c d 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
- ^ a b c Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data. SIMBAD, Bibcode:1986EgUBV........0M
- ^ a b c d e f g h i 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.
- ^ a b 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.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
- ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191.
- ^ Gaidos; et al. (2000). "Spectroscopy and Photometry of Nearby Young Solar Analogs". The Astronomical Journal. 120 (2): 1006–1013. Bibcode:2000AJ....120.1006G. CiteSeerX 10.1.1.43.4478. 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.