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UX Lyncis

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UX Lyncis

A visual band light curve for UX Lyncis. The top panel shows the variation over a period of years, and the lower plot shows the variation over a period of months. Adapted from Percy and Wilson (2001)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 09h 03m 47.10789s[2]
Declination +38° 44′ 31.6542″[2]
Apparent magnitude (V) 6.6 - 6.78[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M3III[5] or M6III[6]
B−V color index 1.356±0.011[7]
Variable type SRb:[4]
Astrometry
Radial velocity (Rv)+38.60±0.64[7] km/s
Proper motion (μ) RA: −17.176[2] mas/yr
Dec.: −20.823[2] mas/yr
Parallax (π)3.6035 ± 0.4422 mas[2]
Distanceapprox. 900 ly
(approx. 280 pc)
Absolute bolometric
magnitude
 (Mbol)
−0.15[7]
Details
Radius128.38+0.92
−9.89
[2] R
Luminosity1,766±242[2] L
Temperature3302+135
−11
[2] K
Other designations
UX Lyn, BD+39°2193, HD 77443, HIP 44481, SAO 61226, IRAS 09005+3856[8]
Database references
SIMBADdata

UX Lyncis is a variable star in the faint northern constellation of Lynx, positioned about 3° to the south of the 4th magnitude star 10 Ursae Majoris.[9] This is a red-hued star near the lower threshold of visibility to the naked eye, having an apparent visual magnitude that fluctuates around 6.70.[7] It is located at a distance of approximately 900 light years from the Sun based on parallax,[2] and is drifting further away with a radial velocity of +39 km/s.[7]

The stellar classification of this star is M3III,[5] while the infrared spectrum matches a class of M6III.[6] It is an aging red giant on the asymptotic giant branch that has exhausted the supply of both hydrogen and helium in its core, then cooled and expanded. At present it has 128[2] times the radius of the Sun, which is equivalent to 0.60 AU or 60% of the distance from the Sun to the Earth. On average, it radiates a luminosity approximately 1,766 times that of the Sun from its swollen photosphere at an effective temperature of 3,302 K.[2] Infrared observations show little or no evidence for an oxygen-rich dusty shell around the star.[4]

The variability of this star was reported by R. L. Walker in 1970 from the U.S. Naval Observatory.[10] UX Lyncis has been classified as a semiregular variable ranging from magnitude 6.6 down to 6.78.[3] Its changes in brightness are complex, with a shorter period of 37.3 days due to the star's pulsations, and a longer period of 420 days possibly due to the star's rotation or convectively induced oscillatory thermal (COT) mode.[1] There is some evidence for an additional weak variability with a 29 day period.[11]

References

[edit]
  1. ^ a b Percy, John R.; et al. (2001). "Long-Term VRI Photometry of Small-Amplitude Red Variables. I. Light Curves and Periods". The Publications of the Astronomical Society of the Pacific. 113 (786): 983–96. Bibcode:2001PASP..113..983P. doi:10.1086/322153.
  2. ^ a b c d e f g h i j k 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. ^ a b Watson, Christopher (4 January 2010). "UX Lyncis". AAVSO Website. American Association of Variable Star Observers. Retrieved 10 March 2016.
  4. ^ a b c Sloan, G. C.; Price, S. D. (December 1998). "The Infrared Spectral Classification of Oxygen-rich Dust Shells". The Astrophysical Journal Supplement Series. 119 (2): 141–158. Bibcode:1998ApJS..119..141S. doi:10.1086/313156.
  5. ^ a b Sato, K.; Kuji, S. (November 1990). "MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington". Astronomy & Astrophysics Supplement Series. 85: 1069. Bibcode:1990A&AS...85.1069S.
  6. ^ a b Lebzelter, T.; Hron, J. (December 2003). "Technetium and the third dredge up in AGB stars. I. Field stars". Astronomy and Astrophysics. 411 (3): 533–542. arXiv:astro-ph/0310018. Bibcode:2003A&A...411..533L. doi:10.1051/0004-6361:20031458. S2CID 18879265.
  7. ^ a b c d e Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  8. ^ "UX Lyn". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-22.
  9. ^ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 2. Sky Publishing Corporation and the European Space Agency. p. 620. ISBN 0-933346-83-2.
  10. ^ Walker, R. L. (July 1970). "Light Variations of BD+39°2193". Information Bulletin on Variable Stars. 447: 1. Bibcode:1970IBVS..447....1W.
  11. ^ Percy, John R.; et al. (April 2003). "Multiperiodicity in Five Small-Amplitude Pulsating Red Giants". The Publications of the Astronomical Society of the Pacific. 115 (806): 479–483. Bibcode:2003PASP..115..479P. doi:10.1086/374199. S2CID 120018973.