Beta Leonis Minoris

β Leonis Minoris
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Leo Minor
Right ascension	10h 27m 53.000s[1]
Declination	+36° 42′ 25.96″[1]
Apparent magnitude (V)	4.21 (4.40/6.12)[2]
Characteristics
Spectral type	G9III[3]
U−B color index	+0.64[2]
B−V color index	+0.90[2]
R−I color index	+0.46[2]
A
Spectral type	G8III-IV[2]
B
Spectral type	F8IV[2]
Astrometry
Radial velocity (Rv)	8.52[4] km/s
Proper motion (μ)	RA: −127.68[1] mas/yr ; Dec.: −110.31[1] mas/yr
Parallax (π)	21.19 ± 0.50[1] mas
Distance	154 ± 4 ly ; (47 ± 1 pc)
Absolute magnitude (MV)	+0.85[4]
Orbit[5]
Period (P)	14,100 days
Semi-major axis (a)	0.363″
Eccentricity (e)	0.683
Inclination (i)	79.1°
Periastron epoch (T)	MJD 51400
Argument of periastron (ω); (secondary)	215.2°
Semi-amplitude (K1); (primary)	7.97 km/s
Details
A
Mass	2.98±0.10[6] M☉
Radius	9.4±0.3[6] R☉
Luminosity (bolometric)	50.7±1.8[6] L☉
Surface gravity (log g)	2.85[4] cgs
Temperature	5,075[7] K
Metallicity [Fe/H]	+0.09[4] dex
Rotational velocity (v sin i)	2.54[4] km/s
Age	1.2[4] Gyr
B
Mass	1.92±0.04[6] M☉
Radius	3.7±1.5[6] R☉
Luminosity (bolometric)	9.1±4.1[6] L☉
Temperature	6,200[7] K
Other designations
	Beta Leonis Minoris, Beta LMi, β LMi, 31 Leonis Minoris, BD+37 2080, FK5 390, GC 14358, HD 90537, HIP 51233, HR 4100, SAO 62053, PPM 75233, ADS 7780, CCDM J10279+3642, WDS 10279+3642[2][8][9]
Database references
SIMBAD	data

Beta Leonis Minoris (Beta LMi, β Leonis Minoris, β LMi) is a binary star in the constellation of Leo Minor. It has an overall apparent visual magnitude of approximately 4.2. Although it is the only star in Leo Minor with a Bayer designation, it is only the second brightest star in the constellation (the brightest is 46 Leonis Minoris).[7]

Binary system

β Leonis Minoris is a binary that can be resolved for a portion of each orbit. When the two components are too close to resolve, it appears as a single G9 giant star with some indications of a second set of spectral lines. The orbit derived as a double-lined spectroscopic binary is poor, and a better orbit has been calculated using only the spectral lines of the primary, plus input from the known visual observations. The orbital period is nearly 39 years and the eccentricity is high at 0.683. The semi-major axis of the orbit is 0.36″, but the separation varies from 0.1 to 0.6″.[5]

The primary star is a late G-class red clump giant, a star that is fusing helium in its core and lies at the cool end of the horizontal branch.[10] The properties of the secondary star can only be estimated from its relative brightness and its spectral class. It is an F8 subgiant, hotter than the sun and starting to evolve away from the main sequence.[7]

References

Van Leeuwen, F. (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.
HR 4100, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line October 1, 2008.
Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
Deka-Szymankiewicz, B.; Niedzielski, A.; Adamczyk, M.; Adamów, M.; Nowak, G.; Wolszczan, A. (2018). "The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample". Astronomy and Astrophysics. 615: A31. arXiv:1801.02899. Bibcode:2018A&A...615A..31D. doi:10.1051/0004-6361/201731696. S2CID 85526201.
Griffin, R. F. (2008). "Spectroscopic binary orbits from photoelectric radial velocities - Paper 200: Kappa Persei, Beta Leonis Minoris, 56 Ursae Majoris, HR 4593, and 39 Cygni". The Observatory. 128: 176. Bibcode:2008Obs...128..176G.
Wang, Xiaoli; et al. (September 2020). "The Improved Orbit Solution and Component Masses of bet LMi". The Astronomical Journal. 160 (3): 5. Bibcode:2020AJ....160..141W. doi:10.3847/1538-3881/aba7bd. 141.
Beta LMi Archived 2007-08-22 at the Wayback Machine, Stars, Jim Kaler. Accessed on line October 2, 2008.
Entry 10279+3642, The Washington Double Star Catalog Archived 2008-04-13 at the Wayback Machine, United States Naval Observatory. Accessed on line October 1, 2008.
HD 90537 -- Spectroscopic binary, database entry, SIMBAD. Accessed on line October 1, 2008.
Adelman, Saul J. (2001). "On the Photometric Variability of Red Clump Giants". Baltic Astronomy. 10 (4): 593. Bibcode:2001BaltA..10..593A. doi:10.1515/astro-2001-0404.

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[hipparcos-1] Van Leeuwen, F. (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.

[bsc1-2] HR 4100, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line October 1, 2008.

[perkins-3] Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.

[PTPS-4] Deka-Szymankiewicz, B.; Niedzielski, A.; Adamczyk, M.; Adamów, M.; Nowak, G.; Wolszczan, A. (2018). "The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample". Astronomy and Astrophysics. 615: A31. arXiv:1801.02899. Bibcode:2018A&A...615A..31D. doi:10.1051/0004-6361/201731696. S2CID 85526201.

[griffin-5] Griffin, R. F. (2008). "Spectroscopic binary orbits from photoelectric radial velocities - Paper 200: Kappa Persei, Beta Leonis Minoris, 56 Ursae Majoris, HR 4593, and 39 Cygni". The Observatory. 128: 176. Bibcode:2008Obs...128..176G.

[Wang2020-6] Wang, Xiaoli; et al. (September 2020). "The Improved Orbit Solution and Component Masses of bet LMi". The Astronomical Journal. 160 (3): 5. Bibcode:2020AJ....160..141W. doi:10.3847/1538-3881/aba7bd. 141.

[kaler-7] Beta LMi Archived 2007-08-22 at the Wayback Machine, Stars, Jim Kaler. Accessed on line October 2, 2008.

[wds-8] Entry 10279+3642, The Washington Double Star Catalog Archived 2008-04-13 at the Wayback Machine, United States Naval Observatory. Accessed on line October 1, 2008.

[sb0-9] HD 90537 -- Spectroscopic binary, database entry, SIMBAD. Accessed on line October 1, 2008.

[adelman-10] Adelman, Saul J. (2001). "On the Photometric Variability of Red Clump Giants". Baltic Astronomy. 10 (4): 593. Bibcode:2001BaltA..10..593A. doi:10.1515/astro-2001-0404.