HD 173780

HD 173780
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 18h 46m 04.47950s[1]
Declination +26° 39′ 43.6644″[1]
Apparent magnitude (V) +4.84[2]
Characteristics
Evolutionary stage Horizontal-branch[3]
Spectral type K3III[4]
B−V color index 1.20[2]
Astrometry
Radial velocity (Rv)−16.92±0.17[1] km/s
Proper motion (μ) RA: +17.460[1] mas/yr
Dec.: +23.819[1] mas/yr
Parallax (π)13.7599 ± 0.1315 mas[1]
Distance237 ± 2 ly
(72.7 ± 0.7 pc)
Absolute magnitude (MV)0.37[5]
Details
Mass1.70[2] M☉
Radius16.38+0.22
−0.47[1] R☉
Luminosity91.5±1.0[1] L☉
Surface gravity (log g)2.42±0.08[6] cgs
Temperature4,468±19[6] K
Metallicity [Fe/H]−0.04±0.05[6] dex
Rotational velocity (v sin i)3.8[7] km/s
Age2.42[2] Gyr
Other designations
BD+26°3349, HD 173780, HIP 92088, HR 7064, SAO 86418[8]
Database references
SIMBADdata

HD 173780 is a single[9] star in the northern constellation Lyra, near the southern constellation border with Hercules. It is an orange-hued star that is faintly visible to the naked eye with an apparent visual magnitude of +4.84.[2] This object is located at a distance of approximately 237 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −17 km/s.[1]

This is an aging giant star with a stellar classification of K3III.[4] 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 2.4 billion years old with 1.7 times the mass of the Sun.[2] With the supply of hydrogen exhausted at its core, it has expanded to 16 times the radius of the Sun. The star is radiating 92 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,468 K.[1]

  1. ^ a b c d e f g h i j 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 Luck2015 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. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Wu2011 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Massarotti2008 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).