9 Lacertae

9 Lacertae is a single^[9] star in the northern constellation Lacerta, located 172 light years away from Sun.^[1] It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.64.^[2] This object is moving further from the Earth with a heliocentric radial velocity of +10 km/s.^[2]

9 Lacertae

Observation data Epoch J2000      Equinox J2000
Constellation	Lacerta
Right ascension	22h 37m 22.41727s[1]
Declination	+51° 32′ 42.4383″[1]
Apparent magnitude (V)	4.64[2]
Characteristics
Evolutionary stage	main sequence
Spectral type	A9VkA7mA6[3]
B−V color index	0.254±0.006[2]
Astrometry
Radial velocity (Rv)	+10.1±1.5[2] km/s
Proper motion (μ)	RA: −51.83[1] mas/yr Dec.: −103.80[1] mas/yr
Parallax (π)	19.00 ± 0.19 mas[1]
Distance	172 ± 2 ly (52.6 ± 0.5 pc)
Absolute magnitude (MV)	1.03[2]
Details
Mass	1.59[4] M☉
Radius	2.1[5] R☉
Luminosity	34.6+0.9 −1.0[6] L☉
Surface gravity (log g)	3.77±0.14[4] cgs
Temperature	7,614±259[4] K
Metallicity [Fe/H]	−0.20[7] dex
Rotational velocity (v sin i)	105[6] km/s
Age	513[4] Myr
Other designations
9 Lac, BD+50° 3770, HD 214454, HIP 111674, HR 8613, SAO 34628[8]
Database references
SIMBAD	data

This is an A-type main-sequence star with a stellar classification of A9VkA7mA6.^[3] This notation indicates it has the Hydrogen lines of an A9 star, the Calcium K line of an A7 star, and the metal lines of an A6. It is 513^[4] million years old with a high projected rotational velocity of 105 km/s.^[6] The star has 1.59^[4] times the mass of the Sun and about 2.1^[5] times the Sun's radius. It is radiating 34.6^[6] times the Sun's luminosity from its photosphere at an effective temperature of 7,614 K.^[4]

References

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.
2. 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.
3. Gray, R. O.; et al. (2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
4. 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, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
5. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
6. Zorec, J.; et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
7. Erspamer, D.; North, P. (February 2003), "Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE", Astronomy and Astrophysics, 398 (3): 1121–1135, arXiv:astro-ph/0210065, Bibcode:2003A&A...398.1121E, doi:10.1051/0004-6361:20021711, S2CID 1109164.
8. "9 Lac". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-31.
9. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.