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// Workers AI · dad joke modeWhy did HD 166 go to therapy? It had stellar issues.

From Wikipedia, the free encyclopedia
HD 166
Location of HD 166 (circled in red)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Andromeda[1]
Right ascension 00h 06m 36.78401s[2]
Declination +29° 01′ 17.4127″[2]
Apparent magnitude (V) 6.13 – 6.17[3]
Characteristics
Evolutionary stage main sequence[2]
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)−6.75±0.12[2] km/s
Proper motion (μ) RA: 380.159 mas/yr[2]
Dec.: −177.730 mas/yr[2]
Parallax (π)72.6419±0.0292 mas[2]
Distance44.90 ± 0.02 ly
(13.766 ± 0.006 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
V439 And, NSV 33, BD+28°4704, GC 95, GJ 5, HD 166, HIP 544, HR 8, SAO 73743, PPM 89410, ADS 69 A, GSC 01735-00927, GSC 01735-02532
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

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A light curve for V439 Andromedae, plotted from TESS data,[11] with the 6.23 day rotation period shown in red

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.[12]

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.[13]

Variability

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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.[14] 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

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  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 4 5 N. N. Samus; O. V. Durlevich; et al. "V439 And database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2018-11-12.
  4. 1 2 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. arXiv:astro-ph/0601573. Bibcode:2006ApJ...643.1160L. doi:10.1086/503183. S2CID 119520529.
  5. 1 2 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, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  7. 1 2 3 4 5 6 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, S2CID 14911430.
  8. 1 2 3 4 5 6 Rich, Evan A.; Wisniewski, John P.; McElwain, Michael W.; Hashimoto, Jun; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Okamoto, Yoshiko K.; Abe, Lyu; Akiyama, Eiji; Brandner, Wolfgang; Brandt, Timothy D.; Cargile, Phillip; Carson, Joseph C.; Currie, Thayne M.; Egner, Sebastian; Feldt, Markus; Fukagawa, Misato; Goto, Miwa; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Hebb, Leslie; Hełminiak, Krzysztof G.; Henning, Thomas; Hodapp, Klaus W.; Ishii, Miki; Iye, Masanori; 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. arXiv:1708.02541. Bibcode:2017MNRAS.472.1736R. doi:10.1093/mnras/stx2051. S2CID 58942857.
  9. 1 2 3 4 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. S2CID 16930014.
  10. ↑ Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
  11. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 26 August 2024.
  12. ↑ 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
  13. ↑ 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. S2CID 377244.
  14. ↑ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (August 2006). "The 78th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 5721: 1–45. Bibcode:2006IBVS.5721....1K. Retrieved 6 November 2024.
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