HD 180450

HD 180450 is a single^[4] star in the northern constellation of Lyra, positioned about half a degree to the NNW of the globular cluster M56.^[5] At an apparent visual magnitude of 5.88,^[2] it is dimly visible to the naked eye under good viewing conditions. This star is located at a distance of approximately 1,400 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −64.4 km/s.^[1]

HD 180450

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Lyra
Right ascension	19h 15m 24.85937s[1]
Declination	+30° 31′ 34.9760″[1]
Apparent magnitude (V)	5.88[2]
Characteristics
Spectral type	M1IIIab[2]
U−B color index	+2.03
B−V color index	+1.665±0.007[2]
Astrometry
Radial velocity (Rv)	−64.43±0.23[1] km/s
Proper motion (μ)	RA: 34.425[1] mas/yr Dec.: −26.081[1] mas/yr
Parallax (π)	2.37 ± 0.61 mas[1]
Distance	approx. 1,400 ly (approx. 400 pc)
Absolute magnitude (MV)	−2.03[2]
Details
Radius	68+12 −13[1] R☉
Luminosity	1,002±34[1] L☉
Temperature	3,947+433 −305[1] K
Other designations
BD+30°3491, GC 26550, HD 180450, HIP 94630, HR 7302, SAO 68040, GSC 02653-01682[3]
Database references
SIMBAD	data

This is an aging red giant star with a stellar classification of M1IIIab,^[2] It is currently on the asymptotic giant branch,^[6] having exhausted the supply of hydrogen in its core and evolved of the main sequence. It has expanded to ~68 times the radius of the Sun and is radiating a thousand times the Sun' luminosity from its enlarged photosphere at en effective temperature of 3,947 K.^[1]

References

1. 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. Gaia DR2 record for this source at VizieR.
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. "HD 180450". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-14.
4. Eggleton, P. P.; Tokovinin, A. A. (September 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.
5. Sinnott, Roger W.; Perryman, Michael A. C. (1997), Millennium Star Atlas, vol. 3, Sky Publishing Corporation and the European Space Agency, p. 1174, ISBN 0-933346-84-0.
6. Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal, 104 (1): 275–313, Bibcode:1992AJ....104..275E, doi:10.1086/116239.