Circumstellar envelopes of intermediate mass young stars

• Grant number: 08/01533-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2008
• End date: August 31, 2012
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Jane Cristina Gregorio-Hetem
• Grantee: Rodrigo Georgetti Vieira
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 05/00397-1 - Chemical evolution and galactic and extragalactic stellar populations by spectroscopy and imaging, AP.TEM

Abstract

Herbig Ae/Be stars are classified in groups according to the slope of their spectral energy distribution (SED) in the infrared region. The steeper is this slope, the greater are the infrared excesses observed and the amount of circumstellar material associated to the object. Some works relate this classification to the evolutive stage of the object, where the most embeded objects (those with the larger circumstellar structures) are expected to be found in the first stages of pre-main sequence evolution. In the present work, we will select a sample of objects classified as Herbig Ae/Be stars, which probably have spherical envelopes made of gas and dust and other characteristics typically found in less evolved objects. We will study such envelopes following the two main approachs: (i) modelling of the dust-gas surrounding, in order to reproduce the physical conditions related to the radaitive transfer processes and the particle dynamics; and (ii) sensible observations of high spatial resolution, to obtain direct images in sub-millimetric wavelengths. These observations will allow the measurement of the circumstellar parameters, such as the mass and the size of the envelope, which will be confronted to those calculated by the model. The observational data will be obtained in collaboration with the group of Dr. P. André, the Principal Investigator of ArTeMiS project.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

VIEIRA, R. G.; GREGORIO-HETEM, J.; HETEM, JR., A.; STASINSKA, G.; SZCZERBA, R.. Distinguishing post-AGB impostors in a sample of pre-main sequence stars. Astronomy & Astrophysics, v. 526, FEB 2011. (05/00397-1, 08/01533-4)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

VIEIRA, Rodrigo Georgetti. Circumstellar envelopes of intermediate mass young stars. 2012. Doctoral Thesis - Universidade de São Paulo (USP). Instituto Astronômico e Geofísico (IAG/SBD) São Paulo.