9 Cassiopeiae

Location of 9 Cassiopeiae (circled)
Observation data Epoch J2000.0       Equinox J2000.0
Constellation	Cassiopeia
Right ascension	00h 04m 13.6625s [1]
Declination	+62° 17′ 15.591″ [1]
Apparent magnitude (V)	+5.884 [2]
Characteristics
Spectral type	A1II-III [3]
U−B color index	+0.29 [4]
B−V color index	+0.30 [4]
Astrometry
Radial velocity (Rv)	−23.43±0.16 [1] km/s
Proper motion (μ)	RA: −0.936 [1]  mas/ yr Dec.: −0.263 [1]  mas/ yr
Parallax (π)	1.3781 ± 0.0237  mas [1]
Distance	2,370 ± 40  ly (730 ± 10  pc)
Details
Mass	5.1 [5]  M☉
Radius	26 [6]  R☉
Luminosity	2,208 [6]  L☉
Surface gravity (log g)	2.08 [5]  cgs
Temperature	7,719 [6]  K
Metallicity [Fe/H]	−0.32 [5]  dex
Rotational velocity (v sin i)	33 [7] km/s
Age	25.1 [8]  Myr
Other designations
9 Cas, HR 9100, HD 225180, BD+61°2586, HIP 330
Database references
SIMBAD	data

9 Cassiopeiae (9 Cas) is a white giant star in the constellation Cassiopeia, about 2,370 light years away.

9 Cassiopeiae is classified as an A1 type giant or bright giant. One study noted peculiarities in the spectrum that could indicate a λ Boötis star, ^[9] but other researchers have refuted this. ^{[10] [7]}

At an age of 25 million years, 9 Cassiopeiae has expanded away from the main sequence after exhausting its core hydrogen and now has a radius about 26 times that of the Sun. With an effective temperature of about 7,700  K, it emits more than two thousand times the luminosity of the Sun.

9 Cassiopeiae has a number of faint companions listed in multiple star catalogues, ^[11] but they all appear to be at different distances ^[12] and none are thought to be gravitationally associated. ^[13]