49 Aquarii

49 Aquarii
Observation data; Epoch J2000 Equinox J2000
Constellation	Aquarius
Right ascension	22h 23m 30.84904s
Declination	−24° 45′ 45.5865″
Apparent magnitude (V)	5.53
Characteristics
Spectral type	K0 III CN II
B−V color index	0.979±0.003
Astrometry
Radial velocity (Rv)	−12.97±0.07 km/s
Proper motion (μ)	RA: +98.380 mas/yr ; Dec.: −2.909 mas/yr
Parallax (π)	12.2800 ± 0.0965 mas
Distance	266 ± 2 ly ; (81.4 ± 0.6 pc)
Absolute magnitude (MV)	1.01
Details
Mass	2.18±0.14 M☉
Radius	9.10±0.51 R☉
Luminosity	50.1+11.6; −9.4 L☉
Surface gravity (log g)	2.85±0.09 cgs
Temperature	4,954±24 K
Metallicity [Fe/H]	+0.05±0.03 dex
Rotational velocity (v sin i)	1.42±0.45 km/s
Age	950±210 Myr
Other designations
	CD−25° 15905, HD 212271, HIP 110529, HR 8529, SAO 191105
Database references
SIMBAD	data

49 Aquarii, abbreviated 49 Aqr, is a star in the zodiac constellation of Aquarius. 49 Aquarii is its Flamsteed designation. It is a dim star with an apparent visual magnitude of 5.53.^[2] The distance to 49 Aqr, as determined from its annual parallax shift of 12.28 mas,^[1] is 266 light years. It is moving closer to the Earth with a heliocentric radial velocity of −13 km/s.^[4]

This is an aging K-type giant star with a stellar classification of K0 III CN II.^[3] It shows a spectral anomaly with the absorption lines of cyanogen (CN). This is a red clump giant, indicating that it is generating energy through the helium fusion at its core.^[6] It is around 950 million years old with 2.2 times the mass of the Sun and has expanded to nine times the Sun's radius. It is radiating 50 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,954 K.^[4]

References

^ ^a ^b ^c ^d ^e ^f 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.
^ ^a ^b ^c ^d 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.
^ ^a ^b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
^ ^a ^b ^c ^d Jofré, E.; et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: A50, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474, S2CID 53666931.
^ "49 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 23, 2018.
^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.