Astronomy:Upsilon Ursae Majoris

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Short description: Binary star in the constellation Ursa Major
Upsilon Ursae Majoris
Ursa Major IAU.svg
Red circle.svg
Location of υ Ursae Majoris (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ursa Major
Right ascension  09h 50m 59.35700s[1]
Declination +59° 02′ 19.4486″[1]
Apparent magnitude (V) 3.68 – 3.86[2]
Characteristics
Spectral type F2 IV[3]
U−B color index +0.09[4]
B−V color index +0.29[4]
Variable type δ Sct[2]
Astrometry
Radial velocity (Rv)27.3±4.1[5] km/s
Proper motion (μ) RA: +42.97[1] mas/yr
Dec.: −23.62[1] mas/yr
Parallax (π)28.06 ± 0.20[1] mas
Distance116.2 ± 0.8 ly
(35.6 ± 0.3 pc)
Absolute magnitude (MV)+1.11[6]
Details
υ UMa A
Mass1.57[7] or 2.20[3] M☉
Radius2.79±0.40[8] R☉
Luminosity29.5[9] L☉
Surface gravity (log g)3.79±0.14[7] cgs
Temperature7,211±245[7] K
Rotation1.2±0.30 d[8]
Rotational velocity (v sin i)124.2[10] km/s
Age1.168[7] Gyr
υ UMa B
Mass0.44[3] M☉
Other designations
υ UMa, WDS J09510+5902[11]
A: 29 Ursae Majoris, BD+59°1268, FK5 368, HD 84999, HIP 48319, HR 3888, SAO 27401[11]
Database references
SIMBADdata

Upsilon Ursae Majoris, Latinized from υ Ursae Majoris, is a binary star[12] in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye with an apparent visual magnitude of +3.79.[4] Based upon an annual parallax shift of 13.24 mas,[1] it is located roughly 246 light-years from the Sun.

A light curve for Upsilon Ursae Majoris, plotted from TESS data[13]

The primary member of the system, component A, is an F-type subgiant star. It is a Delta Scuti variable[8] with a period of 0.1327 day and an amplitude of 0.050 magnitude.[14] With an estimated age of 1.168[7] billion years, it is spinning rapidly with a projected rotational velocity of 124.2 km/s[10] and a rotation period of 1.2 days.[8] The star has about 1.57[7] times the mass of the Sun and 2.79[8] times the Sun's radius. (De Rosa and colleagues give a mass estimate of 2.2[3] times the Sun's mass.) It is radiating around 29.5[9] times the solar luminosity from its outer atmosphere at an effective temperature of 7,211 K.[7]

The companion, component B, is a magnitude +11.0 star.[12] As of 2008, it has an angular separation of 11.78 arcseconds along a position angle of 295.4°. This corresponds to a projected separation of 419.8 AU.[3] It has a mass around 40% that of the Sun.[3]

Naming

With τ, h, φ, θ, e and f, it composed the Arabic asterism Sarīr Banāt al-Na'sh, the Throne of the daughters of Na'sh, and Al-Haud, the Pond.[15] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al-Haud were the title for seven stars : f as Alhaud I, τ as Alhaud II, e as Alhaud III, h as Alhaud IV, θ as Alhaud V, this star (υ) as Alhaud VI and φ as Alhaud VII .[16]

In Chinese, 文昌 (Wén Chāng), meaning Administrative Center, refers to an asterism consisting of υ Ursae Majoris, φ Ursae Majoris, θ Ursae Majoris, 15 Ursae Majoris and 18 Ursae Majoris. Consequently, the Chinese name for υ Ursae Majoris itself is 文昌一 (Wén Chāng yī, English: the first Star of Administrative Center.).[17]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 Samus, N. N. et al. (2009), "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)", VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1, Bibcode: 2009yCat....102025S. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 De Rosa, R. J. et al. (2013), "The VAST Survey – III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society 437 (2): 1216, doi:10.1093/mnras/stt1932, Bibcode: 2014MNRAS.437.1216D. 
  4. ↑ 4.0 4.1 4.2 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M. 
  5. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D. 
  6. ↑ Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics 542: A116, doi:10.1051/0004-6361/201118724, Bibcode: 2012A&A...542A.116A. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal 804 (2): 146, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Korzennik, S. G. et al. (April 1995), "Nightly variations of nonradial oscillations in the Delta Scuti star upsilon Ursae Majoris", Astrophysical Journal, Part 2 443 (1): L25–L28, doi:10.1086/187827, Bibcode: 1995ApJ...443L..25K. 
  9. ↑ 9.0 9.1 Balona, L. A.; Dziembowski, W. A. (October 1999), "Excitation and visibility of high-degree modes in stars", Monthly Notices of the Royal Astronomical Society 309 (1): 221–232, doi:10.1046/j.1365-8711.1999.02821.x, Bibcode: 1999MNRAS.309..221B. 
  10. ↑ 10.0 10.1 Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode: 2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 [yes|permanent dead link|dead link}}]
  11. ↑ 11.0 11.1 "ups UMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ups+UMa. 
  12. ↑ 12.0 12.1 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E. 
  13. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 8 December 2021. 
  14. ↑ Rodríguez, E. et al. (June 2000), "A revised catalogue of delta Sct stars", Astronomy and Astrophysics Supplement 144 (3): 469–474, doi:10.1051/aas:2000221, Bibcode: 2000A&AS..144..469R. 
  15. ↑ Allen, Richard Hinckley, Star-Names and Their Meanings, New York: G. E. Stechert, p. 442. 
  16. ↑ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf. 
  17. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 16 日



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