CW Octantis

CW Octantis

A light curve for CW Octantis, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 17h 00m 58.51777s[2]
Declination −86° 21′ 51.4707″[2]
Apparent magnitude (V) 6.03±0.01[3]
Characteristics
Evolutionary stage subgiant[4]
Spectral type A3 IV[5]
U−B color index +0.02[6]
B−V color index +0.05[6]
Variable type α2 CVn[7]
Astrometry
Radial velocity (Rv)7.1±0.5[8] km/s
Proper motion (μ) RA: +8.413 mas/yr[2]
Dec.: −0.032 mas/yr[2]
Parallax (π)5.1828 ± 0.0486 mas[2]
Distance629 ± 6 ly
(193 ± 2 pc)
Absolute magnitude (MV)−0.36[9]
Details
Mass2.98±0.05[4] M☉
Radius4.64[10] R☉
Luminosity111[11] L☉
Surface gravity (log g)3.45±0.07[12] cgs
Temperature8,791[13] K
Metallicity [Fe/H]+0.6[14] dex
Rotation≈2.8 days[13]
Rotational velocity (v sin i)92±6[13] km/s
Age188±4[4] Myr
Other designations
26 G. Octantis[15], CW Octantis, CD−86°100, CPD−86°333, FK5 921, GC 22519, HD 148542, HIP 83255, HR 6139, SAO 258751[16]
Database references
SIMBADdata

CW Octantis, also known as HD 148542, is a solitary, white hued variable star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.03, allowing it to be faintly visible to the naked eye. Parallax measurements from Gaia DR3 place the object at a distance of 629 light years. It appears to be receding from the Solar System with a heliocentric radial velocity of 7.1 km/s.

CW Octantis has a stellar classification of A3 IV, indicating that it is an evolved A-type star heading towards the red giant branch. Zorec and Royer (2012) model it as a dwarf star that has just reached the end of its main sequence lifetime.[4] It has 2.98 times the mass of the Sun[4] and 4.6 times its radius.[10] It radiates 111 times the luminosity of the Sun[11] from its photosphere at an effective temperature of 8,791 K.[13] CW Octantis is estimated to be 188 million years old.[4]

This object is classified as a Alpha2 Canum Venaticorum variable.[7] Most stars of this class have chemical peculiarities in their spectra, but CW Octantis seems to be ordinary. Renson and Manfroid (2009) consider its peculiarity status to be doubtful.[17] Nevertheless, CW Octantis fluctuates between 6.05 and 6.07 in the Hipparcos passband within 2.63 days.[18] It takes 2.8 days to complete a full a rotation, which corresponds to a projected rotational velocity of 92 km/s.[13]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  4. ^ a b c d e f Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference de Vaucouleurs1957 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Samus2003 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Kervella2021 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  13. ^ a b c d e Cite error: The named reference Reiners2004 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Rainer2016 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Renson2009 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Watson2006 was invoked but never defined (see the help page).