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Stars, Interstellar Medium and the Galaxy Commons™
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- Keyword
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- Astronomical Instrumentation (1)
- Atomic/Molecular Processes (1)
- Circumstellar Disks (1)
- Coherent Interactions (1)
- Emission Line stars (1)
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- Herbig Ae/Be stars (1)
- Infrared (1)
- Interstellar Medium (1)
- Magnetic fields (1)
- Maser (1)
- Modeling (1)
- Orion Molecular Cloud (1)
- Pre-main sequence stars (1)
- Spectrum Synthesis (1)
- Star formation (1)
- Stars: convection (1)
- Stars: individual (α Sco A) (1)
- Stars: oscillations (1)
- Stars: variables: general (1)
- Stellar Spectroscopy (1)
- Submillimetre (1)
- Superradiance (1)
- Techniques: radial velocities (1)
- Techniques: spectroscopic (1)
- UV (1)
Articles 1 - 5 of 5
Full-Text Articles in Stars, Interstellar Medium and the Galaxy
Dicke’S Superradiance In Astrophysics, Fereshteh Rajabi
Dicke’S Superradiance In Astrophysics, Fereshteh Rajabi
Electronic Thesis and Dissertation Repository
It is generally assumed that in the interstellar medium much of the emission emanating from atomic and molecular transitions within a radiating gas happen independently for each atom or molecule, but as was pointed out by R. H. Dicke in a seminal paper several decades ago this assumption does not apply in all conditions. As will be discussed in this thesis, and following Dicke’s original analysis, closely packed atoms/molecules can interact with their common electromagnetic field and radiate coherently through an effect he named superradiance. Superradiance is a cooperative quantum mechanical phenomenon characterized by high intensity, spatially compact, burst-like features …
The Inner Gaseous Disks Of Herbig Be Stars, Parshati Patel
The Inner Gaseous Disks Of Herbig Be Stars, Parshati Patel
Electronic Thesis and Dissertation Repository
Herbig Ae/Be stars are intermediate mass (~2 to 20Msun) pre-main sequence stars that inherit a circumstellar disk of dust and gas from their formation phase. The region of this disk closest to the star is entirely gaseous because dust evaporates at the high temperatures there, and this gaseous region is currently poorly understood. Using non-LTE circumstellar disk codes to model the optical and near-infrared spectra of five, early-type (B0Ve to B2Ve) Herbig Be stars obtained with the Canada-France-Hawaii telescope ESPaDOnS instrument, the density structure of each inner gaseous disks was determined and estimates of the disk masses and …
Stellar Spectroscopy: New Methods And Insights, Sanaz S. Golriz
Stellar Spectroscopy: New Methods And Insights, Sanaz S. Golriz
Electronic Thesis and Dissertation Repository
The study of the chemical evolution of stars is of crucial importance since they play a major role in the enrichment of the chemistry of the universe. Throughout their lifetime, stars undergo several processes that can alter their chemistry. Gradually, the nucleosynthesis products from the interior of the star are radiatively and convectively levitated and mixed with the upper layers of the atmosphere. In the later stages of their evolution, low to intermediate mass stars (0.8-8.0~M☉) eject a significant fraction of these nucleosynthesis products, resulting in a circumstellar envelope of gas and dust around the central star with a very …
Methods And Results Toward Measuring Magnetic Fields In Star-Forming Regions, Scott C. Jones
Methods And Results Toward Measuring Magnetic Fields In Star-Forming Regions, Scott C. Jones
Electronic Thesis and Dissertation Repository
Star formation is a fundamental process in the evolution of the cosmos. Yet given the abundance of stellar constituents, it remains prescient as to why the number of stars is not correspondingly large. If we cannot satisfactorily explain how stars are formed, then many further avenues of research are hindered. This thesis makes claims about one of the foremost theories as to the relative lack of stars, interstellar magnetic fields. These fields have been observationally verified on multiple scales. I will use the most direct method to probe magnetic fields in known star-forming regions, polarization, at millimetre/submillimetre wavelengths. In particular …
A Variability Study Of The Typical Red Supergiant Antares A, Teznie J D Pugh
A Variability Study Of The Typical Red Supergiant Antares A, Teznie J D Pugh
Electronic Thesis and Dissertation Repository
Red giants and red supergiants have long been known to be variable. In the last 40 years many of the features of this variability have been associated with large convective cells. Unfortunately, due to the long timescales of these variations they are not well studied, with the exception of the bright M-class supergiant Betelgeuse (α Orionis, M2 Iab). Betelgeuse has been well studied both observationally and theoretically, and has many features that are well described by models of convection. It was these studies of Betelgeuse that provided the main motivation for this thesis. We ask if the dramatic motions seen …