IRAS 23304+6147 is a protoplanetary nebula in the constellation Cassiopeia, 16,000 light years away. The central star is a G-type supergiant.[4]

IRAS 23304+6147

The bright red star in the lower left corner of this image is IRAS 23304+6147.
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cassiopeia
Right ascension	23h 32m 44.79s[1]
Declination	+62° 03′ 49.1″[1]
Apparent magnitude (V)	12.99 - 13.15[2]
Characteristics
Spectral type	G2Ia[3]
B−V color index	+2.31 - +2.37[2]
Variable type	Lb[2]
Astrometry
Distance	4,700[3] pc
Details[3]
Luminosity	8,318 L☉
Surface gravity (log g)	0.0 cgs
Temperature	5,900 K
Metallicity [Fe/H]	−0.61 dex
Other designations
2MASS J23324479+6203491
Database references
SIMBAD	data

The nebula is carbon-rich and contains silicon, suggesting that it was formed by a star which was more massive than 4 M_☉. Its spectrum also shows other s-process elements such as barium, yttrium, and lanthanum.[4]

The central star of the protoplanetary nebula has been found to be variable with a small range from visual magnitude +12.99 to +13.15. Although several periods have been identified, these change from year to year and the star has been classified as irregular.[2] The optical variability is dominated by slow pulsation with 83.8 d period, overlapped by faster pulsation modes.[6]

IRAS 23304+6147 is about 15,000 light years away and over eight thousand times as luminous as the sun. It lies in the direction of the Cassiopeia OB7 stellar association, but is thought to be further away.[4]

References