2017A&A...606A..49P


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST15:34:02

2017A&A...606A..49P - Astronomy and Astrophysics, volume 606A, 49-49 (2017/10-1)

Flare activity and photospheric analysis of Proxima Centauri.

PAVLENKO Y., SUAREZ MASCARENO A., REBOLO R., LODIEU N., BEJAR V.J.S. and GONZALEZ HERNANDEZ J.I.

Abstract (from CDS):

Context. We present the analysis of emission lines in high-resolution optical spectra of the planet-host star Proxima Centauri (Proxima) classified as a M5.5V.
Aims. We carry out a detailed analysis of the observed spectra to get a better understanding of the physical conditions of the atmosphere of this star.
Methods. We identify the emission lines in a series of 147 high-resolution optical spectra of the star at different levels of activity and compare them with the synthetic spectra computed over a wide spectral range.
Results. Our synthetic spectra computed with the PHOENIX 2900/5.0/0.0 model atmosphere fits the observed spectral energy distribution from optical to near-infrared quite well. However, modelling strong atomic lines in the blue spectrum (3900-4200Å) requires implementing additional opacity. We show that high-temperature layers in Proxima Centauri consist of at least three emitting parts: a) a stellar chromosphere where numerous emission lines form; we suggest that some emission cores of strong absorption lines of metals form there; b) flare regions above the chromosphere, where hydrogen Balmer lines up to high transition levels (10-2) form; and c) a stellar wind component with Vr=-30km/s seen in some Balmer lines as blueshifted emission lines. We believe that the observed He line at 4026Å in emission can be formed in that very hot region.
Conclusions. We show that the real structure of the atmosphere of Proxima is rather complicated. The photosphere of the star is best fit by a normal M5 dwarf spectrum. On the other hand, emission lines form in the chromosphere, flare regions, and extended hot envelope.

Abstract Copyright: © ESO, 2017

Journal keyword(s): stars: individual: Proxima Cen - stars: atmospheres - stars: abundances - stars: activity - stars: flare - stars: fundamental parameters - stars: fundamental parameters

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * alf Boo RG* 14 15 39.67207 +19 10 56.6730 2.46 1.18 -0.05 -1.03 -1.68 K1.5IIIFe-0.5 2131 0
2 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
3 NAME V645 Cen b Pl 14 29 42.9451234609 -62 40 46.170818907           ~ 204 0
4 * alf Cen ** 14 39 29.71993 -60 49 55.9990   0.4 -0.1     G2V+K1V 816 0
5 * alf Cen B PM* 14 39 35.06311 -60 50 15.0992 2.89 2.21 1.33     K1V 894 1
6 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

    Equat.    Gal    SGal    Ecl

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2020.07.04-15:34:02

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