C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST01:16:25

2019A&A...626A.111P - Astronomy and Astrophysics, volume 626A, 111-111 (2019/6-1)

Temporal changes of the flare activity of Proxima Centauri.


Abstract (from CDS):

Context. We study temporal variations of the emission lines of Hα, He, H and K CaII, D1 and D2 NaI, He4026, and He5876 in the HARPS spectra of Proxima Centauri across an extended time of 13.2yr, 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∼115000) 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 He4026 correlate with Hα. During strong flares the "red asymmetry" appears in the Hα emission line indicating the infall of hot condensed matter into the chromosphere with velocities greater than 100km/s disturbing chromospheric layers. As a result, the strength of the CaII lines anti-correlates with Hα during strong flares. The HeI lines at 4026 and 5876 Å appear in the strong flares. The cores of D1 and D2 NaI lines are also seen in emission. During the minimum activity of Proxima Centauri, CaII lines and He almost 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.

Abstract Copyright: © ESO 2019

Journal keyword(s): stars: activity - stars: atmospheres - stars: chromospheres - stars: flare - stars: individual: Proxima Cen

VizieR on-line data: <Available at CDS (J/A+A/626/A111): tablea1.dat>

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
1 CoRoT-7b Pl 06 43 49.4690410679 -01 03 46.825797768           ~ 346 1
2 V* YZ CMi Er* 07 44 40.1726285952 +03 33 08.877830321 13.761 12.831 11.225 9.958 8.263 M4.0Ve 782 0
3 V* V645 Cen Er* 14 29 42.9451234609 -62 40 46.170818907 14.21 12.95 11.13 9.45 7.41 M5.5Ve 957 0
4 NAME V645 Cen b Pl 14 29 42.9451234609 -62 40 46.170818907           ~ 204 0
5 NAME Barnard's star BY* 17 57 48.4997994034 +04 41 36.111354228 12.497 11.24 9.511 8.298 6.741 M4V 654 2
6 G 208-42 Fl* 19 51 09.3205269987 +46 29 00.208931632   14.47   12.544   M4.0V 106 0

    Equat.    Gal    SGal    Ecl

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