Publication Year 2017 Acceptance in OA@INAF 2020-09-16T10:52:35Z Title Estimates of Active Region Area Coverage through Simultaneous Measurements þÿof the He I »» 5876 and 10830 Lines Authors ANDRETTA, Vincenzo; Giampapa, Mark S.; COVINO, Elvira; Reiners, Ansgar; Beeck, Benjamin DOI 10.3847/1538-4357/aa6a14 Handle http://hdl.handle.net/20.500.12386/27409 Journal THE ASTROPHYSICAL JOURNAL Number 839 The Astrophysical Journal, 839:97 (18pp), 2017 April 20 https://doi.org/10.3847/1538-4357/aa6a14 © 2017. The American Astronomical Society. All rights reserved. Estimates of Active Region Area Coverage through Simultaneous Measurements of the He I λλ 5876 and 10830 Lines Vincenzo Andretta1,5, Mark S. Giampapa2,6, Elvira Covino1, Ansgar Reiners3, and Benjamin Beeck4,5 1 INAF—Osservatorio Astronomico di Capodimonte Salita Moiariello, 16 I-80131 Naples, Italy;
[email protected] 2 National Solar Observatory 950 N.Cherry Avenue Tucson, AZ85719, USA 3 Institut für Astrophysik Georg-August-Universität Göttingen Friedrich-Hund-Platz 1 D-37077 Göttingen, Germany 4 Max Planck Institute for Solar System Research Justus-von-Liebig-Weg 3 D-37077 Göttingen, Germany Received 2016 July 29; revised 2017 March 24; accepted 2017 March 27; published 2017 April 20 Abstract Simultaneous, high-quality measurements of the neutral helium triplet features at 5876 Å and 10830 Å in a sample of solar-type stars are presented. The observations were made with ESO telescopes at the La Silla Paranal Observatory under program ID 088.D-0028(A) and MPG Utility Run for Fiber Extended-range Optical Spectrograph 088.A-9029(A). The equivalent widths of these features combined with chromospheric models are utilized to infer the fractional area coverage, or filling factor, of magnetic regions outside of spots.