High-resolution H-alpha observations of M dwarf stars Implications for stellar dynamo models and stellar kinematic properties at faint magnitudes

As for solar flares, one of the most physically revealing types of data for M-dwarf flares are high-resolution, time-resolved spectra. Due to the intrinsically faint nature of the M-dwarf stars, spectroscopic data has tended to be of low spectral (˜ 5 Ǻ) and temporal (˜ 5 min) resolution. However, with the development of image intensified spectrographs and fast, efficient digital detectors, the last several years have seen the successful acquisition of both high time and spectral resolution M-dwarf flare spectra. Recent programs have also been successfully conducted using the International Ultraviolet Explorer (IUE) satellite to obtain UV and EUV spectra of M-dwarf flares. These data reveal that dwarf M star flares are remarkably similar to solar flares in all aspects of their spectroscopic phenomenology.

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Magnetic fields in M dwarf stars from high-resolution infrared spectra

10.1063/1.3099081 ◽

2009 ◽

Cited By ~ 5

Author(s):

O. Kochukhov ◽

U. Heiter ◽

N. Piskunov ◽

N. Ryde ◽

B. Gustafsson ◽

...

Keyword(s):

High Resolution ◽

Magnetic Fields ◽

Infrared Spectra ◽

Dwarf Stars ◽

M Dwarf Stars ◽

M Dwarf

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The M dwarf problem: Fe and Ti abundances in a volume-limited sample of M dwarf stars

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa878 ◽

2020 ◽

Vol 494 (2) ◽

pp. 2718-2726 ◽

Cited By ~ 1

Author(s):

Vincent M Woolf ◽

George Wallerstein

Keyword(s):

High Resolution ◽

Galactic Chemical Evolution ◽

M Dwarfs ◽

Limited Sample ◽

Dwarf Stars ◽

Box Models ◽

Low Metallicity ◽

Celestial Equator ◽

M Dwarf Stars ◽

M Dwarf

ABSTRACT We report iron and titanium abundance measurements from high-resolution spectra in a volume-limited sample of 106 M0 and M0.5 dwarf stars. The sample includes stars north of the celestial equator and closer than 29 parsecs. The results imply that there is an M dwarf problem similar to the previously known G dwarf problem, in that the fraction of low-metallicity M dwarfs is not large enough to fit simple closed-box models of Galactic chemical evolution. This volume-limited sample avoids many of the statistical uncertainties present in a previous study using a brightness-limited sample of M dwarf stars.

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HADES RV programme with HARPS-N at TNG

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039478 ◽

2020 ◽

Vol 644 ◽

pp. A68

Author(s):

J. Maldonado ◽

G. Micela ◽

M. Baratella ◽

V. D’Orazi ◽

L. Affer ◽

...

Keyword(s):

High Resolution ◽

Stellar Mass ◽

M Dwarfs ◽

Dwarf Stars ◽

Large Sample ◽

Abundance Trends ◽

Low Mass ◽

M Dwarf Stars ◽

First Time ◽

M Dwarf

Context. Most of our current knowledge on planet formation is still based on the analysis of main sequence, solar-type stars. Conversely, detailed chemical studies of large samples of M dwarfs hosting planets are still missing. Aims. Correlations exist between the presence of different types of planets around FGK stars and metallicity, individual chemical abundance, and stellar mass. We aim to test whether or not these correlations still hold for the less-massive M dwarf stars. Methods to determine stellar abundances of M dwarfs from high-resolution optical spectra in a consistent way are still missing. The present work is a first attempt to fill this gap. Methods. We analyse a large sample of M dwarfs with and without known planetary companions in a coherent and homogeneous way. We develop for the first time a methodology to determine stellar abundances of elements other than iron for M dwarf stars from high-resolution optical spectra. Our methodology is based on the use of a principal component analysis and sparse Bayesian methods. We made use of a set of M dwarfs orbiting around an FGK primary with known abundances to train our methods. We applied our methods to derive stellar metalliticies and abundances of a large sample of M dwarfs observed within the framework of current radial-velocity surveys. We then used a sample of nearby FGK stars to cross-validate our technique by comparing the derived abundance trends in the M dwarf sample with those found on the FGK stars. Results. The metallicity distribution of the different subsamples reveals a correlation between the metallicities of M dwarfs and their probability of hosting giant planets. We also find a correlation between this latter probability and stellar mass. M dwarfs hosting low-mass planets do not seem to follow the so-called planet–metallicity correlation. We also find that the frequency of low-mass planets does not depend on the mass of the stellar host. These results appear to be in agreement with those of previous works. However, we note that for giant-planet hosts our metallicities predict a weaker planet–host metallicity correlation but a stronger mass-dependency than corresponding values derived from photometric results. We show for the first time that there seems to be no differences between M dwarfs with and without known planets in terms of their abundance distributions of elements different from iron. Conclusions. Our data show that low-mass stars with planets follow the same metallicity, mass, and abundance trends as their FGK counterparts, which are usually explained within the framework of core-accretion models.

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High resolution profiles of chromospheric lines in M dwarf stars

The Astrophysical Journal Supplement Series ◽

10.1086/190741 ◽

1981 ◽

Vol 46 ◽

pp. 159 ◽

Cited By ~ 17

Author(s):

S. P. Worden ◽

T. J. Schneeberger ◽

M. S. Giampapa

Keyword(s):

High Resolution ◽

Dwarf Stars ◽

M Dwarf Stars ◽

M Dwarf

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An Astrobiological Experiment to Explore the Habitability of Tidally Locked M-Dwarf Planets

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313012817 ◽

2012 ◽

Vol 8 (S293) ◽

pp. 192-196

Author(s):

Daniel Angerhausen ◽

Haley Sapers ◽

Eugenio Simoncini ◽

Stefanie Lutz ◽

Marcelo da Rosa Alexandre ◽

...

Keyword(s):

Academic Research ◽

Environmental Parameters ◽

Climate Simulation ◽

Habitable Zone ◽

Dwarf Stars ◽

Dwarf Planets ◽

Late Type Star ◽

M Dwarf Stars ◽

M Dwarf ◽

Simulation Chamber

AbstractWe present a summary of a three-year academic research proposal drafted during the Sao Paulo Advanced School of Astrobiology (SPASA) to prepare for upcoming observations of tidally locked planets orbiting M-dwarf stars. The primary experimental goal of the suggested research is to expose extremophiles from analogue environments to a modified space simulation chamber reproducing the environmental parameters of a tidally locked planet in the habitable zone of a late-type star. Here we focus on a description of the astronomical analysis used to define the parameters for this climate simulation.

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Coronal Structure in M Dwarf Stars

Magnetodynamic Phenomena in the Solar Atmosphere ◽

10.1007/978-94-009-0315-9_16 ◽

1996 ◽

pp. 81-82

Author(s):

M. S. Giampapa ◽

R. Rosner ◽

V. Kashyap ◽

T. A. Fleming ◽

J. H. M. M. Schmitt ◽

...

Keyword(s):

Coronal Structure ◽

Dwarf Stars ◽

M Dwarf Stars ◽

M Dwarf

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The habitability of stagnant-lid Earths around dwarf stars

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834658 ◽

2019 ◽

Vol 625 ◽

pp. A12 ◽

Cited By ~ 8

Author(s):

Mareike Godolt ◽

Nicola Tosi ◽

Barbara Stracke ◽

John Lee Grenfell ◽

Thomas Ruedas ◽

...

Keyword(s):

Water Loss ◽

Main Sequence ◽

Extrasolar Planets ◽

Water Reservoir ◽

Habitable Zone ◽

High Luminosity ◽

Dwarf Stars ◽

Surface Conditions ◽

M Dwarf Stars ◽

M Dwarf

Context. The habitability of a planet depends on various factors, such as the delivery of water during its formation, the co-evolution of the interior and the atmosphere, and the stellar irradiation which changes in time. Aims. Since an unknown number of rocky extrasolar planets may operate in a one-plate convective regime, i.e. without plate tectonics, our aim is to understand the conditions under which planets in such a stagnant-lid regime may support habitable surface conditions. Understanding the interaction of the planetary interior and outgassing of volatiles in combination with the evolution of the host star is crucial to determining the potential habitability. M-dwarf stars in particular possess a high-luminosity pre-main sequence phase that endangers the habitability of planets around them via water loss. We therefore explore the potential of secondary outgassing from the planetary interior to rebuild a water reservoir allowing for habitability at a later stage. Methods. We compute the boundaries of the habitable zone around M-, K-, G-, and F-dwarf stars using a 1D cloud-free radiative-convective climate model accounting for the outgassing history of CO2 and H2O from an interior evolution and outgassing model for different interior compositions and stellar luminosity evolutions. Results. The outer edge of the habitable zone strongly depends on the amount of CO2 outgassed from the interior, while the inner edge is mainly determined via the stellar irradiation, as soon as a sufficiently large water reservoir has been outgassed. A build-up of a secondary surface and atmospheric water reservoir for planets around M-dwarf stars is possible even after severe water loss during the high-luminosity pre-main sequence phase as long as some water has been retained within the mantle. For small mantle water reservoirs, between 62 and 125 ppm, a time delay in outgassing from the interior permits such a secondary water reservoir build-up especially for early and mid-M dwarfs because their pre-main sequence lifetimes are shorter than the outgassing timescale. Conclusions. We show that Earth-like stagnant-lid planets allow for habitable surface conditions within a continuous habitable zone that is dependent on interior composition. Secondary outgassing from the interior may allow for habitability of planets around M-dwarf stars after severe water loss during the high-luminosity pre-main sequence phase by rebuilding a surface water reservoir.

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