G Herculis

G Herculis

A light curve for g Herculis, plotted from Hipparcos data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 16h 28m 38.54859s[2]
Declination +41° 52′ 54.0406″[2]
Apparent magnitude (V) 4.3 - 6.3[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M6− III[5]
B−V color index 1.289±0.024[6]
Variable type SRb[3]
Astrometry
Radial velocity (Rv)1.49±0.38[6] km/s
Proper motion (μ) RA: +30.16[2] mas/yr
Dec.: −5.14[2] mas/yr
Parallax (π)9.21 ± 0.18 mas[2]
Distance354 ± 7 ly
(109 ± 2 pc)
Absolute magnitude (MV)−0.41[7]
Orbit[4]
Period (P)843.7±21.1 d
Eccentricity (e)0.37±0.11
Periastron epoch (T)2,451,918.2±43.9 HJD
Argument of periastron (ω)
(secondary)		246±21°
Semi-amplitude (K1)
(primary)		2.3±0.3 km/s
Details
g Her A
Mass1.65±0.30[8] M☉
Radius230[9] R☉
Luminosity5,395[9] L☉
Surface gravity (log g)0.20[10] cgs
Temperature3,263±23[9] K
Metallicity [Fe/H]−0.01[10] dex
Other designations
g Her, 30 Her, BD+42°2714, FK5 3303, HD 148783, HIP 80704, HR 6146, SAO 46108[11]
Database references
SIMBADdata

g Herculis is a binary star[12] system in the northern constellation of Hercules. It has the Flamsteed designation 30 Herculis, while g Herculis is the Bayer designation. This system is visible to the naked eye as a faint, red-hued point of light. Based upon a measured parallax of 9.2 mas, it is located around 354 light years away from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of 1.5 km/s.[6]

This is a single-lined spectroscopic binary with an orbital period of 2.310 years and an eccentricity of 0.37.[4] The visible component is an aging red giant on the asymptotic giant branch[4] with a stellar classification of M6− III.[5] According to Samus et al. (2017), it is a semiregular variable of subtype SRb, which ranges between visual magnitudes 4.3 and 6.3 over 89.2 days.[3][13] It displays cyclical periods of 62.3, 89.5, and 888.9 days.[4] The star is surrounded by a circumstellar dust shell that seems primarily composed of oxides of iron, magnesium, and aluminium, rather than silicates.[14]

  1. ^ Cite error: The named reference HIPCurve was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference Hinkle2002 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Schiavon2007 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Halabi2015 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Ayres2023 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Ramírez2000 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference AAVSO30 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Posch2002 was invoked but never defined (see the help page).