Binary star system in the constellation Ursa Major
HR 4098 Observation dataEpoch J2000 Equinox J2000 Constellation Ursa Major [ 1] A Right ascension 10h 28m 03.88293s [ 2] Declination +48° 47′ 05.6436″[ 2] Apparent magnitude (V)6.45[ 3] B Right ascension 10h 28m 04.03128s [ 4] Declination +48° 47′ 09.5442″[ 4] Apparent magnitude (V)6.45[ 3] Characteristics Evolutionary stage main sequence [ 5] Spectral type G0V[ 6] Astrometry HD 90508A Radial velocity (Rv )7.2± 0.2[ 2] km/s Proper motion (μ)RA: 83.79± 0.03mas /yr [ 2] Dec.: -896.055± 0.04mas /yr [ 2] Parallax (π)43.4944± 0.0386 mas [ 2] Distance 74.99 ± 0.07 ly pc ) HD 90508B Proper motion (μ)RA: +81.80± 0.03mas /yr [ 4] Dec.: −880.66± 0.03mas /yr [ 4] Parallax (π)43.4822± 0.0452 mas [ 4] Distance 75.01 ± 0.08 ly pc ) Orbit [ 7] Primary HD 90508A Companion HD 90508B Period (P)590± 208 yr Semi-major axis (a)4.67± 0.12"AU ) Eccentricity (e)0 Inclination (i)81.4± 3.5° Longitude of the node (Ω)16.5± 1.9° Periastron epoch (T)1958.6± 16.8 Details[ 8] HD 90508A Mass 0.86± 0.03 M ☉ Radius 1.12± 0.03 R ☉ Surface gravity (log g )4.3± 0.1 cgs Temperature 5720± 100 K Metallicity [Fe/H] −0.23[ 9] dex Rotation 18.0± 2.7d [ 10] Rotational velocity (v sin i )1.0[ 10] Age 10.5± 2[ 11] Gyr HD 90508B Mass 0.25± 0.01 M ☉ Other designations BD +49 1961GJ 392HD 90508HIP 51248HR 4098WDS J10281+4847GSC 08176-002832MASS J10280388+4847067[ 12] HD 90508A : TYC 8176-283-1, LHS 2267, LTT 12795, NLTT 24398HD 90508B : LHS 2266, NLTT 24397Database references SIMBAD data A B
HR 4098 , also known as HD 90508, is abinary star system in the northernconstellation ofUrsa Major at a distance of 75 light years . This object is barely visible to the naked eye as a dim, yellow star with anapparent visual magnitude of 6.45. It is approaching the Earth with a heliocentricradial velocity of± 0.2 km/s[ 2]
The star system is a visual binary with a 3.466seconds of arc projected separation,[ 13] [ 7] [ 13] [ 13] [ 7]
The larger star, HD 90508A, is a very oldmain-sequence star approaching a turn-off from the main sequence.[ 5] [ 14] HD 88986 and theSun .[ 15]
Very little is known about the companion, which could be a K-class or M-class dwarf star.[ 8]
^ 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 . ^a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023)."Gaia Data Release 3. Summary of the content and survey properties" .Astronomy and Astrophysics .674 : A1.arXiv :2208.00211 Bibcode :2023A&A...674A...1G .doi :10.1051/0004-6361/202243940 S2CID 244398875 . Gaia DR3 record for this source atVizieR .^a b Hall, Jeffrey C.; Lockwood, G. W.; Skiff, Brian A. (23 January 2007). "The Activity and Variability of the Sun and Sun-like Stars. I. Synoptic Ca II H and K Observations".The Astronomical Journal .133 (3):862– 881.Bibcode :2007AJ....133..862H .doi :10.1086/510356 .eISSN 1538-3881 .ISSN 0004-6256 .S2CID 121460023 . ^a b c d Vallenari, A.; et al. (Gaia collaboration) (2023)."Gaia Data Release 3. Summary of the content and survey properties" .Astronomy and Astrophysics .674 : A1.arXiv :2208.00211 Bibcode :2023A&A...674A...1G .doi :10.1051/0004-6361/202243940 S2CID 244398875 . Gaia DR3 record for this source atVizieR .^a b Fuhrmann, K.; Chini, R.; Buda, L. -S.; Pozo Nuñez, F. (2014). "On the Age of Gliese 86".The Astrophysical Journal .785 (1): 68.Bibcode :2014ApJ...785...68F .doi :10.1088/0004-637X/785/1/68 . ^ Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I.".The Astronomical Journal .126 (4): 2048.arXiv :astro-ph/0308182 Bibcode :2003AJ....126.2048G .doi :10.1086/378365 . ^a b c Drummond, Jack D. (11 February 2014)."Binary Stars Observed with Adaptive Optics at the Starfire Optical Range" .The Astronomical Journal .147 (3): 65.Bibcode :2014AJ....147...65D .doi :10.1088/0004-6256/147/3/65 eISSN 1538-3881 .ISSN 0004-6256 . ^a b Hirsch, Lea A.; Rosenthal, Lee; Fulton, Benjamin J.; Howard, Andrew W.; Ciardi, David R.; Marcy, Geoffrey W.; Nielsen, Eric; Petigura, Erik A.; de Rosa, Robert J.; Isaacson, Howard; Weiss, Lauren M.; Sinukoff, Evan; Macintosh, Bruce (22 February 2021)."Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc" .The Astronomical Journal .161 (3): 134.arXiv :2012.09190 Bibcode :2021AJ....161..134H .doi :10.3847/1538-3881/abd639 eISSN 1538-3881 .ISSN 0004-6256 . ^ Van Hamme, W.; Wilson, R. E. (1986). "Close Binary Mass Anomalies and Metallicity".The Astrophysical Journal .307 : 151.Bibcode :1986ApJ...307..151V .doi :10.1086/164403 . ^a b Justesen, A. B.; Albrecht, S. (2020). "The spin-orbit alignment of visual binaries".Astronomy & Astrophysics .642 : A212.arXiv :2008.12068 Bibcode :2020A&A...642A.212J .doi :10.1051/0004-6361/202039138 .S2CID 221340982 . ^ Loyd, R. O. Parke; France, Kevin (2014). "Fluctuations and Flares in the Ultraviolet Line Emission of Cool Stars: Implications for Exoplanet Transit Observations".The Astrophysical Journal Supplement Series .211 (1): 9.arXiv :1402.0073 Bibcode :2014ApJS..211....9L .doi :10.1088/0067-0049/211/1/9 .S2CID 118394892 . ^ "HD 90508" .SIMBAD Centre de données astronomiques de Strasbourg . RetrievedDecember 20, 2021 .^a b c Cvetkovic, Z.; Pavlovic, R.; Strigachev, A.; Novakovic, B.; Popovic, G. M. (2007)."CCD Measurements of Double and Multiple Stars at NAO Rozhen. III" .Serbian Astronomical Journal .174 (174): 83.Bibcode :2007SerAJ.174...83C .doi :10.2298/SAJ0774083C ^ Goswami, A.; Karinkuzhi, D. (2012). "Polarimetric studies of carbon stars at high Galactic latitude".Astronomy & Astrophysics .549 : A68.arXiv :1212.4276 doi :10.1051/0004-6361/201219911 .S2CID 118393046 . ^ Hall, Jeffrey C.; Henry, Gregory W.; Lockwood, G. Wesley; Skiff, Brian A.; Saar, Steven H. (2009). "The Activity and Variability of the Sun and Sun-Like Stars. II. Contemporaneous Photometry and Spectroscopy of Bright Solar Analogs".The Astronomical Journal .138 (1): 312.Bibcode :2009AJ....138..312H .doi :10.1088/0004-6256/138/1/312 .
