30 Piscium
30 Piscium (HIP 154) is a solitary variable star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.37. Its calculated mid-value of antiposed parallax shift as the Earth moves around the Sun of very roughly 7.8859 mas, makes it around 410 light years away. Its net movement in the present epoch is one of moving closer – radial velocity (speed away from our star system) is −12 km/s.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pisces |
| Right ascension | 00h 01m 57.61523s |
| Declination | −06° 00′ 50.6684″ |
| Apparent magnitude (V) | 4.31 – 4.41 |
| Characteristics | |
| Spectral type | M3 III |
| B−V color index | 1.631±0.011 |
| Variable type | LPV, LB? |
| Astrometry | |
| Radial velocity (Rv) | −11.7±0.5 km/s |
| Proper motion (μ) | RA: +51.158 mas/yr Dec.: −39.551 mas/yr |
| Parallax (π) | 7.8859 ± 0.4358 mas |
| Distance | 410 ± 20 ly (127 ± 7 pc) |
| Absolute magnitude (MV) | −1.20 |
| Details | |
| Radius | 73.66+16.69 −6.79 R☉ |
| Luminosity | 1,148.5±71.1 L☉ |
| Surface gravity (log g) | 2 cgs |
| Temperature | 3,647 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an aging red giant star with a stellar classification of M3 III, indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a candidate long-period variable star and has been given the designation YY Psc. It varies in brightness between magnitudes 4.31 and 4.41 with no clear period. Possible periods of 23.1, 32.0, 53.6, and 167.8 days have been identified. The star has 74 times the Sun's radius and is radiating 1,148.5 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,647 K.