60 Sagittarii

60 Sagittarii

The four stars of the Terebellum
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 19h 58m 57.20292s[1]
Declination −26° 11′ 44.7585″[1]
Apparent magnitude (V) 4.84[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type G6 III[4]
U−B color index +0.55[5]
B−V color index +0.882±0.038[2]
R−I color index +0.47[5]
Astrometry
Radial velocity (Rv)−51.1±2.4[2] km/s
Proper motion (μ) RA: +35.31[6] mas/yr
Dec.: +25.69[6] mas/yr
Parallax (π)8.6025 ± 0.1732 mas[1]
Distance379 ± 8 ly
(116 ± 2 pc)
Absolute magnitude (MV)−0.07[2]
Details
Radius17.42+0.68
−0.80[1] R☉
Luminosity170.3±4.0[1] L☉
Surface gravity (log g)2.78[7] cgs
Temperature4,997+119
−96[1] K
Metallicity [Fe/H]−0.38[7] dex
Other designations
A Sgr[8], 60 Sgr, CD−26°14682, CPD−26°6895, GC 27658, HD 189005, HIP 98353, HR 7618, SAO 188778, PPM 270516[9]
Database references
SIMBADdata

60 Sagittarii is a suspected binary star[10] system in the southern constellation of Sagittarius. It has the Bayer designation A Sagittarii, while 60 Sagittarii is the Flamsteed designation. This naked-eye object forms the northwest corner of the asterism called the Terebellum and, with an apparent magnitude of approximately 4.84,[2] it is the dimmest of the four stars in the Terebellum. It is located 379 light-years from the Sun, based on parallax, but is moving closer with a radial velocity of −51 km/s.[2]

The visible component is an aging G-type giant star with a stellar classification of G6 III,[4] having exhausted the supply of hydrogen at its core and expanded to 17[1] the Sun's radius. In the Bright Star Catalogue it was listed with a class of G6 III Ba0.2,[5] suggesting it is a mild barium star and thus might have a white dwarf companion.[10] It is a red clump giant, indicating it is on the horizontal branch and is generating energy through the fusion of helium at its core.[3] The star is radiating 170[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,997 K.[1]

  1. ^ a b c d e f g h i Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Alves2000 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference perkins1989 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference bsc1 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Alves2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference xref 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. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).