30 Piscium

30 Piscium
Location of 30 (also called YY) Piscium (circled). It presents in a narrow triangle with two other stars of similar brightness, 27 and 33 Piscium.
Observation data
Epoch J2000      Equinox J2000
Constellation Pisces
Right ascension 00h 01m 57.61947s[1]
Declination −06° 00′ 50.6540″[1]
Apparent magnitude (V) 4.31 – 4.41[2]
Characteristics
Spectral type M3 III[3]
B−V color index 1.631±0.011[4]
Variable type LPV,[5] LB?[2]
Astrometry
Radial velocity (Rv)−11.7±0.5[6] km/s
Proper motion (μ) RA: 46.941 mas/yr[1]
Dec.: −40.471 mas/yr[1]
Parallax (π)7.8758 ± 0.4105 mas[1]
Distance410 ± 20 ly
(127 ± 7 pc)
Absolute magnitude (MV)−1.20[5]
Details
Radius109.2+5.46
−6.05[7] R☉
Luminosity1,597±177[7] L☉
Surface gravity (log g)2[8] cgs
Temperature3,490±35[7] K
Other designations
30 Psc, YY Psc, BD−06° 6345, FK5 1630, HD 224935, HIP 154, HR 9089, SAO 147042[9]
Database references
SIMBADdata

30 Piscium (HIP 154) is a solitary[10] variable star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.37.[8] Its calculated mid-value of antiposed parallax shift as the Earth moves around the Sun of very roughly 7.88 mas, makes it around 410 light years away.[1] Its net movement in the present epoch is one of moving closer – radial velocity (speed away from our star system) is −12 km/s.[6]

A visual band light curve for YY Piscium, plotted from data published by Tabur et al. (2009)[11]

This is an aging red giant star with a stellar classification of M3 III,[3] indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a candidate long-period variable star[5] and has been given the designation YY Psc.[12] 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.[11] The star has 109 times the Sun's radius and is radiating 1,600 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,490 K.[7]

  1. ^ a b c d e Cite error: The named reference DR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Rimoldini2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference baines was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Martinez2014 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference tabur was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kukarkin1975 was invoked but never defined (see the help page).