Astronomy:36 Ursae Majoris

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Short description: Double star in the constellation Ursa Major
36 Ursae Majoris
Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000.0]]      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}}
Constellation Ursa Major
A
Right ascension  10h 30m 37.5793s[1]
Declination +55° 58′ 49.940″[1]
Apparent magnitude (V) 4.82[2]
B
Right ascension  10h 30m 25.3089s[3]
Declination +55° 59′ 56.855″[3]
Apparent magnitude (V) 8.86[4]
Characteristics
A
Evolutionary stage main sequence
Spectral type F8 V[5]
U−B color index −0.01[2]
B−V color index +0.52[2]
B
Evolutionary stage main sequence
Spectral type K7Ve[6]
B−V color index +1.34[7]
Astrometry
A
Radial velocity (Rv)+8.57[1] km/s
Proper motion (μ) RA: −177.045[1] mas/yr
Dec.: −32.634[1] mas/yr
Parallax (π)77.2485 ± 0.0805[1] mas
Distance42.22 ± 0.04 ly
(12.95 ± 0.01 pc)
Absolute magnitude (MV)4.29[8]
B
Radial velocity (Rv)+8.67[3] km/s
Proper motion (μ) RA: −182.443[3] mas/yr
Dec.: −32.034[1] mas/yr
Parallax (π)77.4072 ± 0.0182[3] mas
Distance42.135 ± 0.010 ly
(12.919 ± 0.003 pc)
Absolute magnitude (MV)8.2[7]
Details
A
Mass1.10[1] M☉
Radius1.17[1] R☉
Luminosity1.69[1] L☉
Surface gravity (log g)4.4.23[1] cgs
Temperature6,066[1] K
Metallicity [Fe/H]−0.09[9] dex
Rotational velocity (v sin i)1.50[9] km/s
Age4.0[1] Gyr
B
Mass0.626[4] M☉
Radius0.648[4] R☉
Luminosity0.10[10] L☉
Surface gravity (log g)4.61[4] cgs
Temperature4,132[10] K
Rotational velocity (v sin i)9[11] km/s
Age5[12] Gyr
Other designations
36 Ursae Majoris, WDS J10306+5559[5]
A: BD+56°1459, FK5 394, HD 90839, HIP 51459, HR 4112, SAO 27670
B: BD+56°1458, HD 237903, SAO 27668
Database references
SIMBADA
B

36 Ursae Majoris is a double star[5] in the northern constellation of Ursa Major. With an apparent visual magnitude of 4.8, it can be seen with the naked eye in suitable dark skies. Based upon parallax measurements, this binary lies at a distance of 42 light-years (13 parsecs) from Earth.

The brighter star of the two is a solar analog—meaning it has physical properties that make it similar to the Sun. It has 10% more mass and a radius 17% larger than the Sun, with an estimated age of four billion years. The spectrum of this star matches a stellar classification of F8 V, which indicates this is a main sequence star that is generating energy at its core through the nuclear fusion of hydrogen. The energy is being radiated into space from its outer envelope at an effective temperature of 6,066 K. This gives the star the characteristic yellow-white hue of an F-type star.[13]

The fainter of the two stars has an apparent magnitude 8.86 and shares a common proper motion witIts spectral type of K7Ve indicates it is a red dwarf. Its has a mass 60% of the Sun's, a temperature of 4,132 K and a bolometric luminosity only 1% of the Sun's.

36 Ursae Majoris has a second companion with a magnitude of 11.44 located at an angular separation of 240.6″ along a position angle of 292°, as of 2004.[14] It does not share the proper motion of the other two stars and is a more massive and luminous star but much further away.[15]

Hunt for substellar objects

According to Nelson & Angel (1998),[16] 36 Ursae Majoris could host one or two (or at least three) jovian planets (or even brown dwarfs) at wide separations from the host star, with orbital periods of 10–15, 25 and 50 years respectively. The authors have set upper limits of 1.1–2, 5.3 and 24 Jupiter masses for the putative planetary objects. Also Lippincott (1983)[17] had previously noticed the possible presence of a massive unseen companion (with nearly 70 times the mass of Jupiter, just below the stellar regime, thus a brown dwarf). Putative parameters for the substellar object show an orbital period of 18 years and quite a high eccentricity (e=0.8). Even Campbell et al. 1988[18] inferred the existence of planetary objects or even brown dwarfs less massive than 14 Jupiter masses around 36 Ursae Majoris.

Nevertheless, no certain planetary companion has yet been detected or confirmed. The McDonald Observatory team has set limits to the presence of one or more planets[19] with masses between 0.13 and 2.5 Jupiter masses and average separations spanning between 0.05 and 5.2 AU.

An infrared excess has been detected around this star, most likely indicating the presence of a circumstellar disk at a radius of 38.6 AU. The temperature of this dust is 50 K.[20]

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. ↑ 4.0 4.1 4.2 4.3 Stassun, Keivan G. et al. (9 September 2019), "The Revised TESS Input Catalog and Candidate Target List", The Astronomical Journal 158 (4): 138, doi:10.3847/1538-3881/ab3467, Bibcode: 2019AJ....158..138S. 
  5. ↑ 5.0 5.1 5.2 "HR 4112 -- Star in double system", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HR+4112, retrieved 2012-01-30 
  6. ↑ Deka-Szymankiewicz, B. et al. (2018), "The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample", Astronomy and Astrophysics 615: A31, doi:10.1051/0004-6361/201731696, Bibcode: 2018A&A...615A..31D. 
  7. ↑ 7.0 7.1 Boro Saikia, S. et al. (2018), "Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles", Astronomy and Astrophysics 616: A108, doi:10.1051/0004-6361/201629518, Bibcode: 2018A&A...616A.108B. 
  8. ↑ Nordström, B. et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics 418 (3): 989–1019, doi:10.1051/0004-6361:20035959, Bibcode: 2004A&A...418..989N 
  9. ↑ 9.0 9.1 Llorente de Andrés, F.; Chavero, C.; de la Reza, R.; Roca-Fàbrega, S.; Cifuentes, C. (October 2021), "The evolution of lithium in FGK dwarf stars", Astronomy & Astrophysics 654: A137, doi:10.1051/0004-6361/202141339, ISSN 0004-6361, Bibcode: 2021A&A...654A.137L. 
  10. ↑ 10.0 10.1 Gaidos, Eric; Mann, Andrew W. (August 2014), "M dwarf metallicities and giant planet occurrence: ironing out uncertainties and systematics", The Astrophysical Journal 791 (1): 9, doi:10.1088/0004-637X/791/1/54, 54, Bibcode: 2014ApJ...791...54G. 
  11. ↑ López-Valdivia, Ricardo; Mace, Gregory N.; Sokal, Kimberly R.; Hussaini, Maryam; Kidder, Benjamin T.; Mann, Andrew W.; Gosnell, Natalie M.; Oh, Heeyoung et al. (2019), "Effective Temperatures of Low-mass Stars from High-resolution H-band Spectroscopy", The Astrophysical Journal 879 (2): 105, doi:10.3847/1538-4357/ab2129, Bibcode: 2019ApJ...879..105L. 
  12. ↑ Richey-Yowell, Tyler; Shkolnik, Evgenya L.; Schneider, Adam C.; Osby, Ella; Barman, Travis; Meadows, Victoria S. (2019), "HAZMAT. V. The Ultraviolet and X-Ray Evolution of K Stars", The Astrophysical Journal 872 (1): 17, doi:10.3847/1538-4357/aafa74, Bibcode: 2019ApJ...872...17R. 
  13. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16 
  14. ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds, retrieved 2015-11-02. 
  15. ↑ Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  16. ↑ Nelson, A. F.; Angel, J. R. P. (June 1998), "The Range of Masses and Periods Explored by Radial Velocity Searches for Planetary Companions", The Astrophysical Journal 500 (2): 940–957, doi:10.1086/305741, Bibcode: 1998ApJ...500..940N. 
  17. ↑ Lippincott, S. L. (1983), "An unseen companion to 36 Ursae Majoris a from analysis of plates taken with the Sproul 61-cm refractor", Publications of the Astronomical Society of the Pacific 95: 775, doi:10.1086/131252, Bibcode: 1983PASP...95..775L. 
  18. ↑ Murdoch, Kaylene A.; Hearnshaw, J. B.; Clark, M. (August 1993), "A search for substellar companions to southern solar-type stars", Astrophysical Journal, Part 1 413 (1): 349–363, doi:10.1086/173003, Bibcode: 1993ApJ...413..349M. 
  19. ↑ Wittemeyer et al. (2006), "Detection Limits from the McDonald Observatory Planet Search Program", The Astronomical Journal 132 (1): 177–188, doi:10.1086/504942, Bibcode: 2006AJ....132..177W. 
  20. ↑ Eiroa, C. et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics 555: A11. doi:10.1051/0004-6361/201321050. Bibcode: 2013A&A...555A..11E. 

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