Historical view of the Hercules constellation showing Rukbalgethi Genubi (θ Her) as the "southern knee", right of center
Observation data Epoch J2000 Equinox J2000
Constellation
Hercules
Right ascension
17h 56m 15.18054s[1]
Declination
37° 15′ 01.9343″[1]
Apparent magnitude (V)
3.851[2]
Characteristics
Spectral type
K1IIaCN2[3]
U−B color index
+1.40 [4]
B−V color index
+1.35[4]
R−I color index
+0.63[5]
Variable type
Irregular (suspected)[6]
Astrometry
Radial velocity (Rv)
–28.32[7] km/s
Proper motion (μ)
RA: 2.67[1] mas/yr Dec.: 6.47[1] mas/yr
Parallax (π)
4.33 ± 0.13 mas[1]
Distance
750 ± 20 ly (231 ± 7 pc)
Absolute magnitude (MV)
−2.71+0.26 −0.23[8]
Details
Mass
4.94[9]M☉
Radius
89.97[9]R☉
Luminosity
2,405.7[9]L☉
Surface gravity (log g)
1.24[9] cgs
Temperature
4,266[9] K
Metallicity [Fe/H]
−0.11[9] dex
Rotational velocity (v sin i)
3.4 ± 0.6[8] km/s
Age
130[9] Myr
Other designations
Rukbalgethi Genubi, θ Her, 91 Her, BD+37°2982, FK5 672, GC 24415, HD 163770, HIP 87808, HR 6695, SAO 66485[10]
Database references
SIMBAD
data
Theta Herculis is a single,[11] variable star in the northern constellation of Hercules. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 3.851.[2] Based upon parallax measurements, it is located around 750 light years away from the Sun. The star is advancing toward the Earth with a heliocentric radial velocity of –28 km/s.[7]
This is an aging K-type bright giant with a stellar classification of K1IIaCN2,[3] where the suffix notation indicates a strong overabundance of CN in the spectrum. The brightness variations of this star was first noticed in 1935 by M. Fedtke and confirmed by Erich Przybyllok and Kurt Walter the same year.[12] French astronomer Paul Muller then classified Theta Herculis as an irregular variable with a range of magnitudes between 3.7 and 4.1 and a periodicity of roughly 8–9 days.[6]
The star is about 130[9] million years old with 4.94[9] times the mass of the Sun. With the hydrogen at its core exhausted, the star has expanded to 90[9] times the Sun's radius. It is radiating 2,406[9] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,266 K.[9]
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^"tet Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-05-31.
^Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
^Cite error: The named reference Shapiro1972 was invoked but never defined (see the help page).
ThetaHerculis is a single, variable star in the northern constellation of Hercules. This object is visible to the naked eye as a faint, orange-hued star...
states in China, consisting of Theta Serpentis, Delta Herculis, Lambda Herculis, Mu Herculis, Omicron Herculis, 112 Herculis, Zeta Aquilae, Eta Serpentis...
border from Auriga into the constellation Lynx Also designated Psi Herculis (ψ Herculis, ψ Her) by Bayer, after Ptolemy – Bayer’s Uranometria and Bayer letters...
Star Maximum brightness 2.76 Theta Carinae Binary star system 2.765 Gamma Lupi Triple star system 2.77 2.76 Beta Herculis Binary star system 2.77 2.76...
Theta Aurigae (Latinized from θ Aurigae, abbreviated Theta Aur, θ Aur) is a binary star in the constellation of Auriga. Based upon parallax measurements...
earth, is traveling in the direction of Ophiuchus. It is located between α Herculis, α Ophiuchi and κ Ophiuchi at right ascension 17h 13m and declination +12°...
Khosroshahi, Habib; Wasatonic, Rick (2013). "THE AGE AND MASS OF THE α HERCULIS TRIPLE-STAR SYSTEM FROM a MESA GRID OF ROTATING STARS WITH 1.3 ⩽ M / M...
Athletics. A month after that, she took her best down to 50.29 at the Herculis meet in Monaco. She took it down one more time to 50.24 in the semi-finals...
However, it is more likely derived from Alrucaba or Rucaba, a name applied to Theta Ursae Majoris.: 58 In 2016, the International Astronomical Union organized...
varies between magnitudes 6.99 and 7.83 over 159 days. VY Pyxidis is a BL Herculis variable (type II Cepheid), ranging between apparent magnitudes 7.13 and...
River's or Stream's End / Tail / Edge / Border آخر النهر آخِرُ ٱلْنََهْر Theta Eridani Achernar Ākhiru-n-Nahr the River's or Stream's End / Tail / Edge...
of Left Wall Lambda Herculis Maasym 趙 Zhào The state of Zhao 天市左垣三 Tiān Shì Zuǒ Yuán sān the Third Star of Left Wall Mu Herculis 九河 Jiǔ Hé Jiuhe 天市左垣四...
Hertzsprung SONG Telescope: Asteroseismology of the G5 Subgiant Star μ Herculis". The Astrophysical Journal. 836 (1): 142. arXiv:1701.03365. Bibcode:2017ApJ...
enclosure, consisting of Zeta Aquilae; Delta, Lambda, Mu, Omicron and 112 Herculis; Theta¹ and Eta Serpentis; Nu Ophiuchi, Xi Serpentis and Eta Ophiuchi. Consequently...
Martell, P. (2010-05-07). "Spectral Mapping of the Intermediate Polar Dq Herculis". The Astronomical Journal. 139 (6): 2542–2556. arXiv:1005.1612. Bibcode:2010AJ...
elemental abundance analyses of B and A stars. V. The normal stars theta Leonis, tau Herculis, 14 Cygni and 5 Aquarii", Astronomy and Astrophysics Supplement...