TU Ursae Majoris

TU Ursae Majoris

A light curve for TU Ursae Majoris, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 11h 29m 48.489s[2]
Declination +30° 04′ 02.38″[2]
Apparent magnitude (V) 10.03[3] (9.26 to 10.24)[4]
Characteristics
Spectral type kA2hA9.5 (phase 0.03)
kF0hF7.5 (phase 0.56)[5]
B−V color index 0.355±0.034[3]
Variable type RRab[4]
Astrometry
Radial velocity (Rv)98.50±2.1[6] km/s
Proper motion (μ) RA: −69.141 mas/yr[2]
Dec.: −53.426 mas/yr[2]
Parallax (π)1.5641 ± 0.0252 mas[2]
Distance2,090 ± 30 ly
(640 ± 10 pc)
Absolute magnitude (MV)0.66[7]
Details
Mass0.55[8] M☉
Radius4.93[9] R☉
Luminosity44.7[7] L☉
Surface gravity (log g)2.10±0.15[10] cgs
Temperature6,200±65[10] K
Metallicity [Fe/H]−1.31[10] dex
Rotational velocity (v sin i)12.76[11] km/s
Other designations
TU Uma, BD+30 2162, HIP 56088, SAO 62578, PPM 75904[12]
Database references
SIMBADdata

TU Ursae Majoris is a variable star in the northern circumpolar constellation of Ursa Major. It is classified as a Bailey-type 'ab' RR Lyrae variable with a period of 0.557648 days[13] that ranges in brightness from apparent visual magnitude of 9.26 down to 10.24.[4] The distance to this star is approximately 2,090 light years based on parallax measurements.[9] It is located near the north galactic pole at a distance that indicates this is a member of the galactic halo.[14]

The periodic variability of this star was discovered by P. Guthnick and R. Prager in 1929.[15][8] Its relative brightness has made this star the subject of regular observation since its discovery,[16] both photographically and then photoelectrically starting in 1957.[17] It was initially classed as a Bailey-type "a" RR Lyrae variable. The variations were found to be somewhat similar to RR Lyrae, with the periodicity of TU UMa differing by less than 1% of a day.[16] However, no evidence of a long-period modulation, known as the Blazhko effect, was found in this star.[17]

In 1990, A. Saha and R. E. White found variations in radial velocity over time that suggested this is a binary system.[14] However, confirmation of this proved difficult because of the distance and the pulsational behavior of the variable.[8] The system shows significant evidence of proper motion acceleration from a binary interaction.[18] Analysis of long-term oscillatory variations suggests an orbital period of 23.3 years and an eccentricity of 0.79,[19] with the secondary having at least 33% of the mass of the Sun.[8]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference GaiaEDR3 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Samus_et_al_2017 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference suntzeff1994 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Pena_et_al_2008 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Liška_et_al_2016 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Pancino_et_al_2015 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference apogee was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Hajdu_et_al_2018 was invoked but never defined (see the help page).
  14. ^ a b Cite error: The named reference Saha_White_1990 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Guthnick_Prager_1929 was invoked but never defined (see the help page).
  16. ^ a b Cite error: The named reference Preston_et_al_1961 was invoked but never defined (see the help page).
  17. ^ a b Cite error: The named reference Szeidl_et_al_1986 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Kervella_et_al_2019 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Wade_et_al_1999 was invoked but never defined (see the help page).