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.
Results
Showing 1 to 10 of 10 for “"Circumstellar disk"”.
-
Optical and X-ray studies of Be/X-ray binaries in the Small Magellanic Cloud
… interactions taking place between the Be star’s circumstellar disk and the neutron star are being revealed. These data are providing the building blocks that may help explain the physical processes that produce the circumstellar disk. In addition, the optical counterpart to SXP15.3 is discussed …
-
High resolution studies of early type emission line stars
… of the systems suggest that they form via disk fragmentation. To test this conclusion, disk and binary position angles are compared to a model in which the circumstellar disk and binary orbits are co-planar. The data are consistent with the coplanar model and thus with the scenario of disk …
-
The Inner Gaseous Disks Of Herbig Be Stars
… 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 …
-
Circumstellar environments around the youngest protostars: interferometric observations and modeling
… collapse inside their natal envelopes, and these circumstellar envelopes contain valuable information about the physical processes of star formation. In this thesis, both molecular lines and dust continuum are utilized to investigate the nature of the collapsing envelopes. In particular, I focus …
-
Optical spectroscopic studies of two star forming regions
… an initial mass function (IMF), investigate disk evolution, and determine the star-forming history. Optical spectroscopic surveys of an unbiased sample of candidate young stars have been completed. Optical images taken in different photometric bands were used to create color-magnitude …
-
Nitrogen Abundances in Early-Type Be Stars
… Sun, that are surrounded by a thin, equatorial disk of gas that produces emission lines in their optical and near-infrared spectra. Be stars are the most rapidly-rotating stellar population on the main sequence, where stars produce energy by core hydrogen burning. New, non-LTE line transfer …
-
Angular Momentum Evolution of Young Stars
… as a result of magnetic coupling to their circumstellar disk (``disk-locking''). The resulting locking period is about 8 days. My analysis further showed that ``disk-locking'' in NGC\,2264 or the ONC is important only for higher mass stars (M >= 0.3$\msun$). There is evidence that also the …
-
Binary Star Systems with Asymmetrically Heated Disks: Thermal Phase Curves for the Disk in Epsilon Aurigae
… that contains a warm F-star (~7750 K) and a circumstellar disk enshrouding a hidden companion, likely to be a hot B-star (>15,000 K). The eclipse itself lasts just over two years---thanks, in part, to the size of the disk---and occurs every 27.1-years. Its evolutionary status is still …
-
Observations of disks around the youngest protostars: Characterizing frequency, dust properties, and magnetic fields at the earliest times
Circumstellar disks are fundamental for accretion and angular momentum distribution during the early phases of star formation. Class 0 objects are the youngest protostars and most embedded in their natal envelopes, and circumstellar disks can form even at this earliest stage of star formation. …
-
Observations of protostellar systems across sub/millimeter wavelengths in nearby molecular clouds
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms