J/A+A/637/A13 AD Leo high resolution spectra (Muheki+, 2020)
High resolution spectroscopy of flares and CMEs on AD Leonis.
Muheki P., Guenther E..W., Mutabazi T., Jurua E.
<Astron. Astrophys. 637, A13 (2020)>
=2020A&A...637A..13M 2020A&A...637A..13M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, M-type ; Spectra, optical
Keywords: techniques: spectroscopic - Sun: activity - stars: flare -
stars: late-type - stars: individual: AD Leo
Abstract:
Flares and coronal mass ejections (CMEs) are important for the
evolution of the atmospheres of planets and their potential
habitability, particularly for planets orbiting M stars at a distance
<0.4AU. Detections of CMEs on these stars have been sparse, and
previous studies have therefore modelled their occurrence frequency by
scaling up solar relations. However, because the topology and strength
of the magnetic fields on M stars is different from that of the Sun,
it is not obvious that this approach works well.
We used a large number of high-resolution spectra to study flares,
CMEs, and their dynamics of the active M dwarf star AD Leo. The
results can then be used as reference for other M dwarfs.
We obtained more than 2000 high-resolution spectra (R∼35000) of the
highly active M dwarf AD Leo, which is viewed nearly pole on. Using
these data, we studied the behaviour of the spectral lines Hα,
Hβ, and HeI 5876 in detail and investigated asymmetric features
that might be Doppler signatures of CMEs.
We detected numerous flares. The largest flare emitted 8.32x1031erg
in Hβ and 2.12x1032erg in Hα. Although the spectral lines
in this and other events showed a significant blue asymmetry, the
velocities associated with it are far below the escape velocity.
Although AD Leo shows a high level of flare activity, the number of
CMEs is relatively low. It is thus not appropriate to use the same
flare-to-CME relation for M dwarfs as for the Sun.
Description:
The 2-m Alfred Jensch telescope of the Thueringer Landessternwarte
Tautenburg, which is equipped with an echelle spectrograph (R∼35000)
and a 2" slit was used. The spectra cover the wavelength region from
4536 to 7592Å. The observations were done between November 2016 to
February 2019. 2009 spectra were obtained in 57 nights of observation.
Objects:
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RA (2000) DE Designation(s)
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10 19 36.28 +19 52 12.0 AD Leo = BD+20 2465
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 106 2002 List of spectra files
fits/* . 2002 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Simbad right ascension (J2000)
4- 5 I2 min RAm Simbad right ascension (J2000)
7- 11 F5.2 s RAs Simbad right ascension (J2000)
12 A1 --- DE- Simbad declination sign (J2000)
13- 14 I2 deg DEd Simbad declination (J2000)
16- 17 I2 arcmin DEm Simbad declination (J2000)
19- 22 F4.1 arcsec DEs Simbad declination (J2000)
24- 27 I4 --- Nx Number of pixels along X-axis
29- 30 I2 --- Ny Number of pixels along Y-axis
32- 50 A19 "datime" Obs.date Observation date
52- 54 I3 Kibyte size Size of FITS file
56- 79 A24 --- FileName Name of FITS file, in subdirectory fits
81-106 A26 --- Title Title of the FITS file
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Acknowledgements:
Priscilla Muheki, pmuheki(at)must.ac.ug
(End) Patricia Vannier [CDS] 31-Mar-2020