HD 166

Last updated
HD 166
Andromeda constellation map.svg
Red circle.svg
Location of HD 166 (circled in red)
Observation data
Epoch J2000.0       Equinox J2000.0
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]
Distance 44.90 ± 0.02  ly
(13.766 ± 0.006  pc)
Absolute magnitude  (MV)5.41 [6]
Details
Mass 0.889 [7]   M☉
Radius 0.9172±0.0090 [7]   R☉
Luminosity 0.6078±0.0099 [7]   L☉
Surface gravity (log g)4.49±0.09 [8]   cgs
Temperature 5509±34 [8]   K
Metallicity [Fe/H]0.00±0.03 [8]   dex
Rotation 6.23±0.01 days [9]
Rotational velocity (v sin i)4.1 [9]  km/s
Age 78±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
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, 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.

Contents

Star characteristics

A light curve for V439 Andromedae, plotted from TESS data, with the 6.23 day rotation period shown in red V439AndLightCurve.png
A light curve for V439 Andromedae, plotted from TESS data, 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

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

  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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