Psi Ophiuchi

Psi Ophiuchi
Location of ψ Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 16h 24m 06.18464s[1]
Declination −20° 02′ 14.3784″[1]
Apparent magnitude (V) 4.50[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type K0- II-III[4]
U−B color index +0.84[2]
B−V color index +1.03[2]
Astrometry
Radial velocity (Rv)+0.60[5] km/s
Proper motion (μ) RA: −20.29[1] mas/yr
Dec.: −47.65[1] mas/yr
Parallax (π)16.35 ± 0.25 mas[1]
Distance199 ± 3 ly
(61.2 ± 0.9 pc)
Absolute magnitude (MV)0.806[3]
Details[6]
Mass1.61 M☉
Radius11.45 R☉
Luminosity65.9 L☉
Surface gravity (log g)2.56 cgs
Temperature4,864 K
Metallicity [Fe/H]−0.20 dex
Rotational velocity (v sin i)< 1.0[7] km/s
Other designations
ψ Oph, 4 Ophiuchi, BD−19°4365, FK5 1373, GC 22042, HD 147700, HIP 80343, HR 6104, SAO 159892[8]
Database references
SIMBADdata

Psi Ophiuchi, which is Latinized from ψ Ophiuchi, is a single[9] star in the equatorial constellation of Ophiuchus, next to the western constellation border with Scorpius. It has an orange hue and is visible to the naked eye as a faint point of light with an apparent visual magnitude of 4.50.[2] It is approximately 199 light-years from Earth, based on parallax.[1]

It is an aging giant or bright giant star with a stellar classification of K0- II-III,[4] indicating it has exhausted the supply of hydrogen at its core, then cooled and expanded. It presently has 11 times the girth of the Sun and 1.6 times the Sun's mass.[6] It is a red clump giant, meaning it is on the horizontal branch and is generating energy through core helium fusion.[3] It is radiating 66 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,864 K.[6]

  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 Ducati2002 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Liu2007 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Reffert2015 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference deMedeiros2014 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).