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标题：Temporal changes of the flare activity of Proxima Centauri ★
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作者：Ya. V. Pavlenko ; A. Suárez Mascareño ; M. R. Zapatero Osorio 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：626
DOI：10.1051/0004-6361/201834258
语种：English
出版社：EDP Sciences
摘要：Context.We study temporal variations of the emission lines of Hα, Hɛ, H and K CaII, D1and D2NaI, He4026, and He5876in the HARPS spectra of Proxima Centauri across an extended time of 13.2 yr, from May 27, 2004 to September 30, 2017.Aims.We analyse the common behaviour and differences in the intensities and profiles of different emission lines in flare and quiet modes of Proxima activity.Methods.We compare the pseudo-equivalent widths (pEW) and profiles of the emission lines in the HARPS high-resolution (R~ 115 000) spectra observed at the same epochs.Results.All emission lines show variability with a timescale of at least 10 min. The strength of all lines except He4026correlate with Hα. During strong flares the “red asymmetry” appears in the Hαemission line indicating the infall of hot condensed matter into the chromosphere with velocities greater than 100 km s−1disturbing chromospheric layers. As a result, the strength of the CaII lines anti-correlates with Hαduring strong flares. The HeI lines at 4026 and 5876 Å appear in the strong flares. The cores of D1and D2NaI lines are also seen in emission. During the minimum activity of Proxima Centauri, CaII lines and Hɛalmost disappear while the blue part of the NaI emission lines is affected by the absorption in the extending and condensing flows.Conclusions.We see different behaviour of emission lines formed in the flare regions and chromosphere. Chromosphere layers of Proxima Cen are likely heated by the flare events; these layers are cooled in the “non-flare” mode. The self-absorption structures in cores of our emission lines vary with time due to the presence of a complicated system of inward and outward matter flows in the absorbing layers.
关键词：Key wordsenstars: activitystars: atmospheresstars: chromospheresstars: flarestars: individual: Proxima Cen