Astronomy:TU Ursae Majoris

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TU Ursae Majoris
TUUMaLightCurve.png
A light curve for TU Ursae Majoris, plotted from TESS data[1]
Observation data
Equinox J2000.0]] (ICRS)
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[2] mas/yr
Dec.: −53.426[2] mas/yr
Parallax (π)1.5641 ± 0.0252[2] mas
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]

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  2. ↑ 2.0 2.1 2.2 2.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  4. ↑ 4.0 4.1 4.2 Samus', N. N et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  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, doi:10.1086/192055, Bibcode: 1994ApJS...93..271S. 
  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, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G. 
  7. ↑ 7.0 7.1 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. ↑ 8.0 8.1 8.2 8.3 Liška, J. et al. (May 2016), "New analysis of the light time effect in TU Ursae Majoris", Astronomy & Astrophysics 589: 13, doi:10.1051/0004-6361/201525870, A94, Bibcode: 2016A&A...589A..94L. 
  9. ↑ 9.0 9.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  10. ↑ 10.0 10.1 10.2 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, doi:10.1093/mnras/stu2616, Bibcode: 2015MNRAS.447.2404P. 
  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, doi:10.3847/1538-3881/aba592, Bibcode: 2020AJ....160..120J. 
  12. ↑ "TU UMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=TU+UMa. 
  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, doi:10.3847/1538-4357/aab4fd, 55, Bibcode: 2018ApJ...857...55H. 
  14. ↑ 14.0 14.1 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, doi:10.1086/132621, Bibcode: 1990PASP..102..148S 
  15. ↑ Guthnick, P.; Prager, R. (December 1929), "Benennung von veränderlichen Sternen", Astronomische Nachrichten 237 (10): 169, doi:10.1002/asna.19292371002, Bibcode: 1929AN....237..169G. 
  16. ↑ 16.0 16.1 Preston, George W. et al. (March 1961), "The Light and Radial-Velocity Variations of TU Ursae Majoris", Astrophysical Journal 133: 484, doi:10.1086/147051, Bibcode: 1961ApJ...133..484P. 
  17. ↑ 17.0 17.1 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, doi:10.1086/301109, Bibcode: 1999AJ....118.2442W. 

Further reading

  • 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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