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Absolute Dimensions Of The G7+K7 Eclipsing Binary Star Im Virginis: Discrepancies With Stellar Evolution Models, Juan Carlos Morales, Guillermo Torres, Laurence A. Marschall, William C. Brehm
Absolute Dimensions Of The G7+K7 Eclipsing Binary Star Im Virginis: Discrepancies With Stellar Evolution Models, Juan Carlos Morales, Guillermo Torres, Laurence A. Marschall, William C. Brehm
Physics and Astronomy Faculty Publications
We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined eclipsing binary IMVir, composed of a G7-type primary and a K7 secondary.With these observations, we derive accurate absolute masses and radii of M1 = 0.981 + 0.012M, M2 = 0.6644 + 0.0048M, R1 = 1.061 + 0.016R, and R2 = 0.681 + 0.013R for the primary and secondary, with relative errors under 2%. The effective temperatures are 5570 + 100 K and 4250 + 130 K, respectively. The significant difference in mass makes this a favorable case for comparison with stellar evolution theory.We find that …
Rotational Periods And Starspot Activity Of Young Solar-Type Dwarfs In The Open Cluster Ic 4665, S. Allain, C. Prosser, Laurence A. Marschall, Bentley D. Laaksonen
Rotational Periods And Starspot Activity Of Young Solar-Type Dwarfs In The Open Cluster Ic 4665, S. Allain, C. Prosser, Laurence A. Marschall, Bentley D. Laaksonen
Physics and Astronomy Faculty Publications
We present the results of a V-band photometric monitoring survey of 15 late-type dwarfs in the young open cluster IC 4665. Low-amplitude periodic light variations are found for 8 stars and ascribed to the modulation by starspots that cover typically a few percent of the stellar disk. Periods range from 0.6 to 3.7d, translating to equatorial velocities between 13 and 93 km.s-1. That no period longer than 4d was detected suggests a relative paucity of extremely slow rotators (Veq << 10 km.s-1) among late-type dwarfs in IC 4665. The fractional number of slow rotators in IC 4665 is similar to that of Alpha Per cluster, suggesting that IC 4665 is close in age to Alpha Per (~50 Myr).