MARC details
| 000 -LEADER |
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| fixed length control field |
03408nam a2200229Ia 4500 |
| 003 - CONTROL NUMBER IDENTIFIER |
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| control field |
IN-BaIIA |
| 005 - DATE AND TIME OF LATEST TRANSACTION |
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| control field |
20211110123209.0 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION |
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| fixed length control field |
211028s9999 xx 000 0 eng d |
| 040 ## - CATALOGING SOURCE |
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| Transcribing agency |
IIA Library |
| 080 ## - UNIVERSAL DECIMAL CLASSIFICATION NUMBER |
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| Universal Decimal Classification number |
043:524.3 |
| Item number |
SIV |
| 100 ## - MAIN ENTRY--PERSONAL NAME |
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| Personal name |
Sivarani, T. |
| 9 (RLIN) |
24330 |
| Relator term |
Author |
| 245 #6 - TITLE STATEMENT |
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| Title |
A and F stars with circumstellar dust. Ph. D. Thesis |
| Statement of responsibility, etc. |
T. Sivarani |
| Medium |
[Ph.D Thesis] |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. |
|---|
| Place of publication, distribution, etc. |
Bangalore |
| Name of publisher, distributor, etc. |
Indian Institute of Astrophysics |
| Date of publication, distribution, etc. |
2000 |
| 300 ## - PHYSICAL DESCRIPTION |
|---|
| Extent |
150p. |
| 502 ## - DISSERTATION NOTE |
|---|
| Degree type |
Doctor of Philosophy |
| Name of granting institution |
Indian Institute of Astrophysics, Bangalore |
| Year degree granted |
2000 |
| 520 ## - SUMMARY, ETC. |
|---|
| Summary, etc. |
Cirumstellar dust plays an important role in stellar evolution. From the analysis<br/>of IRAS (Infra Red Astronomial Satellite) data of several A and F stars whi<br/>h are young (pre-mainsequene) and evolved (AsymptotiGiant Branh (AGB) and post-<br/>AGB), showed the presene ofirumstellar dust shells.theirumstellar dust around starshanges the spetral energy distribution aswell as the spetral line features of the photosphere. Some stars show shell lines. Insomeases theirumstellar dust plays a major role in understanding the peuliarhemialomposition of the photosphere. Studying the<br/>irumstellar environment ofthese stars and the inuene ofirumstellar matter on the photospheri<br/>spetrumhelps us to understand the pre-mainsequene and post-mainsequen<br/>e evolution.Pre-mainsequene stars haveirumstellar envelopes as a natural proess of starformation. But as it reahes the mainsequene stage only some stars retain theirir<br/>umstellar disk. These starsould probably be having a planetary system. Inonne<br/>tion to the planetary formation, it is interesting to study these stars whihhaveirumstellar dust. Reently even the evolved stars whih is a proto-planetary nebula (Red Retangle Nebula (Jura and Turner, 1998)) seem to show eviden<br/>e ofplanetary formation. After the disovery of planets around pulsars, this is the rsteviden<br/>e of planets around a post-mainsequene star. A-F stars have the most simple<br/>atmosphereompared to any other spetral type. Still there are only a few normal A<br/>stars Bidelman says that "He has never seen any normal A-star". boo stars are one<br/>of thehemially puliar stars seen in the mainsequene in the spe<br/>tral range A-F.These stars seem to have got the peuliaromposition as a result of the inueneofirumstellar dust. They show depletion in metals and show normal C,N,O,S andZn abundanes. Many of the boo stars show IR (Infra Red) ex<br/>ess due to dust.Some of the metal poor post-AGB stars also show similarharateristi<br/>s like the <br/>boo stars. And these post-AGB stars are asso<br/>iated with<br/>ir<br/>umstellar dust shells.<br/>So it is very essential to know that the metal poor<br/>hara<br/>ter is due to the population<br/>II nature of the obje<br/>t or due to fra<br/>tionation or both.The pre-mainsequene stars and post-AGB stars have detahed dust shells. Someof the pre-mainsequene stars have similar IRASolors like that of Proto Plane-tary Nebulae (PPN). In order to distinguish the evolutionary stage of the various<br/>type of stars withirumstellar dust shells and to understand the physial proesses(mass-loss, shoks, mixing, and frationation), we need toarry out high resolutionspetrosopistudy. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
stars |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
|---|
| Topical term or geographic name entry element |
thesis |
| 9 (RLIN) |
18401 |
| 700 ## - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
M. Parthasarathy |
| Relator term |
Supervisor |
| 9 (RLIN) |
48857 |
| 856 ## - ELECTRONIC LOCATION AND ACCESS |
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| Uniform Resource Identifier |
<a href="http://prints.iiap.res.in/handle/2248/828">http://prints.iiap.res.in/handle/2248/828</a> |
| Link text |
Click Here to Access eThesis |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) |
|---|
| Koha item type |
Thesis & Dissertations |
| Source of classification or shelving scheme |
Universal Decimal Classification |
