17 Comae Berenices

Multiple star system in the constellation Coma Berenices Coma Berenices IAU.svg center 300 right Red circle.svg 10 17 Com 63.0 40.5 Location of 17 Com (circled) J2000.0 Coma Berenices 17 Com A 12 28 54.702 +25 54 46.27 5.242 0.004 17 Com B 12 28 44.565 +25 53 57.56 6.635 17 Com C 12 28 44.579 +25 53 56.00 13.7 17 Com A A0pA0 SrCrEu −0.056 0.009 α2 CVn + δ Sct(?) 17 Com B main sequence kA2hA9VmF0 0.216 0.084 17 Com A −1.4 0.5 −23.071 −15.110 12.9991 0.3721 0.98 17 Com B −1.8 0.1 −22.231 −17.055 13.9752 0.0872 2.46 17 Com B 17 Com C 68.290 0.012 days 0.296 0.008 2448313.4 0.4 JD commas 260.7 2.2 14.0 0.2 17 Com A 2.38 solar mass2.61 solar mass2.75 0.3 2.09 42.7 4.27 cgs3.70 0.20 10212 K commas9309 250 commas 20.4 0.4 101 y 17 Com B 1.74 0.6 8068 200 commas 8.9 1.7 4.29 0.20 22 17 Com C 0.61 4,107 0.101 0.62 BU 1080 8568 17 Com J12289+2555 17 Com A AI Com +26°2354 108662 60904 4752 82330 17012 17 Com B +26°2353 108651 60891 4751 82328 17007 17+Com 17 Com A HD+108651 17 Com B HD+108651B 17 Com C 17 Comae Berenices (17 Com) is a multiple star system in the northern constellation of Coma Berenices. The brighter component, 17 Com A, is a naked eye star with an apparent visual magnitude of 5.2. It has a companion of magnitude 6.6, 17 Com B, positioned at an angular separation of 146.4 arcsecond along a position angle of 251°, as of 2018, and a 14th-magnitude companion 1.4 " from 17 Com B. They are located at a distance of approximately 240 light years from the Sun based on parallax measurements. 1 , - S3 A 0 ! PC 145" 1 - ( , - S4 Ba 0 ! , ( PA 68.3 days 1 ` ( ` - S4 Bb 0 ! PA 1.4" 1 ` - S1 C Hierarchy of orbits in the 14 Ceti system The double nature of this system was documented by F. G. W. Struve in 1836. The pair share a common proper motion through space and thus may be associated. Component B is itself a binary star system, although only the brighter component is visible in the spectrum. The Washington Double Star Catalogue lists the companion as component C, with a magnitude of 13.7 and a separation of 1.4 arcsecond. The 17 Com stars have been recognized as members of the Coma Star Cluster, but this is disputed. The star 17 Com A was classified as chemically peculiar by A. J. Cannon prior to 1918. W. W. Morgan in 1932 found the star's spectral lines varied in strength and appearance, and detected lines of the element europium. H. W. Babcock and T. G. Cowling measured the Zeeman effect in this star, demonstrating in 1953 that it has a magnetic field. In 1967, E. P. J. van den Heuvel noted the blue excess of this star, suggesting it is a blue straggler. G. W. Preston and associates in 1969 found that the luminosity and magnetic field of this star varied in strength with a time scale of around five days. thumb|left|A light curve for AI Comae Berenices, plotted from TESS data 17 Com A is a magnetic chemically peculiar Ap star with a stellar classification of A0p or A0 SrCrEu, with the latter indicating the spectrum shows abundance anomalies of the elements strontium, chromium, and europium. The level of silicon in the atmosphere is also enhanced and it shows a significant helium deficiency. It has the variable star designation of AI Com, and is classified as an Alpha2 Canum Venaticorum variable and a suspected Delta Scuti variable. It has been identified as a suspected blue straggler. The primary has an estimated age of 101 million years and is spinning with a projected rotational velocity of 20 km/s. It has more than double the mass and twice the radius of the Sun. The magnetic field strength is 3300 150 G commas. It is radiating 43 times the luminosity of the Sun from its photosphere at an effective temperature of around 10,000 K. The co-moving companion, component B, is a single-lined spectroscopic binary with an orbital period of 68.3 days and an eccentricity (ovalness) of 0.3. The visible member of this binary pair is a strong Am star with a class of kA2hA9VmF0, indicating it has the Calcium K-lines of an A0 star, the hydrogen lines of an A9 star, and the metallic lines of an F0 star. References 3960724252307532672 3960724286666918016 3960724286666184576 HD 108662 2022-01-14 HD 108651 2022-01-14 Tokovinin Andrei The Updated Multiple Star Catalog The Astrophysical Journal Supplement Series 2018 235 1 6 10.3847/1538-4365/aaa1a5 free 1712.04750 2018ApJS..235....6T Hardegree-Ullman Kevin K. Apai Dániel Bergsten Galen J. Pascucci Ilaria López-Morales Mercedes Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets The Astronomical Journal 2023 165 6 267 10.3847/1538-3881/acd1ec free 2304.12490 2023AJ....165..267H MAST: Barbara A. 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Kaler 17 Comae Berenices Stars July 25, 2014 http://stars.astro.illinois.edu/sow/17com.html 2022-01-17 Category:A-type main-sequence stars Category:Magnetic chemically peculiar stars Category:Am stars Category:Alpha2 Canum Venaticorum variables Category:Delta Scuti variables Category:Spectroscopic binaries Category:Triple stars Category:Coma Berenices 4752 +26 2353 Comae Berenices, 17 108662 060904 Comae Berenices, AI Category:A0 stars