 A light curve for TU Ursae Majoris, plotted from TESS data | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 11 29 48.489 |
| Declination | +30° 04′ 02.38″ |
| Apparent magnitude (V) | 10.03 (9.26 to 10.24) |
| Characteristics | |
| Spectral type | kA2hA9.5 (phase 0.03) kF0hF7.5 (phase 0.56) |
| B−V color index | 0.355±0.034 |
| Variable type | RRab |
| Astrometry | |
| Radial velocity (Rv) | 98.50±2.1 km/s |
| Proper motion (μ) | RA: −69.141 mas/yr Dec.: −53.426 mas/yr |
| Parallax (π) | 1.5641 ± 0.0252 mas |
| Distance | 2,090 ± 30 ly (640 ± 10 pc) |
| Absolute magnitude (MV) | 0.66 |
| Details | |
| Mass | 0.55 M☉ |
| Radius | 4.93 R☉ |
| Luminosity | 44.7 L☉ |
| Surface gravity (log g) | 2.10±0.15 cgs |
| Temperature | 6,200±65 K |
| Metallicity | −1.31 dex |
| Rotational velocity (v sin i) | 12.76 km/s |
| Other designations | |
| TU Uma, BD+30 2162, HIP 56088, SAO 62578, PPM 75904 | |
| Database references | |
| SIMBAD | data |
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 that ranges in brightness from apparent visual magnitude of 9.26 down to 10.24. The distance to this star is approximately 2,090 light years based on parallax measurements. It is located near the north galactic pole at a distance that indicates this is a member of the galactic halo.
The periodic variability of this star was discovered by P. Guthnick and R. Prager in 1929. Its relative brightness has made this star the subject of regular observation since its discovery, both photographically and then photoelectrically starting in 1957. 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. However, no evidence of a long-period modulation, known as the Blazhko effect, was found in this star.
In 1990, A. Saha and R. E. White found variations in radial velocity over time that suggested this is a binary system. However, confirmation of this proved difficult because of the distance and the pulsational behavior of the variable. The system shows significant evidence of proper motion acceleration from a binary interaction. Analysis of long-term oscillatory variations suggests an orbital period of 23.3 years and an eccentricity of 0.79, with the secondary having at least 33% of the mass of the Sun.
References
- "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ 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.
- ^ 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.
- ^ 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.
- 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.
- 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- 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.
- "TU UMa", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-25.
- 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.
- ^ 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
- Guthnick, P.; Prager, R. (December 1929), "Benennung von veränderlichen Sternen", Astronomische Nachrichten, 237 (10): 169, Bibcode:1929AN....237..169G, doi:10.1002/asna.19292371002.
- ^ 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.
- ^ 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.
- 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.
- 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
- 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.
