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HD 166

A light curve for V439 Andromedae, plotted from TESS data, with the 6.23 day rotation period shown in red,
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Andromeda
Right ascension	00 06 36.7841
Declination	+29° 01′ 17.4103″
Apparent magnitude (V)	6.13 – 6.17
Characteristics
Spectral type	K0Ve
U−B color index	+0.30
B−V color index	+0.755
Variable type	BY Dra
Astrometry
Radial velocity (Rv)	−6.9±0.2 km/s
Proper motion (μ)	RA: 380.092±0.060 mas/yr Dec.: −177.573±0.037 mas/yr
Parallax (π)	72.5764 ± 0.0498 mas
Distance	44.94 ± 0.03 ly (13.779 ± 0.009 pc)
Absolute magnitude (MV)	5.41
Details
Mass	0.889 M☉
Radius	0.9172±0.0090 R☉
Luminosity	0.6078±0.0099 L☉
Surface gravity (log g)	4.49±0.09 cgs
Temperature	5509±34 K
Metallicity	0.00±0.03 dex
Rotation	6.23±0.01 days
Rotational velocity (v sin i)	4.1  km/s
Age	78±28 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
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. It appears within one degree of the star Alpha Andromedae and is a member of the Hercules-Lyra association moving group. 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 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, and is emitting like a blackbody with an effective temperature of 5,327K. It has a diameter that is about 90% the size of the Sun and a radial velocity of −6.9 km/s. Age estimates range from as low as 78 million years old based on its chromospheric activity, up to 9.6 billion years based on a comparison with theoretical evolutionary tracks. X-ray emission has been detected from this star, with an estimated luminosity of 8.5×10 erg s.

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.

Variability

Eric J. Gaidos et al. first detected variability in HD 166 in the year 2000. It was given its variable star designation, V439 Andromedae, in 2006. It has been found that the periodicity in the photometric variability of HD 166 is coincident with the rotation period. 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. Retrieved 26 August 2024.
2. ^ 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.
3. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. 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. arXiv:1305.0155. Bibcode:2013A&A...555A..11E. doi:10.1051/0004-6361/201321050. S2CID 377244.
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" (PDF). Information Bulletin on Variable Stars. 5721: 1–45. Bibcode:2006IBVS.5721....1K. Retrieved 6 November 2024.

External links

• Image HD 166
• nstars.nau.edu

v t e Constellation of Andromeda
Adhil Andromeda in Chinese astronomy List of Andromeda's satellite galaxies List of stars in Andromeda
Stars	Bayer α (Alpheratz) β (Mirach) γ (Almach) δ ε ζ η θ ι κ λ μ ν ξ (Adhil) ο π ρ σ τ υ (Titawin) φ χ ψ ω A b c υ Per (Nembus) Flamsteed 2 3 4 5 6 7 8 9 10 11 12 13 14 (Veritate) 15 18 22 23 26 28 32 36 39 41 44 45 47 55 56 58 59 63 64 65 66 6 Per Variable R T U W Z RT RV RX SU SW TU TW WZ XZ AB AC AD AE AF AR BM BX CC CG CN DS DX EG ET EU FF GO GP GQ GX GR GY HH HN IW KK KX KZ LL LN LP LQ OP OS OU PX PY QR QV QX V385 V428 V439 V455 V529 V807 HR 1 40 56 78 104 122 134 178 275 282 283 289 379 410 483 687 746 748 8884 8925 8950 8962 8973 9011 9074 9075 9105 HD 16175 (Buna) 222155 Other 3XMM J004232.1+411314 ADS 48 HAT-P-6 (Sterrennacht) HAT-P-16 HAT-P-19 HAT-P-28 M31-RV KELT-1 NGC 44 NGC 82 NGC 84 NGC 91 NGC 162 NGC 464 Qatar-3 Qatar-4 Qatar-5 PA-99-N2 WASP-1 WISE 0146+4234 WISE J0005+3737 WISE J004945.61+215120.0
Exoplanets 14 Andromedae b κ Andromedae b υ Andromedae b c d Gliese 15 Ab c HD 13931 b HD 16175 b HAT-P-6b HAT-P-32b WASP-1b WASP-33b Qatar-4b Qatar-5b
Star clusters	NGC 206 272 752 956 7686 Other Mayall II RBC EXT8
Nebulae	NGC 7662
Galaxies	Messier 32 110 NGC 5 11 13 19 20 21 27 39 43 48 49 51 67 68 69 70 71 72 74 76 79 80 81 83 85 86 90 93 94 96 97 108 109 112 140 149 160 169 181 183 184 214 218 226 228 229 233 243 252 258 260 262 280 304 317 389 393 404 425 431 477 512 513 523 528 529 531 536 542 561 605 620 668 679 687 700 703 704 705 708 709 710 712 714 717 721 732 753 759 801 812 834 891 906 910 911 912 913 920 937 980 995 996 999 1000 7640 7836 Numbered I II III IV V VIII IX X XI XVIII XIX XXI Other 3C 66A 3C 66B Andromeda Galaxy Arp 273 Donatiello I UGC 1840
Galaxy clusters Abell 262 NGC 68 group
Astronomical events GRB 101225A SN 1885A (S)
Category

• Andromeda (constellation)
• BY Draconis variables
• Henry Draper Catalogue objects
• Spectroscopic binaries
• K-type main-sequence stars
• Solar-type stars
• Objects with variable star designations
• Bright Star Catalogue objects
• Hipparcos objects
• Durchmusterung objects
• Gliese and GJ objects
• Emission-line stars