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9 Aurigae

Location of 9 Aurigae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Auriga
Right ascension	05 06 40.62967
Declination	+51° 35′ 51.8025″
Apparent magnitude (V)	4.93 - 5.03
Characteristics
Spectral type	F2V
U−B color index	-0.03
B−V color index	+0.34
Variable type	γ Dor
Astrometry
A
Radial velocity (Rv)	−0.47±0.57 km/s
Proper motion (μ)	RA: −28.557 mas/yr Dec.: −171.822 mas/yr
Parallax (π)	37.0551 ± 0.1371 mas
Distance	88.0 ± 0.3 ly (26.99 ± 0.10 pc)
B
Proper motion (μ)	RA: −54.582 mas/yr Dec.: −156.009 mas/yr
Parallax (π)	37.0796 ± 0.0631 mas
Distance	88.0 ± 0.1 ly (26.97 ± 0.05 pc)
C
Radial velocity (Rv)	−1.88±0.17 km/s
Proper motion (μ)	RA: −32.386 mas/yr Dec.: −173.026 mas/yr
Parallax (π)	37.2115 ± 0.0184 mas
Distance	87.65 ± 0.04 ly (26.87 ± 0.01 pc)
Orbit
Period (P)	391.7 d
Eccentricity (e)	0.37
Semi-amplitude (K1) (primary)	5.8 km/s
Details
A
Mass	1.97 M☉
Radius	1.56 R☉
Luminosity	6.042 L☉
Surface gravity (log g)	4.07 cgs
Temperature	7,023 K
Metallicity	−0.12 dex
Rotational velocity (v sin i)	21.0 km/s
B
Mass	0.49 M☉
Temperature	4,947 K
C
Mass	0.751 M☉
Radius	0.756 R☉
Luminosity	0.162 L☉
Temperature	4,633 K
Other designations
V398 Aur, BD+51°1024, GJ 9174, HD 32537, HIP 23783, HR 1637, SAO 25019
Database references
SIMBAD	9 Aur A
	9 Aur B
	9 Aur C

9 Aurigae (9 Aur) is a star system in Auriga (constellation). It has an apparent magnitude of about 5, making it visible to the naked eye in many suburban skies. Parallax estimates made by the Hipparcos spacecraft put it at about 86 light-years (26 parsecs) from the solar system, although individual Gaia Data Release 3 parallaxes place all three components at 88 light years.

Kevin Krisciunas and Edward Francis Guinan discovered that the star is a variable star in 1990. It is a well-studied Gamma Doradus variable, and was one of the first stars to be so-classified. This star type varies in luminosity due to non-radial pulsations. Its apparent magnitude varies from 4.93 to 5.03 over a period of 1.25804 days. For that reason it was given the variable star designation V398 Aurigae in 1995.

9 Aurigae is a multiple star system. The naked-eye component A is a single-lined spectroscopic binary. Only the signature of an F-type main sequence star can be seen in the spectrum, but the periodic doppler shift of the absorption lines demonstrates that there is a hidden companion in a 391.7-day orbit. The gravitational interaction of the two bodies produces variations in their respective motions, which is what creates the doppler shift.

Four other companions to 9 Aurigae are listed in multiple star catalogs. The closest companion is a 12th-magnitude red dwarf 5″ away. 90″ away is component C, a 9th-magnitude star with a spectral class of K5Ve, which may also be a spectroscopic binary. Further-separated still is a 14th-magnitude star, component D, proposed to be a more distant red giant, although Gaia astrometry places it at a similar distance and with a similar proper motion. The most widely-separated companion is component E, a distant unrelated star.

References

1. ^ van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
2. ^ 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. Bibcode:2009yCat....102025S.
3. Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
4. ^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
5. ^ Rachford, Brian L.; Foight, Dillon R. (2009). "Chromospheric Variability in Early F-Type Stars". The Astrophysical Journal. 698 (1): 786–802. arXiv:0904.1620. Bibcode:2009ApJ...698..786R. doi:10.1088/0004-637X/698/1/786. S2CID 693296.
6. ^ 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 at VizieR.
7. ^ 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 at VizieR.
8. ^ 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 at VizieR.
9. ^ Abt, Helmut A. (1965). "The Frequency of Binaries among Normal A-Type Stars". The Astrophysical Journal Supplement Series. 11: 429. Bibcode:1965ApJS...11..429A. doi:10.1086/190120.
10. ^ "HR 1637". Multiple Star Catalog. Archived from the original on 2020-09-16. Retrieved 2019-10-09.
11. 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.
12. 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.
13. ^ Newton, Elisabeth R.; Irwin, Jonathan; Charbonneau, David; Berlind, Perry; Calkins, Michael L.; Mink, Jessica (2017). "The Hα Emission of Nearby M Dwarfs and its Relation to Stellar Rotation". The Astrophysical Journal. 834 (1): 85. arXiv:1611.03509. Bibcode:2017ApJ...834...85N. doi:10.3847/1538-4357/834/1/85. S2CID 55000202.
14. ^ 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.
15. Bortle, John E. (February 2001). "The Bortle Dark-Sky Scale". Sky & Telescope. Sky Publishing Corporation. Retrieved 15 May 2017.
16. Krisciunas, K.; Aspin, C.; Geballe, T. R.; Akazawa, H.; Claver, C. F.; Guinan, E. F.; Landis, H. J.; Luedeke, K. D.; Ohkura, N.; Ohshima, O.; Skillman, D. R. (August 1993). "The 9 Aurigae system". Monthly Notices of the Royal Astronomical Society. 263 (3): 781–788. arXiv:astro-ph/9304008. Bibcode:1993MNRAS.263..781K. doi:10.1093/mnras/263.3.781.
17. Krisciunas, K.; Guinan, E. (August 1990). "Unexplained Light Variations of the F0 V Star 9 Aurigae" (PDF). Information Bulletin on Variable Stars. 3511: 1–7. Bibcode:1990IBVS.3511....1K. Retrieved 1 December 2024.
18. ^ Krisciunas, K.; Griffin, R. F.; Guinan, E. F.; Luedeke, K. D.; McCook, G. P. (1995). "9 Aurigae: Strong evidence for non-radial pulsations". Monthly Notices of the Royal Astronomical Society. 273 (3): 662. arXiv:astro-ph/9407094. Bibcode:1995MNRAS.273..662K. doi:10.1093/mnras/273.3.662. S2CID 117588180.
19. Kazarovets, E. V.; Samus, N. N. (January 1995). "The 72nd Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 4140: 1–28. Bibcode:1995IBVS.4140....1K. Retrieved 1 December 2024.
20. Dommanget, J.; Nys, O. (1994). "Catalogue des composantes d'etoiles doubles et multiples (CCDM) premiere edition - Catalogue of the components of double and multiple stars (CCDM) first edition". Com. De l'Observ. Royal de Belgique. 115: 1. Bibcode:1994CoORB.115....1D.
21. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
22. Alonso-Floriano, F. J.; Morales, J. C.; Caballero, J. A.; Montes, D.; Klutsch, A.; Mundt, R.; Cortés-Contreras, M.; Ribas, I.; Reiners, Ansgar; Amado, P. J.; Quirrenbach, A.; Jeffers, S. V. (2015). "CARMENES input catalogue of M dwarfs". Astronomy & Astrophysics. 577: A128. arXiv:1502.07580. Bibcode:2015A&A...577A.128A. doi:10.1051/0004-6361/201525803. S2CID 53135130.
23. ^ Krisciunas, K.; Aspin, C.; Geballe, T. R.; Akazawa, H.; Claver, C. F.; Guinan, E. F.; Landis, H. J.; Luedeke, K. D.; Ohkura, N.; Ohshima, O.; Skillman, D. R. (1993). "The 9 Aurigae system". Monthly Notices of the Royal Astronomical Society. 263 (3): 781–788. arXiv:astro-ph/9304008. Bibcode:1993MNRAS.263..781K. doi:10.1093/mnras/263.3.781. S2CID 18596475.
24. 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 at VizieR.
25. 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.

v t e Constellation of Auriga
Auriga in Chinese astronomy List of stars in Auriga
Stars	Bayer α (Capella) β (Menkalinan) γ (Elnath) δ ε (Almaaz) ζ (Saclateni) η (Haedus) θ (Mahasim) ι (Hassaleh) κ λ (Alhurr) μ ν ξ ο π ρ σ τ υ φ χ ψ ψ ψ ψ ψ ψ ψ ψ ψ ω Flamsteed 2 5 6 9 12 14 16 18 19 22 26 28 36 38 39 40 41 42 43 45 47 49 51 53 54 59 60 62 63 64 65 66 35 Cam Variable R T RT (48) RW SU UU WW AB AE AR (17) EO IQ IU LY MZ NO NY PU QZ V352 V361 V394 V420 V433 V538 HR 1558 1615 1738 1752 1794 1795 1822 1825 1866 1884 1938 1945 2028 2096 2137 HD 33203 33463 35619 43691 45350 (Lucilinburhuc) 49674 (Nervia) Other Gliese 268 HAT-P-9 (Tevel) KELT-2 MWC 480 SGR 0501+4516 UGPS J0521+3640 WASP-12
Exoplanets HAT-P-9b (Alef) HD 40979 b HD 43691 b HD 45350 b HD 49674 b KELT-2Ab WASP-12b
Star clusters	NGC 1664 1893 1907 1931 2240 2281 Other Messier 36 Messier 37 Messier 38 Palomar 2
Nebulae	NGC 1985 2242 Other IC 405 IC 2149 Westbrook Nebula
Galaxies 3C 147 4C +41.17 DA 193 MCG +08-11-011
Galaxy clusters MACS J0717.5+3745
Category

• Flamsteed objects
• Durchmusterung objects
• Gliese and GJ objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects
• Spectroscopic binaries
• Multiple star systems
• Auriga
• Gamma Doradus variables
• F-type main-sequence stars
• Objects with variable star designations