98 Herculis
Aging red giant star in the constellation Hercules
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98 Herculis is a single[9] star located approximately 590[1] light years from the Sun in the northern constellation Hercules. It is visible to the naked eye as a dim, red-hued point of light with an apparent visual magnitude of 4.96.[2] The brightness of the star is diminished by an extinction of 0.19 due to interstellar dust.[10] The star is moving closer to the Earth with a heliocentric radial velocity of −19 km/s.[2]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 06m 01.90000s[1] |
| Declination | +22° 13′ 07.9396″[1] |
| Apparent magnitude (V) | 4.96[2] |
| Characteristics | |
| Evolutionary stage | AGB[3] |
| Spectral type | M3-SIII[4] or M3IIIBa0.2[5] |
| B−V color index | 1.656±0.062[2] |
| Variable type | suspected[6] |
| Astrometry | |
| Radial velocity (Rv) | −19.48±0.21[2] km/s |
| Proper motion (μ) | RA: −12.028[1] mas/yr Dec.: −6.067[1] mas/yr |
| Parallax (π) | 5.5201±0.1610 mas[1] |
| Distance | 590 ± 20 ly (181 ± 5 pc) |
| Absolute magnitude (MV) | −1.78[2] |
| Details | |
| Mass | 1.35[7] M☉ |
| Radius | 85.39+10.72 −8.50[1] R☉ |
| Luminosity | 1,329.7±44.7[1] L☉ |
| Surface gravity (log g) | 1.45[7] cgs |
| Temperature | 3,772+203 −217[1] K |
| Metallicity [Fe/H] | −0.08[7] dex |
| Other designations | |
| 98 Her, NSV 10208, BD+22°3273, HD 165625, HIP 88657, HR 6765, SAO 85725[8] | |
| Database references | |
| SIMBAD | data |
This is an aging red giant star on the asymptotic giant branch[3] with a stellar classification of M3-SIII,[4] where the suffix notation indicating this is an S-type star. It is a mild barium star with an intensity class of 0.2,[11][5] and is a suspected variable star, although Percy and Shepherd (1992) were unable to confirm this.[12] With the hydrogen at its core exhausted, the star has expanded to around 85[1] times the Sun's radius. It is radiating 1,330[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,772 K.[1]