HD 166

Last updated
HD 166
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Andromeda
Right ascension 00h 06m 36.7841s [1]
Declination +29° 01′ 17.4103″ [1]
Apparent magnitude  (V)6.13 – 6.17 [2]
Characteristics
Spectral type K0Ve [2] [3]
U−B color index +0.30 [4]
B−V color index +0.755 [4]
Variable type BY Dra [2]
Astrometry
Radial velocity (Rv)−6.9±0.2 [3]  km/s
Proper motion (μ)RA: 380.092±0.060 [1]   mas/yr
Dec.: −177.573±0.037 [1]   mas/yr
Parallax (π)72.5764 ± 0.0498  mas [1]
Distance 44.94 ± 0.03  ly
(13.779 ± 0.009  pc)
Absolute magnitude  (MV)5.41 [5]
Details
Mass 0.889 [6]   M☉
Radius 0.9172±0.0090 [6]   R☉
Luminosity 0.6078±0.0099 [6]   L☉
Surface gravity (log g)4.49±0.09 [7]   cgs
Temperature 5509±34 [7]   K
Metallicity [Fe/H]0.00±0.03 [7]   dex
Rotation 6.23±0.01 days [8]
Rotational velocity (v sin i)4.1 [8]  km/s
Age 78±28 [7]   Myr
Other designations
BD+28°4704, GC 95, GSC 01735-02532, GSC 01735-00927, Gliese 5, HD 166, HIP  544, HR  8, SAO  73743, NSV 33
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. [2] It appears within one degree of the star Alpha Andromedae [9] and is a member of the Hercules-Lyra association moving group. [3] It also happens to be less than 2 degrees from right ascension 00h 00m.

Contents

Star characteristics

HD 166 is a K-type main sequence star, cooler and dimmer than the Sun, and has a stellar classification of K0Ve [2] 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, [6] and is emitting like a blackbody with an effective temperature of 5,327K. [7] It has a diameter that is about 90% the size of the Sun [6] and a radial velocity of −6.9 km/s. [3] Age estimates range from as low as 78 million years old based on its chromospheric activity, [7] up to 9.6 billion years based on a comparison with theoretical evolutionary tracks. [6] 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 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. [11]

Variability

It has been found that the periodicity in the photometric variability of HD 166 is coincident with the rotation period. [8] 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.

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<span class="mw-page-title-main">Gliese 105</span> Triple star system in the constellation Cetus

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<span class="mw-page-title-main">EQ Virginis</span> Star in the constellation Virgo

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<span class="mw-page-title-main">V538 Aurigae</span> Star in constellation Auriga

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<span class="mw-page-title-main">9 Ceti</span> Star in the constellation Cetus

9 Ceti is a star in the equatorial constellation of Cetus. It has the variable star designation BE Ceti, while 9 Ceti is the Flamsteed designation. It has an apparent visual magnitude of 6.4, which is below the limit that can be seen with the naked eye by a typical observer. Based upon parallax measurements, this star is 69.6 light years away from the Sun.

HD 215152 is the Henry Draper Catalogue designation for a star in the zodiac constellation of Aquarius. It has an apparent visual magnitude of 8.13, meaning it is too faint to be seen with the naked eye. Parallax measurements provide distance estimates of around 70 light years. The star has a relatively high proper motion, moving across the sky at an estimated 0.328 arc seconds per year along a position angle of 205°.

HD 195564 is the Henry Draper Catalogue designation for a star in the southern constellation of Capricornus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.65. Parallax measurements give us an estimate of its distance as 81 light years. This is a candidate wide binary system as a faint companion star shares a common proper motion with the brighter primary component.

HD 219623 is a solitary star in the northern circumpolar constellation of Cassiopeia. HD 219623 is its Henry Draper Catalogue designation. It has an apparent visual magnitude of 5.59, which lies in the brightness range that is visible to the naked eye. According to the Bortle scale, it can be observed from dark suburban skies. Parallax measurements place it at an estimated distance of around 67.2 light years. It has a relatively high proper motion, advancing 262 mas per year across the celestial sphere.

HD 119124 is a wide binary star system in the circumpolar constellation of Ursa Major. With an apparent visual magnitude of 6.3, it lies below the normal brightness limit of stars that are visible with the naked eye under most viewing conditions. An annual parallax shift of 39.24 mas for the A component provides a distance estimate of 83 light years. The pair are candidate members of the Castor Moving Group, which implies a relatively youthful age of around 200 million years. HD 119124 is moving closer to the Sun with a radial velocity of −12 km/s.

<span class="mw-page-title-main">LQ Hydrae</span> Star in the constellation Hydra

LQ Hydrae is a single variable star in the equatorial constellation of Hydra. It is sometimes identified as Gl 355 from the Gliese Catalogue; LQ Hydrae is the variable star designation, which is abbreviated LQ Hya. The brightness of the star ranges from an apparent visual magnitude of 7.79 down to 7.86, which is too faint to be readily visible to the naked eye. Based on parallax measurements, this star is located at a distance of 59.6 light years from the Sun. It is drifting further away with a radial velocity of 7.6 km/s.

HD 46815 is a solitary star in the southern constellation Columba. It is faintly visible to the naked eye with an apparent magnitude of 5.4 and is estimated to be 408 light years away. However, it is receding with a heliocentric radial velocity of 32.2 km/s.

References

  1. 1 2 3 4 5 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 . Gaia DR2 record for this source at VizieR.
  2. 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.
  3. 1 2 3 4 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.
  4. 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
  5. ↑ 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.
  6. 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.
  7. 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.
  8. 1 2 3 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.
  9. ↑ Autostar Suite Astronomer Edition. CD-ROM. Meade, April 2006.
  10. ↑ 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
  11. ↑ 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.
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