104 Herculis
Star in the constellation Hercules
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104 Herculis is a solitary[11] variable star[2] located around 560[3] light years away from the Sun in the northern constellation of Hercules.[9] It has the variable star designation V669 Herculis and the Bayer designation A Herculis, while 104 Herculis is the Flamsteed designation. This object is visible to the naked eye as a dim, red-hued point of light with a baseline apparent visual magnitude of 4.96.[4] It is moving closer to the Earth with a heliocentric radial velocity of â1.2 km/s.[4]
A visual band light curve for V669 Herculis. The main plot shows the long-term variation (plotted from data published by Tabur et al.[1]) and the inset plot shows the short-term periodic variation (adapted from Adelman and William[2]). | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 11m 54.15649s[3] |
| Declination | +31° 24â² 19.2469â³[3] |
| Apparent magnitude (V) | 4.96[4] |
| Characteristics | |
| Evolutionary stage | AGB[5] |
| Spectral type | M3 III[6] |
| BâV color index | 1.643±0.004[4] |
| Variable type | semiregular[7] |
| Astrometry | |
| Radial velocity (Rv) | â1.19±0.29[4] km/s |
| Proper motion (μ) | RA: â15.172[3] mas/yr Dec.: +25.084[3] mas/yr |
| Parallax (Ï) | 5.8167±0.1769 mas[3] |
| Distance | 560 ± 20 ly (172 ± 5 pc) |
| Absolute magnitude (MV) | â1.15[4] |
| Details | |
| Radius | 85.80+6.65 â10.88[3] Râ |
| Luminosity | 1,202.3±42.1[3] Lâ |
| Surface gravity (log g) | 0.99±0.29[8] cgs |
| Temperature | 3,535±24[8] K |
| Metallicity [Fe/H] | â0.08±0.10[8] dex |
| Other designations | |
| A Her, 104 Her, V669 Her, AAVSO 1808+31B, BD+31°3199, FK5 3448, HD 167006, HIP 89172, HR 6815, SAO 66737[9][10] | |
| Database references | |
| SIMBAD | data |
The variability of the brightness of 104 Herculis was announced by Joel Stebbins and Charles Morse Huffer in 1928, based on observations made at Washburn Observatory.[12] It was given its variable star designation in 1977.[13]
This is an aging red giant star on the asymptotic giant branch[5] with a stellar classification of M3 III.[6] It is a semiregular variable[7] with an amplitude of 0.14 in the B-band[14] and pulsation periods of 22.9 and 24.0 days.[1] Having exhausted the hydrogen at its core, the star has expanded to 86 times the Sun's radius.[3] It is radiating 1,202 times the Sun's luminosity[3] from its swollen photosphere at an effective temperature of 3,535 K.[8]