Schisano, Eugenio
(2010)
Characterizing circumstellar disk around young stars.
[Tesi di dottorato]
(Unpublished)
| Item Type: |
Tesi di dottorato
|
| Resource language: |
English |
| Title: |
Characterizing circumstellar disk around young stars |
| Creators: |
| Creators | Email |
|---|
| Schisano, Eugenio | eugdan@hotmail.it |
|
| Date: |
30 November 2010 |
| Number of Pages: |
120 |
| Institution: |
Università degli Studi di Napoli Federico II |
| Department: |
Scienze fisiche |
| Scuola di dottorato: |
Scienze fisiche |
| Dottorato: |
Fisica fondamentale ed applicata |
| Ciclo di dottorato: |
22 |
| Coordinatore del Corso di dottorato: |
| nome | email |
|---|
| Marrucci, Lorenzo | lorenzo.marrucci@na.infn.it |
|
| Tutor: |
| nome | email |
|---|
| Smaldone, Luigi Antonio | smaldone@na.infn.it | | Alcalà, Juan Manuel | alcala@na.astro.it | | Covino, Elvira | covino@na.astro.it |
|
| Date: |
30 November 2010 |
| Number of Pages: |
120 |
| Keywords: |
Circumstellar disks |
| Settori scientifico-disciplinari del MIUR: |
Area 02 - Scienze fisiche > FIS/05 - Astronomia e astrofisica |
[error in script]
[error in script]
| Date Deposited: |
10 Dec 2010 14:53 |
| Last Modified: |
30 Apr 2014 19:46 |
| URI: |
http://www.fedoa.unina.it/id/eprint/8443 |
| DOI: |
10.6092/UNINA/FEDOA/8443 |
Collection description
The circumstellar disks play a fundamental role in star and planet formation
process. Studies on circumstellar disks are generally carried on following two
viable approaches: "statistical" studies, where a large samples of sources
are measured to determine mean disk common properties, detailed study
on individual objects can shed the light on processes, like mass accretion,
central star irradiation or photoevaporation, that compete in defining the
shape and the lifetime of the disks, improving the theoretical models or,
hopefully, to directly catch a planet in the process of forming.
Although both approaches converge toward a general scenario, they are sensitive only the disk dust component, while recently there is a strong interest on the gas, since it constitutes most of the mass of the circumstellar disks, determining the dust dynamic and the settling process, and its dispersal timescales limit the formation of gas giant planets.
In this work I present a synoptic study carried on the young stellar object
TCha, belonging to the class of "transition" disks, peculiar systems where
very rapid evolution is ongoing. Such transitional disks are rare and, due to
their classification based on the shape of the spectral energy distribution, do
not represent an homogeneous class. For such reasons the characterization
of any further object is extremely important to understand if we are dealing
with a planetary system in formation.
On the other side, I carried on a systematic study on recent discovered diagnostic for the gaseous disk component. The fine structure infrared emission line of [Ne ii] at 12.8 m has been discovered in more than 70 object. This line is thought to be produced by X-ray irradiation of the warm protoplanetary disk atmospheres, however the observational correlation between [Ne ii]luminosities and measured X-ray luminosities shows a large scatter. Such spread limits the utility of this line as a probe of the gaseous phase of disks, as several authors have suggested pollution by outflows as a probable cause of the observed scatter. For the first time with this work it has been explored the possibility that the large variations in the observed [Ne ii] luminosity may be caused instead by different star-disk parameters.
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