Astronomy:HR 4098

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Short description: Binary star system in the constellation Ursa Major

Coordinates: Sky map 10h 28m 03.8821s, +48° 47′ 05.6554″

HR 4098
Observation data
{{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000      [[Astronomy:Equinox (celestial coordinates)|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±0.03[2] mas/yr
Dec.: -896.055±0.04[2] mas/yr
Parallax (π)43.4944 ± 0.0386[2] mas
Distance74.99 ± 0.07 ly
(22.99 ± 0.02 pc)
HD 90508B
Proper motion (μ) RA: +81.80±0.03 mas/yr
Dec.: −880.66±0.03 mas/yr
Parallax (π)43.4822 ± 0.0452[4] mas
Distance75.01 ± 0.08 ly
(23.00 ± 0.02 pc)
Orbit[7]
PrimaryHD 90508A
CompanionHD 90508B
Period (P)590±208 yr
Semi-major axis (a)4.67±0.12"
(107 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
Mass0.86±0.03 M☉
Radius1.12±0.03 R☉
Surface gravity (log g)4.3±0.1 cgs
Temperature5720±100 K
Metallicity [Fe/H]−0.23[9] dex
Rotation18.0±2.7 d[10]
Rotational velocity (v sin i)1.0[10] km/s
Age10.5±2[11] Gyr
HD 90508B
Mass0.25±0.01 M☉
Other designations
BD+49 1961, GJ 392, HD 90508, HIP 51248, HR 4098, WDS J10281+4847, GSC 08176-00283, 2MASS J10280388+4847067[12]
HD 90508A: TYC 8176-283-1, LHS 2267, LTT 12795, NLTT 24398
HD 90508B: LHS 2266, NLTT 24397
Database references
SIMBADdata
A
B

HR 4098, also known as HD 90508, is a binary star system in the northern constellation of Ursa Major at a distance of 75 light years. This object is barely visible to the naked eye as a dim, yellow star with an apparent visual magnitude of 6.45. It is approaching the Earth with a heliocentric radial velocity of 7.2±0.2 km/s.[2]

The star system is a visual binary with a 3.466 seconds of arc projected separation,[13] identified as such in 1994–1997.[7][13] The orbit of the binary is wide and highly uncertain[13] due to the long period and high inclination.[7]

The larger star, HD 90508A, is a very old main-sequence star approaching a turn-off from the main sequence.[5] Very little dust remains in the stellar system, therefore the starlight of HR 4098 is one of the standards for non-polarized emission, polarization being below 0.2% in all bands.[14] Unlike the majority of G-class stars, HD 90508A has a direct correlation between brightness and stellar activity. This behavior is shared with HD 88986 and the Sun.[15]

Very little is known about the companion, which could be a K-class or M-class dwarf star.[8]

References

  1. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 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. doi:10.1086/510356. ISSN 0004-6256. Bibcode: 2007AJ....133..862H. 
  4. ↑ 4.0 4.1 4.2 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  5. ↑ 5.0 5.1 Fuhrmann, K.; Chini, R.; Buda, L. -S.; Pozo Nuñez, F. (2014). "On the Age of Gliese 86". The Astrophysical Journal 785 (1): 68. doi:10.1088/0004-637X/785/1/68. Bibcode: 2014ApJ...785...68F. 
  6. ↑ 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. doi:10.1086/378365. Bibcode: 2003AJ....126.2048G. 
  7. ↑ 7.0 7.1 7.2 Drummond, Jack D. (11 February 2014). "Binary Stars Observed with Adaptive Optics at the Starfire Optical Range". The Astronomical Journal 147 (3): 65. doi:10.1088/0004-6256/147/3/65. ISSN 0004-6256. Bibcode: 2014AJ....147...65D. 
  8. ↑ 8.0 8.1 Hirsch, Lea A.; Rosenthal, Lee; Fulton, Benjamin J.; Howard, Andrew W.; Ciardi, David R.; Marcy, Geoffrey W.; Nielsen, Eric; Petigura, Erik A. et al. (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. doi:10.3847/1538-3881/abd639. ISSN 0004-6256. Bibcode: 2021AJ....161..134H. 
  9. ↑ Van Hamme, W.; Wilson, R. E. (1986). "Close Binary Mass Anomalies and Metallicity". The Astrophysical Journal 307: 151. doi:10.1086/164403. Bibcode: 1986ApJ...307..151V. 
  10. ↑ 10.0 10.1 Justesen, A. B.; Albrecht, S. (2020). "The spin-orbit alignment of visual binaries". Astronomy & Astrophysics 642: A212. doi:10.1051/0004-6361/202039138. Bibcode: 2020A&A...642A.212J. 
  11. ↑ 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. doi:10.1088/0067-0049/211/1/9. Bibcode: 2014ApJS..211....9L. 
  12. ↑ "HD 90508". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+90508. 
  13. ↑ 13.0 13.1 13.2 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. doi:10.2298/SAJ0774083C. Bibcode: 2007SerAJ.174...83C. 
  14. ↑ Goswami, A.; Karinkuzhi, D. (2012). "Polarimetric studies of carbon stars at high Galactic latitude". Astronomy & Astrophysics 549: A68. doi:10.1051/0004-6361/201219911. 
  15. ↑ 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. doi:10.1088/0004-6256/138/1/312. Bibcode: 2009AJ....138..312H. 



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