Tracers of Chromospheric Structure I: Observations of Ca II K and H alpha in M Dwarfs

Abstract

We report on our observing program to capture simultaneous spectra of Ca II and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate the chromospheric temperature structure required to produce these lines at the observed levels. We find a strong positive correlation between instantaneous measurements of Ca II K and the Balmer lines in active stars, although these lines may not be positively correlated in time-resolved measurements. The relationship between H alpha and Ca II K remains ambiguous for weak and intermediate activity stars, with H alpha absorption corresponding to a range of Ca II K emission. A similar relationship is also observed between Ca II K and the higher order Balmer lines. As our sample consists of a single spectral type, correlations between these important chromospheric tracers cannot be ascribed to continuum effects, as suggested by other authors. These data confirm prior non-simultaneous observations of the H alpha line behavior with increasing activity, showing an initial increase in the H alpha absorption with increasing Ca II K emission, prior to H alpha filling in and eventually becoming a pure emission line in the most active stars. We also compare our optical measurements with archival UV and X-ray measurements, finding a positive correlation between the chromospheric and coronal emission for both high and intermediate activity stars. We compare our results with previous determinations of the active fraction of low mass stars, and discuss them in the context of surface inhomogeneity. Lastly, we discuss the application of these data as empirical constraints on new static models of quiescent M dwarf atmospheres.

arXiv comment25 pages, 16 figures; accepted for publication in the Astronomical Journal

References in corpus (13)

• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• Constraining the Age-Activity Relation for Cool Stars: The SDSS DR5 Low-Mass Star Spectroscopic Sample
• Chromospheric CaII Emission in Nearby F, G, K, and M stars
• The Palomar/MSU Nearby Star Spectroscopic Survey III: Chromospheric Activity, M-dwarf Ages and the Local Star Formation History
• Simulations of dynamo action in fully convective stars
• Spectroscopic Properties of Cool Stars in the SDSS: An Analysis of Magnetic Activity and a Search for Subdwarfs
• A solar surface dynamo
• Fluxes in Hαand Ca II H and K for a sample of Southern stars
• X-ray properties of active M dwarfs as observed by XMM-Newton
• Dynamics of the Solar Magnetic Network. II. Heating the Magnetized Chromosphere
• Ca II H and K Chromospheric Emission Lines in Late K and M Dwarfs
• Characterizing the Near-UV Environment of M Dwarfs
• Convective Dynamos and the Minimum X-ray Flux in Main Sequence Stars

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