9 Cassiopeiae

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

9 Cassiopeiae

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

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,^[10] but other researchers have refuted this.^[11][8]

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,^[12] but they all appear to be at different distances^[13] and none are thought to be gravitationally associated.^[14]