Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275429
Title: Coronal emission from late-type stars : a ROSAT and XMM view
Author: Briggs, Kevin
Awarding Body: University of Leicester
Current Institution: University of Leicester
Date of Award: 2002
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Abstract:
In Chapter I, I introduce the framework of observational and theoretical evidence that has been constructed to understand the vast range of X-ray characteristics exhibited by late-type stars on the basis of the magnetic dynamo that is thought to power the Sun's own modest X-ray activity, and describe the spectral analysis techniques and X-ray instruments used in this work. In Chapter 2 I present a catalogue-based classification of X-ray sources detected in the ROSAT PSPC Galactic Plane Survey in the Third Quadrant (3QGPS) and use the results to infer a denser spatial distribution of young, X-ray active stars in the local Galaxy than has been traditionally assumed. In Chapter 3 I exploit the high coronal activity of young stars to search for unrecognised members of the Hyades-age open clusters NGC 6633 and IC 4756 in deep ROSAT HRI images, and make a novel comparison of the X-ray activity levels of these clusters with that of the Hyades. In Chapter 4 I explore the X-ray emission from very low mass stars in an XMM-Newton EPIC pointing in the Pleides, finding marginal support for a decline in X-ray activity for stars with spectral types later than " M4 that may be a signature of the changeover to a non-solar-like dynamo in fully-convective stars. I also undertake spectral and variability studies of the X-ray-bright members in the field, and present evidence that the detection of early-type stars in the cluster are fully consistent with emission from late-type companions. In Chapter 5 I perform a time-resolved spectroscopic study of the nearby active K0 star AB Dor using the XMM-Newton EPIC pn, with comparison to a study using the higher-resolution XMM-Newton RGS, investigating the temperature structure and elemental adundance changes during the course of a moderate flare.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.275429  DOI: Not available
Keywords: Astronomy Astronomy
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