Astronomy:Alpha Lyncis

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Short description: Star in the constellation Lynx
α Lyncis
Location of α Lyncis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lynx
Right ascension  09h 21m 03.30021s[1]
Declination +34° 23′ 33.2134″[1]
Apparent magnitude (V) +3.14[2]
Characteristics
Evolutionary stage Giant star
Spectral type K7 III[3]
U−B color index +1.95[4]
B−V color index +1.55[4]
Astrometry
Radial velocity (Rv)37.15[5] km/s
Proper motion (μ) RA: −218.723[1] mas/yr
Dec.: 16.555[1] mas/yr
Parallax (π)14.7 ± 0.18[1] mas
Distance220.7+2.9
−2.6 ly
(67.7+0.9
−0.8 pc)
Absolute bolometric
magnitude (Mbol)		–2.32 ± 0.13[6]
Details
Mass1.52±0.077[7] M☉
Radius58.15+0.73
−0.75[8] R☉
Luminosity621.1±15.8[7] L☉
Surface gravity (log g)1.06±0.04[7] cgs
Temperature3,881±20[7] K
Metallicity [Fe/H]−0.26±0.05[7] dex
Rotational velocity (v sin i)6.4[5] km/s
Age1.4[9] Gyr
Other designations
40 Lyncis, HR 3705, HD 80493, BD+35°1979, HIP 45860, SAO 61414, FK5 352, NSV 4456, GC 12880[10]
Database references
SIMBADdata

Alpha Lyncis (α Lyn, α Lyncis) is the brightest star in the northern constellation of Lynx with an apparent magnitude of +3.13.[4] Unusually, it is the only star in the constellation that has a Bayer designation.[9] Based upon parallax measurements, this star is located about 220 light-years (67 parsecs) from the Earth.[1]

Characteristics

This is a red giant star that has exhausted the hydrogen at its core and has evolved away from the main sequence. It has expanded to about 58 times the Sun's radius[8] and it is emitting roughly 621 times the luminosity of the Sun. The estimated effective temperature of the star's outer envelope is 3,881 K,[7] which is lower than the Sun's effective temperature of 5,778 K, and is giving Alpha Lyncis a red-orange hue that is characteristic of late K-type stars.[11]

Alpha Lyncis is a suspected small-amplitude red variable star[12] that changes apparent magnitude from +3.17 up to +3.12.[13] This variability pattern typically occurs in stars that have developed an inert carbon core surrounded by a helium-fusing shell, and suggests that Alpha Lyncis is starting to evolve into a Mira variable.[9]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode: 2002yCat.2237....0D. 
  3. ↑ Morgan, W. W.; Keenan, P. C. (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics 11: 29–50. doi:10.1146/annurev.aa.11.090173.000333. Bibcode: 1973ARA&A..11...29M. 
  4. ↑ 4.0 4.1 4.2 Johnson, H. L. et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (1): 99. Bibcode: 1966CoLPL...4...99J. 
  5. ↑ 5.0 5.1 Massarotti, A. et al. (2008). "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity". The Astronomical Journal 135 (1): 209–231. doi:10.1088/0004-6256/135/1/209. Bibcode: 2008AJ....135..209M. 
  6. ↑ Piau, L. et al. (2010). "Surface convection and red giants radii measurements". Astronomy and Astrophysics 526: 100. doi:10.1051/0004-6361/201014442. Bibcode: 2011A&A...526A.100P.  For Mbol, see Table 1.
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C. et al. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics 682: A145. doi:10.1051/0004-6361/202347136. ISSN 0004-6361. Bibcode: 2024A&A...682A.145S. https://ui.adsabs.harvard.edu/abs/2024A&A...682A.145S.  Alpha Lyncis' database entry at VizieR.
  8. ↑ 8.0 8.1 Baines, Ellyn K.; Armstrong, J. Thomas; Clark, James H.; Gorney, Jim; Hutter, Donald J.; Jorgensen, Anders M.; Kyte, Casey; Mozurkewich, David et al. (October 2021). "Angular Diameters and Fundamental Parameters of Forty-four Stars from the Navy Precision Optical Interferometer" (in en). The Astronomical Journal 162 (5): 198. doi:10.3847/1538-3881/ac2431. ISSN 1538-3881. Bibcode: 2021AJ....162..198B. 
  9. ↑ 9.0 9.1 9.2 Kaler, J. B. (May 11, 2005). "ALPHA LYN (Alpha Lyncis) and ALSCIAUKAT (31 Lyncis)". Stars. University of Illinois. http://stars.astro.illinois.edu/sow/alphalyn.html. 
  10. ↑ "Alpha Lyncis". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Alpha+Lyncis. 
  11. ↑ "The Colour of Stars". Australia Telescope Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html. 
  12. ↑ Percy, J. R. et al. (1994). "Photometric surveys of suspected small-amplitude red variables. III: An AAVSO photometric photometry survey". Publications of the Astronomical Society of the Pacific 106 (700): 611–615. doi:10.1086/133420. Bibcode: 1994PASP..106..611P. 
  13. ↑ Kukarkin, B. V. et al. (1981). "Catalogue of suspected variable stars". Nachrichtenblatt der Vereinigung der Sternfreunde E.V.. Bibcode: 1981NVS...C......0K. 
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Coordinates: Sky map 09h 21m 03s, +34° 23′ 33″



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