Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"low-mass stars"”.
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Magnetic braking in low-mass stars
Low-mass stars with masses below about 1.3 solar masses exhibit intriguing trends in the evolution of their spins. These stars also exist in tidally locked binaries with a white dwarf (WD) companion, the cataclysmic variables (CVs). Their orbital evolution is driven by angular momentum loss due to …
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Activity and kinematics of low mass stars
We present an analysis of the magnetic activity, photometry and kinematics of approximately 70000 M dwarfs from the Sloan digital Sky Survey (SDSS) Data Release 7. This new analysis explores the spatial distribution of these M dwarf properties as a function of vertical distance from the Galactic …
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Rotation Period Distributions and Light Curve Morphologies of Low Mass Stars and Young Associations
… is centered around the rotation periods of low-mass stars and association of young stars. Rotation periods are a link to the age of the star, as they lose angular momentum over time. To understand how this angular momentum evolves requires understanding the rotation period distributions of a …
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The environmental impact of high- and low-mass stars: from formation to main sequence
… two different physical phenomena associated with stars: (1) the interplay of magnetic fields and collapsing clouds, and (2) the effects of radiation from massive stars. We first compare polarization measurements of 52 Galactic star-forming regions with their locations in the Galaxy. In particular, …
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Understanding the Star -Forming Environment in Stellar Clusters
… clusters, especially for the formation of low-mass cluster members. Embedded, young, and intermediate-mass stellar clusters around Herbig Ae/Be stars are sampled. Mid- and near-infrared observations identifying young stars and millimeter interferometric observations probing dense molecular …
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The Galactic Starburst Region NGC 3603 : exciting new insights on the formation of high mass stars
… is addressed by the question "How do high mass stars form?". While most details related to the formation and early evolution of low mass stars are quite well understood today, the basic processes leading to the formation of high mass stars still remain a mystery. There is no doubt that low …
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Development of an H-Alpha Index for the Detection of PMS Candidates in Young Open Clusters
<p>One phase of formation of medium- and low-mass stars is the optically visible phase known as the pre-main-sequence or PMS phase. In order to further the understanding of this phase, more of these PMS objects need to be identified and classified. Previous techniques have used photometry to …
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MINERVA-RED: A TELESCOPE DEDICATED TO THE DISCOVERY OF NEARBY PLANETS
… to detect exoplanets, planets orbiting other stars in the Milky Way. Today, thousands of these exoplanets are known, many detected through the subtle acceleration of a host star imparted by its orbiting planet(s). As the measurement techniques that are used to detect exoplanets through these …
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The Importance of Photoevaporation in the Evolution of Protoplanetary Discs
… of the star formation process - found around stars in the first few million years of their life. Photoevaporation, whereby high-energy radiation from the central star heats disc material causing it to flow away in a wind, is one process thought to contribute to their ultimate dispersal. …
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Protoplanetary discs across the stellar mass range
… with modelling protoplanetary discs around stars from different ends of the stellar mass range. In Chapters 1 and 2, I give an introduction to the field of protoplanetary discs, both from an observational and a modelling point of view, and describe the radiative transfer methods I have …
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The properties of transiting exoplanets
… the M1 dwarf K2-133. I later conducted a follow-up study on the K2-133 system, where I further constrained the stellar and planetary properties using the Gaia DR2 parallax distance, and WHT/LIRIS NIR spectra. I also statistically validated the planet candidate (planet e) – a fourth …
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Hydrogen-deficient central stars of planetary nebulae
Central stars of planetary nebulae are low-mass stars on the brink of their final evolution towards white dwarfs. Because of their surface temperature of above 25,000 K their UV radiation ionizes the surrounding material, which was ejected in an earlier phase of their evolution. Such fluorescent …
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A theoretical study of stellart pulsations in young brown dwarfs
This thesis reports the results of a twofold study on the recently proposed phenomenon of ‘stellar pulsations’ in young brown dwarfs by the seminal study of Palla and Baraffe (2005) (PB05, thereafter). The PB05 study presents results of a non-adiabatic linear stability analysis showing that young …
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A COMPARISON OF STAR FORMATION WITHIN THE GALACTIC CENTRE AND GALACTIC DISC
Stars are of fundamental importance to the entire field of astronomy. The conversion of elements and the distribution of energy throughout the lifetime of stars drives the evolution of the Universe. Despite this, we do not have a unified understanding of the formation process for all stars. This …