Red giant star in the constellation Hercules
42 Herculis 42 Herculis in optical light
Observation dataEpoch J2000 Equinox J2000 Constellation Hercules Right ascension 16h 38m 44.84465s [ 1] Declination +48° 55′ 42.0160″[ 1] Apparent magnitude (V)4.86[ 2] Characteristics Evolutionary stage asymptotic giant branch[ 3] Spectral type M2.5III[ 3] B−Vcolor index ± 0.011[ 2] Astrometry Radial velocity (Rv )± 0.33[ 2] km/s Proper motion (μ)RA: −47.768[ 1] mas /yr Dec.: +27.349[ 1] mas /yr Parallax (π)7.2737± 0.1764 mas [ 1] Distance 450 ± 10 ly pc ) Absolute magnitude (MV )−0.65[ 2] Details Mass 1.10[ 4] M ☉ Radius 61[ 5] R ☉ Luminosity 682[ 5] L ☉ Surface gravity (log g )1.77[ 4] cgs Temperature 3,878[ 4] K Metallicity [Fe/H] −0.09[ 4] dex Other designations 42 Her ,NSV 7896AAVSO 1636+49BD +49°2531FK5 1434HD 150450HIP 81497HR 6200SAO 46210WDS J16387+4856[ 6] Database references SIMBAD data
42 Herculis is a single[ 7] star located around 450[ 1] light years away from the Sun in the northernconstellation ofHercules .[ 6] apparent visual magnitude of 4.86.[ 2] radial velocity of −56 km/s.[ 2]
This is an agingred giant star on theasymptotic giant branch with astellar classification of M2.5III.[ 3] variable star ,[ 6] photometric survey found the brightness to be constant.[ 8] core , the star has expanded to 61 times theSun's radius . It is radiating 682 times theluminosity of the Sun from its swollenphotosphere at aneffective temperature ofK
There is an unknown source ofX-ray andfar ultraviolet emission originating from a location offset by more than one arcsecond from the star.[ 9] main sequence companion.[ 10]
^a b c d e f 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 atVizieR .^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 c 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 . ^a b c d Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G.; Valentini, M.; Torralba Elipe, G.; Steinmetz, M.; Pantaleoni-González, M.; Malhotra, S.; Jiménez-Arranz, Ó.; Enke, H.; Casamiquela, L.; Ardèvol, J. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost".Astronomy and Astrophysics .691 : A98.arXiv :2407.06963 Bibcode :2024A&A...691A..98K .doi :10.1051/0004-6361/202451427 . ^a b Fetherolf, Tara; Pepper, Joshua; Simpson, Emilie; Kane, Stephen R.; Močnik, Teo; English, John Edward; Antoci, Victoria; Huber, Daniel; Jenkins, Jon M.; Stassun, Keivan; Twicken, Joseph D.; Vanderspek, Roland; Winn, Joshua N. (2023)."Variability Catalog of Stars Observed during the TESS Prime Mission" .The Astrophysical Journal Supplement Series .268 (1): 4.arXiv :2208.11721 Bibcode :2023ApJS..268....4F .doi :10.3847/1538-4365/acdee5 ^a b c "42 Her" .SIMBAD Centre de données astronomiques de Strasbourg . Retrieved2019-06-13 .^ 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 . ^ Percy, J. R.; Shepherd, C. W. (October 1992), "Photometric Survey of Small-Amplitude Red Variables",Information Bulletin on Variable Stars ,3792 : 1,Bibcode :1992IBVS.3792....1P . ^ Famaey, B.; et al. (2009), "Spectroscopic binaries among Hipparcos M giants. I. Data, orbits, and intrinsic variations",Astronomy and Astrophysics ,498 (2):627– 640,arXiv :0901.0934 Bibcode :2009A&A...498..627F ,doi :10.1051/0004-6361/200810698 ,S2CID 18739721 . ^ Ortiz, Roberto; Guerrero, Martín A. (September 2016), "Ultraviolet emission from main-sequence companions of AGB stars",Monthly Notices of the Royal Astronomical Society ,461 (3): 3036,arXiv :1606.09086 Bibcode :2016MNRAS.461.3036O ,doi :10.1093/mnras/stw1547 S2CID 118619933 .
