UX Lyncis
{{Short description|Star in the constellation Lynx}}
{{Starbox begin}}
{{Starbox image
| image = 250px
| caption = 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)
}}
{{Starbox observe
| epoch = J2000
| dec = {{DEC|+38|44|31.6542}}
| constell = Lynx
}}
{{Starbox character
| type = AGB
| class = M3III or M6III
| u-b =
| variable = SRb:
}}
{{Starbox astrometry
| radial_v = {{val|+38.60|0.64}}
| parallax = 3.6035
| p_error = 0.4422
}}
{{Starbox detail
| mass =
| radius = {{val|128.38|0.92|9.89}}
| luminosity = {{val|1766|242|fmt=commas}}
| gravity =
| temperature = {{val|3302|135|11}}
| metal_fe =
| rotational_velocity =
| age_gyr =
}}
{{Starbox catalog
| names = {{odlist | V=UX Lyn | HD=77443 | BD=+39°2193 | HIP=44481 | IRAS=09005+3856 | SAO=61226 }}
}}
{{Starbox reference
| Simbad=UX+Lyn
}}
{{Starbox end}}
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. 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. It is located at a distance of approximately 900 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +39 km/s.
The stellar classification of this star is M3III, while the infrared spectrum matches a class of M6III. 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 times the radius of the Sun, which is equivalent to {{convert|128.38|solar radius|AU|2|disp=out|lk=on|abbr=on}} 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. Infrared observations show little or no evidence for an oxygen-rich dusty shell around the star.
The variability of this star was reported by R. L. Walker in 1970 from the U.S. Naval Observatory. It was given its variable star designation in 1973. UX Lyncis has been classified as a semiregular variable ranging from magnitude 6.6 down to 6.78. 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. There is some evidence for an additional weak variability with a 29 day period.
References
{{reflist|30em|refs=
{{cite simbad | title=UX Lyn | accessdate=2021-01-22 }}
{{cite DR2|719225572598968832}}
| first1=Roger W. | last1=Sinnott
| first2=Michael A. C. | last2=Perryman
| title=Millennium Star Atlas | page=620
| volume=2 | year=1997 | isbn=0-933346-83-2
| publisher=Sky Publishing Corporation and the European Space Agency }}
| last1=Kukarkin | first1=B. V. | last2=Kholopov | first2=P. N.
| last3=Kukarkina | first3=N. P. | last4=Perova | first4=N. B. | title=59th Name-List of Variable Stars
| journal=Information Bulletin on Variable Stars | date=October 1973 | volume=834 |bibcode=1973IBVS..834....1K
| url=https://ibvs.konkoly.hu/pub/ibvs/0801/0834.pdf | access-date=21 December 2024}}
| title=Light Variations of BD+39°2193
| last=Walker | first=R. L.
| journal=Information Bulletin on Variable Stars
| volume=447 | page=1 | date=July 1970
| bibcode=1970IBVS..447....1W }}
| title=MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington.
| last1=Sato | first1=K. | last2=Kuji | first2=S.
| journal=Astronomy & Astrophysics Supplement Series
| volume=85 | page=1069 | date=November 1990
| bibcode=1990A&AS...85.1069S }}
| title=The Infrared Spectral Classification of Oxygen-rich Dust Shells
| last1=Sloan | first1=G. C. | last2=Price | first2=S. D.
| journal=The Astrophysical Journal Supplement Series
| volume=119 | issue=2 | pages=141–158 | date=December 1998
| doi=10.1086/313156 | bibcode=1998ApJS..119..141S | doi-access=free }}
| title=Technetium and the third dredge up in AGB stars. I. Field stars
| last1=Lebzelter | first1=T. | last2=Hron | first2=J.
| journal=Astronomy and Astrophysics
| volume=411 | pages=533–542 | date=December 2003
| issue=3 | arxiv=astro-ph/0310018 | bibcode=2003A&A...411..533L
| doi=10.1051/0004-6361:20031458 | s2cid=18879265 }}
| title=XHIP: An extended hipparcos compilation
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
| arxiv=1108.4971 | s2cid=119257644 }}
| title=Multiperiodicity in Five Small-Amplitude Pulsating Red Giants
| last1=Percy | first1=John R. | last2=Besla | first2=Gurtina
| last3=Velocci | first3=Vince | last4=Henry | first4=Gregory W.
| display-authors=1 | journal=The Publications of the Astronomical Society of the Pacific
| volume=115 | issue=806 | pages=479–483 | date=April 2003
| doi=10.1086/374199 | bibcode=2003PASP..115..479P | s2cid=120018973 | doi-access=free }}
| display-authors=1 | last1=Percy | first1=John R.
| last2=Wilson | first2=Joseph B. | last3=Henry | first3=Gregory W.
| title=Long-Term VRI Photometry of Small-Amplitude Red Variables. I. Light Curves and Periods
| journal=The Publications of the Astronomical Society of the Pacific
| volume=113 | issue=786 | pages=983–96 | date=2001
| bibcode=2001PASP..113..983P | doi=10.1086/322153 |doi-access=free }}
| url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=17933
| title=UX Lyncis
| last=Watson | first=Christopher | date=4 January 2010
| publisher=American Association of Variable Star Observers
| work=AAVSO Website | access-date=10 March 2016}}
}}
{{Stars of Lynx}}
{{DEFAULTSORT:UX Lyncis}}
Category:Semiregular variable stars