98 Herculis is a single[7] 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.[8] The star is moving closer to the Earth with a heliocentric radial velocity of −19 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 |
| Spectral type | M3-SIII[3] or M3IIIBa0.2[4] |
| B−V color index | 1.656±0.062[2] |
| Variable type | suspected[5] |
| 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 | |
| Radius | 85.39+10.72 −8.50[1] R☉ |
| Luminosity | 1,329.7±44.7[1] L☉ |
| Temperature | 3,772+203 −217[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an aging red giant star on the asymptotic giant branch[9] with a stellar classification of M3-SIII,[3] where the suffix notation indicating this is an S-type star. It is a mild barium star with an intensity class of 0.2,[10][4] and is a suspected variable star, although Percy and Shepherd (1992) were unable to confirm this.[11] 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]
References
edit- ^ a b c d e f g h i j k l Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ^ a b Lu, Phillip K. (1991), "Taxonomy of barium stars", Astronomical Journal, 101: 2229, Bibcode:1991AJ....101.2229L, doi:10.1086/115845.
- ^ Samus, N. N.; Durlevich, O. V.; et al. (2009), "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)", VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S, 1: B/gcvs, Bibcode:2009yCat....102025S.
- ^ "98 Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-17.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304.
- ^ Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal, 104 (1): 275–313, Bibcode:1992AJ....104..275E, doi:10.1086/116239.
- ^ Gomez, A. E.; et al. (1997), "Absolute magnitudes and kinematics of barium stars", Astronomy and Astrophysics, 319: 881, Bibcode:1997A&A...319..881G.
- ^ Percy, J. R.; Shepherd, C. W. (October 1992), "A Photometric Survey of Small-Amplitude Red Variables", Information Bulletin on Variable Stars, 3792: 1, Bibcode:1992IBVS.3792....1P.