Detections of stellar coronal mass ejections (CMEs) are still rare.
Observations of strong Balmer line asymmetries during flare events have been
interpreted as being caused by CMEs. Here, we aim to estimate the maximum
possible Balmer line fluxes expected from CMEs to infer their detectability in
spectroscopic observations. Moreover, we use these results together with a
model of intrinsic CME rates to infer the potentially observable CME rates for
stars of different spectral types under various observing conditions, as well
as the minimum required observing time to detect stellar CMEs in Balmer lines.
We find that generally CME detection is favored for mid- to late-type M dwarfs,
as they require the lowest signal-to-noise ratio for CME detection, and the
fraction of observable-to-intrinsic CMEs is largest. They may require, however,
longer observing times than stars of earlier spectral types at the same
activity level, as their predicted intrinsic CME rates are lower. CME
detections are generally favored for stars close to the saturation regime,
because they are expected to have the highest intrinsic rates; the predicted
minimum observing time to detect CMEs on just moderately active stars is
already >100 h. By comparison with spectroscopic data sets including detections
as well as non-detections of CMEs, we find that our modeled maximum observable
CME rates are generally consistent with these observations on adopting
parameters within the ranges determined by observations of solar and stellar
prominences.
Description
Stellar coronal mass ejections II. Constraints from spectroscopic observations
%0 Generic
%1 odert2020stellar
%A Odert, P.
%A Leitzinger, M.
%A Guenther, E. W.
%A Heinzel, P.
%D 2020
%K activity
%T Stellar coronal mass ejections II. Constraints from spectroscopic
observations
%U http://arxiv.org/abs/2004.04063
%X Detections of stellar coronal mass ejections (CMEs) are still rare.
Observations of strong Balmer line asymmetries during flare events have been
interpreted as being caused by CMEs. Here, we aim to estimate the maximum
possible Balmer line fluxes expected from CMEs to infer their detectability in
spectroscopic observations. Moreover, we use these results together with a
model of intrinsic CME rates to infer the potentially observable CME rates for
stars of different spectral types under various observing conditions, as well
as the minimum required observing time to detect stellar CMEs in Balmer lines.
We find that generally CME detection is favored for mid- to late-type M dwarfs,
as they require the lowest signal-to-noise ratio for CME detection, and the
fraction of observable-to-intrinsic CMEs is largest. They may require, however,
longer observing times than stars of earlier spectral types at the same
activity level, as their predicted intrinsic CME rates are lower. CME
detections are generally favored for stars close to the saturation regime,
because they are expected to have the highest intrinsic rates; the predicted
minimum observing time to detect CMEs on just moderately active stars is
already >100 h. By comparison with spectroscopic data sets including detections
as well as non-detections of CMEs, we find that our modeled maximum observable
CME rates are generally consistent with these observations on adopting
parameters within the ranges determined by observations of solar and stellar
prominences.
@misc{odert2020stellar,
abstract = {Detections of stellar coronal mass ejections (CMEs) are still rare.
Observations of strong Balmer line asymmetries during flare events have been
interpreted as being caused by CMEs. Here, we aim to estimate the maximum
possible Balmer line fluxes expected from CMEs to infer their detectability in
spectroscopic observations. Moreover, we use these results together with a
model of intrinsic CME rates to infer the potentially observable CME rates for
stars of different spectral types under various observing conditions, as well
as the minimum required observing time to detect stellar CMEs in Balmer lines.
We find that generally CME detection is favored for mid- to late-type M dwarfs,
as they require the lowest signal-to-noise ratio for CME detection, and the
fraction of observable-to-intrinsic CMEs is largest. They may require, however,
longer observing times than stars of earlier spectral types at the same
activity level, as their predicted intrinsic CME rates are lower. CME
detections are generally favored for stars close to the saturation regime,
because they are expected to have the highest intrinsic rates; the predicted
minimum observing time to detect CMEs on just moderately active stars is
already >100 h. By comparison with spectroscopic data sets including detections
as well as non-detections of CMEs, we find that our modeled maximum observable
CME rates are generally consistent with these observations on adopting
parameters within the ranges determined by observations of solar and stellar
prominences.},
added-at = {2020-04-09T16:27:51.000+0200},
author = {Odert, P. and Leitzinger, M. and Guenther, E. W. and Heinzel, P.},
biburl = {https://www.bibsonomy.org/bibtex/2843b5c26e721648b396d8d2200e602fe/superjenwinters},
description = {Stellar coronal mass ejections II. Constraints from spectroscopic observations},
interhash = {037445e2d345959a2e1f067e939395d2},
intrahash = {843b5c26e721648b396d8d2200e602fe},
keywords = {activity},
note = {cite arxiv:2004.04063Comment: 35 pages, 11 figures, 6 tables; MNRAS, accepted},
timestamp = {2020-04-09T16:27:51.000+0200},
title = {Stellar coronal mass ejections II. Constraints from spectroscopic
observations},
url = {http://arxiv.org/abs/2004.04063},
year = 2020
}