Iota Sagittarii

ι Sagittarii
Location of ι Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 19h 55m 15.69691s[1]
Declination −41° 52′ 05.8388″[1]
Apparent magnitude (V) +4.118[2]
Characteristics
Spectral type K0 II-III[3]
U−B color index +0.911[2]
B−V color index +1.084[2]
Astrometry
Radial velocity (Rv)+35.8[3] km/s
Proper motion (μ) RA: +22.61[1] mas/yr
Dec.: +51.40[1] mas/yr
Parallax (π)17.94 ± 0.21 mas[1]
Distance182 ± 2 ly
(55.7 ± 0.7 pc)
Absolute magnitude (MV)+0.39[4]
Details
Mass1.40[3] M☉
Radius14[5] R☉
Luminosity87[3] L☉
Surface gravity (log g)1.89[6] cgs
Temperature4,594±41[3] K
Metallicity [Fe/H]−0.26[6] dex
Age4.74[3] Gyr
Other designations
ι Sgr, CPD−42° 8944, FK5 1520, HD 188114, HIP 98032, HR 7581, SAO 229927[7]
Database references
SIMBADdata

Iota Sagittarii (Iota Sgr, ι Sagittarii, ι Sgr) is a star in the zodiac constellation of Sagittarius. With an apparent visual magnitude of +4.118, it is bright enough to be viewed with the naked eye.[2] Based upon an annual parallax shift of 17.94 mas as seen from Earth,[1] this star is located 182 light years from the Sun. It is moving away from the Earth with a radial velocity of +35.8 km/s.[3]

This is a probable astrometric binary,[8] based upon proper motion data collected during the Hipparcos mission.[9] The visible component shows the spectrum of an evolved K-type giant or bright giant star with a stellar classification of K0 II-III.[3] The measured angular diameter, after correction for limb darkening, is 2.32±0.02 mas.[10] At an estimated distance of this star, this yields a physical size of about 14 times the radius of the Sun.[5] It has 1.4[3] times the mass of the Sun and is radiating 87[3] times the Sun's luminosity from its photosphere at an effective temperature of about 4,594 K.[3]

  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 Cousins1973 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i j k Cite error: The named reference luck2015 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 Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Soubiran2010 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Frankowski2007 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Richichi2005 was invoked but never defined (see the help page).