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TU Ursae Majoris

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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]

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

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]

References

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  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. ^ a b 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.
  4. ^ a b c Samus', N. N; et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  5. ^ Suntzeff, Nicholas B.; et al. (1994), "Summary of Delta S Metallicity Measurements for Bright RR Lyrae Variables Observed at Lick Observatory and KPNO between 1972 and 1987", The Astrophysical Journal Supplement Series, 93: 271, Bibcode:1994ApJS...93..271S, doi:10.1086/192055.
  6. ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  7. ^ a b Pena, J. H.; et al. (December 2008), "Physical parameters determination of the RR Lyrae stars RU Psc, SS Psc and TU UMa", Communications in Asteroseismology, 157: 357–358, Bibcode:2008CoAst.157..357P.
  8. ^ a b c d Liška, J.; et al. (May 2016), "New analysis of the light time effect in TU Ursae Majoris", Astronomy & Astrophysics, 589: 13, arXiv:1502.03331, Bibcode:2016A&A...589A..94L, doi:10.1051/0004-6361/201525870, S2CID 54205554, A94.
  9. ^ a b 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.
  10. ^ a b c Pancino, E.; Britavskiy, N.; Romano, D.; Cacciari, C.; Mucciarelli, A.; Clementini, G. (March 2015), "Chemical abundances of solar neighbourhood RR Lyrae stars", Monthly Notices of the Royal Astronomical Society, 447 (3): 2404–2419, arXiv:1412.4580, Bibcode:2015MNRAS.447.2404P, doi:10.1093/mnras/stu2616.
  11. ^ Jönsson, Henrik; et al. (2020), "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South", The Astronomical Journal, 160 (3): 120, arXiv:2007.05537, Bibcode:2020AJ....160..120J, doi:10.3847/1538-3881/aba592, S2CID 220496397.
  12. ^ "TU UMa", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-25.
  13. ^ Hajdu, Gergely; et al. (April 2018), "A Data-driven Study of RR Lyrae Near-IR Light Curves: Principal Component Analysis, Robust Fits, and Metallicity Estimates", The Astrophysical Journal, 857 (1): 16, arXiv:1804.01456, Bibcode:2018ApJ...857...55H, doi:10.3847/1538-4357/aab4fd, S2CID 119458155, 55.
  14. ^ a b Saha, A.; White, R. E. (February 1990), "A New Velocity Curve of the RR Lyrae Star TU Ursae Majoris: Evidence for Duplicity", Publications of the Astronomical Society of the Pacific, 102: 148, Bibcode:1990PASP..102..148S, doi:10.1086/132621, S2CID 119405334
  15. ^ Guthnick, P.; Prager, R. (December 1929), "Benennung von veränderlichen Sternen", Astronomische Nachrichten, 237 (10): 169, Bibcode:1929AN....237..169G, doi:10.1002/asna.19292371002.
  16. ^ a b Preston, George W.; et al. (March 1961), "The Light and Radial-Velocity Variations of TU Ursae Majoris", Astrophysical Journal, 133: 484, Bibcode:1961ApJ...133..484P, doi:10.1086/147051.
  17. ^ a b Szeidl, B.; et al. (January 1986), "Period Changes of RR Lyrae Stars II, TW Her, WZ Her, AV Peg and TU UMa", Communications of the Konkoly Observatory, X (89): 57–110, Bibcode:1986CoKon..89...57S.
  18. ^ Kervella, P.; et al. (2019), "Binarity from Gaia DR2 and Hipparcos proper motion anomaly and common proper motion", Memorie della Societa Astronomica Italiana, 90: 340, Bibcode:2019MmSAI..90..340K.
  19. ^ Wade, Richard A.; et al. (November 1999), "A Timing Model for the RR Lyrae Variable Star TU Ursae Majoris, a Probable Member of a Binary System", The Astronomical Journal, 118 (5): 2442–2450, Bibcode:1999AJ....118.2442W, doi:10.1086/301109, S2CID 122188784.

Further reading

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  • Peña, J. H.; et al. (October 2012), "Strömgren uvby-beta photoelectric photometry of the variable stars RU Psc, SS Psc and TU UMa", Revista Mexicana de Astronomía y Astrofísica, 48: 299–303, Bibcode:2012RMxAA..48..299P.
  • Donley, J.; et al. (May 2002), "Light Maxima of the RRab Variable TU UMa in Early 2002", Information Bulletin on Variable Stars, 5273 (1): 1, Bibcode:2002IBVS.5273....1D.
  • Kiss, L. L.; et al. (June 1995), "A New Orbit of the Binary RR Lyrae Star TU UMa", Information Bulletin on Variable Stars, 4205 (1): 1, Bibcode:1995IBVS.4205....1K.
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