Astronomy:HD 166

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Short description: Star in the constellation Andromeda
HD 166
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A light curve for V439 Andromedae, plotted from TESS data,[1] with the 6.23 day rotation period shown in red,
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  00h 06m 36.7841s[2]
Declination +29° 01′ 17.4103″[2]
Apparent magnitude (V) 6.13 – 6.17[3]
Characteristics
Spectral type K0Ve[3][4]
U−B color index +0.30[5]
B−V color index +0.755[5]
Variable type BY Dra[3]
Astrometry
Radial velocity (Rv)−6.9±0.2[4] km/s
Proper motion (μ) RA: 380.092±0.060[2] mas/yr
Dec.: −177.573±0.037[2] mas/yr
Parallax (π)72.5764 ± 0.0498[2] mas
Distance44.94 ± 0.03 ly
(13.779 ± 0.009 pc)
Absolute magnitude (MV)5.41[6]
Details
Mass0.889[7] M☉
Radius0.9172±0.0090[7] R☉
Luminosity0.6078±0.0099[7] L☉
Surface gravity (log g)4.49±0.09[8] cgs
Temperature5509±34[8] K
Metallicity [Fe/H]0.00±0.03[8] dex
Rotation6.23±0.01 days[9]
Rotational velocity (v sin i)4.1 [9] km/s
Age78±28[8] Myr
Other designations
BD+28°4704, GC 95, GSC 01735-02532, GSC 01735-00927, Gliese 5, HD 166, HIP 544, HR 8, SAO 73743, PPM 89410, NSV 33, V439 Andromedae
Database references
SIMBADdata

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, varying between magnitudes 6.13 and 6.18 with a 6.23 days periodicity.[3] It appears within one degree of the star Alpha Andromedae[10] and is a member of the Hercules-Lyra association moving group.[4] It also happens to be less than 2 degrees from right ascension 00h 00m.

Star characteristics

HD 166 is a K-type main sequence star, cooler and dimmer than the Sun, and has a stellar classification of K0Ve[3] where the e suffix indicates the presence of emission lines in the spectrum. The star has a proper motion of 0.422 arcseconds per year in a direction 114.1° from north. It has an estimated visual luminosity of 61% of the Sun,[7] and is emitting like a blackbody with an effective temperature of 5,327K.[8] It has a diameter that is about 90% the size of the Sun[7] and a radial velocity of −6.9 km/s.[4] Age estimates range from as low as 78 million years old based on its chromospheric activity,[8] up to 9.6 billion years based on a comparison with theoretical evolutionary tracks.[7] 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 HD 166, 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]

Variability

Eric J. Gaidos et al. first detected variability in HD 166 in the year 2000.[9] It was given its variable star designation, V439 Andromedae, in 2006.[13] It has been found that the periodicity in the photometric variability of HD 166 is coincident with the rotation period.[9] This leads to its classification as a BY Draconis variable, where brightness variations are caused by the presence of large starspots on the surface and by chromospheric activity.

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 "V439 And database entry". Combined General Catalog of Variable Stars. CDS. http://webviz.u-strasbg.fr/viz-bin/VizieR-S?V*%20V0439%20And. 
  4. ↑ 4.0 4.1 4.2 4.3 López-Santiago, J.; Montes, D.; Crespo-Chacón, I.; Fernández-Figueroa, M. J. (2006). "The Nearest Young Moving Groups". The Astrophysical Journal 643 (2): 1160–1165. doi:10.1086/503183. Bibcode: 2006ApJ...643.1160L. 
  5. ↑ 5.0 5.1 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD: 0, Bibcode: 1986EgUBV........0M 
  6. ↑ 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, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 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, doi:10.1088/0004-637X/771/1/40, Bibcode: 2013ApJ...771...40B. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 Rich, Evan A.; Wisniewski, John P.; McElwain, Michael W.; Hashimoto, Jun; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Okamoto, Yoshiko K.; Abe, Lyu et al. (2017). "The fundamental stellar parameters of FGK stars in the SEEDS survey Norman, OK 73071, USA". Monthly Notices of the Royal Astronomical Society 472 (2): 1736. doi:10.1093/mnras/stx2051. Bibcode: 2017MNRAS.472.1736R. 
  9. ↑ 9.0 9.1 9.2 9.3 Gaidos (2000). "Spectroscopy and Photometry of Nearby Young Solar Analogs". The Astronomical Journal 120 (2): 1006–1013. doi:10.1086/301488. Bibcode: 2000AJ....120.1006G. 
  10. ↑ Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
  11. ↑ 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 
  12. ↑ Eiroa, C. et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics 555: A11. doi:10.1051/0004-6361/201321050. Bibcode: 2013A&A...555A..11E. 
  13. ↑ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (August 2006). "The 78th Name-List of Variable Stars". Information Bulletin on Variable Stars 5721: 1–45. Bibcode: 2006IBVS.5721....1K. https://ibvs.konkoly.hu/pub/ibvs/5701/5721.pdf. Retrieved 6 November 2024. 



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