Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- I Searches in Clusters, Stellar Associations and the Field
- II Spectroscopic Properties, Fundamental Parameters and Modelling
- Properties of M Dwarfs in Clusters and the Field
- Spectroscopy of Very Low Mass Stars and Brown Dwarfs in Young Clusters
- High Resolution Spectra of L Type Stars and Brown Dwarfs
- Modelling Very Low Mass Stars and Brown Dwarfs Atmospheres: The Importance of Dust Formation
- Dust in Very Cool Dwarfs
- On the Interpretation of the Optical Spectra of Very Cool Dwarfs
- Absolute Dimensions for M Type Dwarfs
- Theory of Low Mass Stars and Brown Dwarfs: Success and Remaining Uncertainties
- III Convection, Rotation and Activity
- Author index
Absolute Dimensions for M Type Dwarfs
from II - Spectroscopic Properties, Fundamental Parameters and Modelling
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Preface
- Acknowledgements
- I Searches in Clusters, Stellar Associations and the Field
- II Spectroscopic Properties, Fundamental Parameters and Modelling
- Properties of M Dwarfs in Clusters and the Field
- Spectroscopy of Very Low Mass Stars and Brown Dwarfs in Young Clusters
- High Resolution Spectra of L Type Stars and Brown Dwarfs
- Modelling Very Low Mass Stars and Brown Dwarfs Atmospheres: The Importance of Dust Formation
- Dust in Very Cool Dwarfs
- On the Interpretation of the Optical Spectra of Very Cool Dwarfs
- Absolute Dimensions for M Type Dwarfs
- Theory of Low Mass Stars and Brown Dwarfs: Success and Remaining Uncertainties
- III Convection, Rotation and Activity
- Author index
Summary
M-type stars define the lowest end of the main sequence and the connection between normal stars and brown dwarfs. For these reasons, the determination of accurate absolute dimensions in very low mass stars is a fundamental astrophysical problem. Moreover, they are a numerous population in our galaxy, provide limit conditions for core hydrogen burning, and allow the test of different treatments of convective energy transport.
Absolute dimensions for the comparison of empirical data with theoretical models are generally reduced to mass, radius, and temperature. The estimation of each of them as a function of colour indices, by means of either direct determinations or the use of calibration curves, is reviewed together with the available information derived from the study of well-detached double-lined eclipsing binaries.
Introduction
Red dwarfs are among the least massive stellar objects in the Universe. Among them, M-type stars are in the mass range from around 0.1 to 0.5 solar masses. At lower values we only find brown dwarfs or non-stellar planetary bodies. Nevertheless, low-mass stars are probably the most common type in our Galaxy, with a high potential influence in the definition of its mass function. They also provide the connection between objects with radiation generated through nuclear reactions and those which are not able to do so because of insuficiently high internal temperatures. From the structural point of view, M-type stars are very important because they are dominated by convective energy transport, and the treatment of convection is still one of the least known parts of the theory of stellar structure.
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- Very Low-Mass Stars and Brown Dwarfs , pp. 175 - 185Publisher: Cambridge University PressPrint publication year: 2000