Merak

Beta Ursae Majoris
	; Merak in Ursa Major
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Ursa Major
Right ascension	11h 01m 50.47654s
Declination	+56° 22′ 56.7339″
Apparent magnitude (V)	+2.37
Characteristics
Spectral type	A1IVps
U−B color index	+0.00
B−V color index	-0.02
Variable type	Suspected
Astrometry
Radial velocity (Rv)	-12.0 km/s
Proper motion (μ)	RA: +81.43 mas/yr ; Dec.: +33.49 mas/yr
Parallax (π)	40.90 ± 0.16 mas
Distance	79.7 ± 0.3 ly ; (24.45 ± 0.10 pc)
Absolute magnitude (MV)	+0.61
Details
Mass	2.7 M☉
Radius	3.021 ± 0.038 R☉
Luminosity	63.015 ± 1.307 L☉
Surface gravity (log g)	3.83 cgs
Temperature	9377 ± 75 K
Rotational velocity (v sin i)	46 km/s
Age	500 ± 100 Myr
Other designations
	Merak, Mirak, β Ursae Majoris, β UMa, Beta UMa, 48 Ursae Majoris, BD+57°1302, FK5 416, GC 15145, HD 95418, HIP 53910, HR 4295, PPM 32912, SAO 27876
Database references
SIMBAD	data

Merak or Beta Ursae Majoris is a star in the constellation Ursa Major. It is a white star three times larger than the Sun.^[7] It is a part of an asterism called the Big Dipper.

Related pages

List of brightest stars

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
↑ ^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
↑ Phillips, N. M.; Greaves, J. S.; Dent, W. R. F.; Matthews, B. C.; Holland, W. S.; Wyatt, M. C.; Sibthorpe, B. (2010). "Target selection for the SUNS and DEBRIS surveys for debris discs in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 403 (3): 1089. arXiv:0911.3426. Bibcode:2010MNRAS.403.1089P. doi:10.1111/j.1365-2966.2009.15641.x. S2CID 119262858.{{cite journal}}: CS1 maint: unflagged free DOI (link)
↑ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
↑ Eggen, Olin J. (August 1998), "The Sirius Supercluster and Missing Mass near the Sun", The Astronomical Journal, 116 (2): 782–788, Bibcode:1998AJ....116..782E, doi:10.1086/300465.
↑ Wyatt, M. C.; et al. (July 2007), "Steady State Evolution of Debris Disks around A Stars", The Astrophysical Journal, 663 (1): 365–382, arXiv:astro-ph/0703608, Bibcode:2007ApJ...663..365W, doi:10.1086/518404, S2CID 18883195
↑ ^7.0 ^7.1 ^7.2 ^7.3 Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101, S2CID 18993744. See Table 10.
↑ ^8.0 ^8.1 Monier, R. (November 2005), "Abundances of a sample of A and F-type dwarf members of the Ursa Major Group", Astronomy and Astrophysics, 442 (2): 563–566, Bibcode:2005A&A...442..563M, doi:10.1051/0004-6361:20053222
↑ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298
↑ Allen, Richard Hinckley (1899), "Star-names and their meanings", New York, G. E. Stechert: 438, Bibcode:1899sntm.book.....A
↑ "MERAK -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-01

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[aaa474_2_653-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.

[clpl4_99-2] 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

[phillips-3] Phillips, N. M.; Greaves, J. S.; Dent, W. R. F.; Matthews, B. C.; Holland, W. S.; Wyatt, M. C.; Sibthorpe, B. (2010). "Target selection for the SUNS and DEBRIS surveys for debris discs in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 403 (3): 1089. arXiv:0911.3426. Bibcode:2010MNRAS.403.1089P. doi:10.1111/j.1365-2966.2009.15641.x. S2CID 119262858.{{cite journal}}: CS1 maint: unflagged free DOI (link)

[rgcrv-4] Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.

[Eggen1998-5] Eggen, Olin J. (August 1998), "The Sirius Supercluster and Missing Mass near the Sun", The Astronomical Journal, 116 (2): 782–788, Bibcode:1998AJ....116..782E, doi:10.1086/300465.

[apj663_1_365-6] Wyatt, M. C.; et al. (July 2007), "Steady State Evolution of Debris Disks around A Stars", The Astrophysical Journal, 663 (1): 365–382, arXiv:astro-ph/0703608, Bibcode:2007ApJ...663..365W, doi:10.1086/518404, S2CID 18883195

[apj746_1_101-7] 7.0 ^7.1 ^7.2 ^7.3 Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101, S2CID 18993744. See Table 10.

[aaa442_2_563-8] 8.0 ^8.1 Monier, R. (November 2005), "Abundances of a sample of A and F-type dwarf members of the Ursa Major Group", Astronomy and Astrophysics, 442 (2): 563–566, Bibcode:2005A&A...442..563M, doi:10.1051/0004-6361:20053222

[aaa463_2_671-9] Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298

[allen1899-10] Allen, Richard Hinckley (1899), "Star-names and their meanings", New York, G. E. Stechert: 438, Bibcode:1899sntm.book.....A

[SIMBAD-11] "MERAK -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-01

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Observation data Epoch J2000.0 Equinox J2000.0
Merak in Ursa Major
Constellation	Ursa Major
Right ascension	11^h 01^m 50.47654^s^[1]
Declination	+56° 22′ 56.7339″^[1]
Apparent magnitude (V)	+2.37^[2]
Characteristics
Spectral type	A1IVps^[3]
U−B color index	+0.00^[2]
B−V color index	-0.02^[2]
Variable type	Suspected
Astrometry

Radial velocity (R_v)	-12.0^[4] km/s
Proper motion (μ)	RA: +81.43^[1] mas/yr Dec.: +33.49^[1] mas/yr
Parallax (π)	40.90 ± 0.16^[1] mas
Distance	79.7 ± 0.3 ly (24.45 ± 0.10 pc)
Absolute magnitude (M_V)	+0.61^[5]

Details

Mass	2.7^[6] `M`_☉
Radius	3.021 ± 0.038^[7] `R`_☉
Luminosity	63.015 ± 1.307^[7] `L`_☉
Surface gravity (log g)	3.83^[8] cgs
Temperature	9377 ± 75^[7] K
Rotational velocity (v sin i)	46^[9] km/s
Age	500 ± 100^[8] Myr

Other designations
Merak, Mirak,^[10] β Ursae Majoris, β UMa, Beta UMa, 48 Ursae Majoris, BD+57°1302, FK5 416, GC 15145, HD 95418, HIP 53910, HR 4295, PPM 32912, SAO 27876^[11]
Database references
SIMBAD	data