Upsilon1 Cassiopeiae

For other star systems with this Bayer designation, see υ Cassiopeiae.
υ1 Cassiopeiae
Location of υ1 Cassiopeiae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cassiopeia
Right ascension 00h 55m 00.15523s[1]
Declination +58° 58′ 21.7108″[1]
Apparent magnitude (V) 4.82[2]
Characteristics
Spectral type K2 III[3]
U−B color index +1.25[2]
B−V color index +1.21[2]
Astrometry
Radial velocity (Rv)−23.57[4] km/s
Proper motion (μ) RA: −33.50±0.36[1] mas/yr
Dec.: −40.82±0.33[1] mas/yr
Parallax (π)9.93 ± 0.49 mas[1]
Distance330 ± 20 ly
(101 ± 5 pc)
Absolute magnitude (MV)−0.644[4]
Details
Mass1.39[5] M☉
Radius21[6] R☉
Luminosity174[5] L☉
Surface gravity (log g)1.76[4] cgs
Temperature4,422±14[5] K
Metallicity [Fe/H]−0.25[4] dex
Rotational velocity (v sin i)1.1[7] km/s
Age4.75[5] Gyr
Other designations
υ1 Cas, 26 Cas, BD+58° 134, HD 5234, HIP 4292, HR 253, SAO 21832, ADS 748, CCDM J00551+5858, WDS J00550+5858A[8]
Database references
SIMBADdata
υ1 Cassiopeiae is the bright star in the lower right. The bright star in the upper left is υ2 Cassiopeiae.

Upsilon1 Cassiopeiae (υ1 Cassiopeiae) is an astrometric binary[9] star system in the northern constellation of Cassiopeia. It is visible to the naked eye with an apparent visual magnitude of 4.82.[2] Based upon an annual parallax shift of 9.93 mas as seen from Earth,[1] this system is located about 330 light years from the Sun.

The visible component is an evolved K-type giant star with a stellar classification of K2 III.[3] With an estimated age of 4.75 billion years,[5] it is a red clump star that is generating energy through the fusion of helium at its core.[10] The measured angular diameter, after correction for limb darkening, is 1.97±0.02 mas.[11] At the estimated distance of the star, this yields a physical size of about 21 times the radius of the Sun.[6] It has 1.39 times the mass of the Sun and is radiating 174 times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,422 K.[5]

There is a magnitude 12.50 visual companion at an angular separation of 17.80 arc seconds along a position angle of 61°, as of 2003. A more distant magnitude 12.89 companion lies at a separation of 93.30 arc seconds along a position angle of 125°, as measured in 2003. Neither star appears to be physically associated with υ1 Cas.[12]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Argue1966 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference rob51 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Soubiran2008 was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference Luck2015 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference DeMedeiros2000 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Valentini2010 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Richichi2005 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Mason2014 was invoked but never defined (see the help page).