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Mt. Suhora Survey - Searching for Pulsating M Dwarfs. III

Baran A. S., Winiarski M., Siwak M., Fox-Machado L., Kozieł-Wierzbowska D., Krzesinski J., Dróżdz M., Winans A.

Acta Astronomica

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2013

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Vol. 63, No. 1

41--52

EN

We present our final report on the search for pulsating M dwarfs. We used moderate (<1 m) ground-based telescopes. Our detection was limited to 1 ppt, which is roughly 0.1% of flux variation. We employed both the Fourier technique and Phase Dispersion Minimization (PDM) method. Our data analyses revealed no detection of pulsations in M dwarfs down to the above amplitude level. The results of our survey cannot reject or confirm the theoretical calculations suggesting the M dwarfs can pulsate, however, if the pulsations exist in these stars their amplitudes must be lower than 1 ppt. As a by-product of our search we found several new variable stars, including pulsating stars, binary systems and flare stars.

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Mt. Suhora Survey - Searching for Pulsating M Dwarfs. II

Krzesinski J., Baran A. S., Winiarski M., Fox-Machado L., Dróżdż M., Siwak M., Kozieł-Wierzbowska D.

Acta Astronomica

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2012

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Vol. 62, No. 2

201--212

EN

We present our report on the second part of our ongoing project which aims at finding stellar pulsations in early type M dwarfs. Our search is based on time-series photometric data acquired mainly at Mt. Suhora Observatory, though, several stars have been observed from other sites. Data of 49 M dwarfs are included in this paper. We analyzed the data by means of the Fourier technique as well as Phase Dispersion Minimization method. We still cannot confirm any pulsating M dwarf at the model-predicted period of 23-40 min. In addition to our main goal we searched for flare activities, planetary transits and other types of brightness changes. We did find several new variable stars, including pulsating stars, binary systems and flare stars, however, only flaring M dwarfs are presented in this paper.

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Mt. Suhora Survey - Searching for Pulsating M Dwarfs in Kepler Public Dataset

Baran A. S., Fox-Machado L., Lykke J., Nielsen M., Telting J. H.

Acta Astronomica

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2011

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Vol. 61, No. 4

325--343

EN

We present our analysis of Kepler short cadence public data to search for stellar pulsations in M dwarfs. Theoretical calculations predict that these stars may suffer from a fundamental radial mode driven by the nuclear ε mechanism. First results published thus far show no significant signal around the expected frequency of 36 c/d down to 1 ppt (parts per thousand). In this paper we include new results obtained from a sample of 86 stars, although a real number of M dwarfs after spectral classification turned out to be small. Unluckily, we have not detected any significant signal typically down to 1-10 ppm (parts per million) in M dwarfs and since the sample of these stars consists of 6 objects only, we cannot make any strong conclusion if the ε mechanism drives perturbation in radius to propagate to a detectable amplitude at the surface. As a by-product of our work we provide a spectral classification of 86 Kepler objects, along with their variability and thus far unknown artifacts residing in Kepler photometry.

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Mt. Suhora Survey - Searching for Pulsating M Dwarfs. I

Baran A. S., Winiarski M., Krzesiński J., Fox-Machado L., Kawaler S. D., Dróżdż M., Faltenbacher A., Thompson M. A., Reed M. D.

Acta Astronomica

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2011

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Vol. 61, No. 1

37--58

EN

We present the first results of our M dwarf survey in search for stellar pulsation in low mass main sequence stars. Theoretical calculations predict that ε mechanism might drive a fundamental radial mode in these stars and therefore pulsations could be observed photometrically. Although M dwarfs are known for their flare and spot activity they have not yet been the subject of dedicated time-series surveys for pulsation. In this work we include the light curves and amplitude spectra of 46 M dwarfs, which have been observed during the first two years of our survey. We did not detect any pulsations yet. As a by-product of our search, we describe the light curves of some flare M dwarfs. The survey will last for two more years and during that period more than a hundred of M0-M4 type main sequence stars will be observed.