UX Lyncis

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]

  1. ^ a b Cite error: The named reference Percy 2001 was invoked but never defined (see the help page).
  2. ^ a b c d e f g h i j k Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference AAVSOUX was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Sloan_Price_1998 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Sato_Kuji_1990 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Lebzelter_Hron_2003 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Sinnott_Perryman_1997 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Walker1970 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Percy_et_al_2003 was invoked but never defined (see the help page).