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3 edition of The circumstellar environments of intermediate mass main sequence stars found in the catalog.

The circumstellar environments of intermediate mass main sequence stars

The circumstellar environments of intermediate mass main sequence stars

a final report

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  • 9 Currently reading

Published by National Aeronautics and Space Administration, For sale by the Clearinghouse for Federal Scientific and Technical Information in [Washington, DC, Springfield, Va .
Written in English

    Subjects:
  • Circumstellar matter.

  • Edition Notes

    StatementCarol Grady.
    SeriesNASA contractor report -- NASA CR-189311.
    ContributionsUnited States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15388154M

    Astronomers use stellar flux and the inverse-square law to extrapolate circumstellar habitable zone models created for the Solar System to other stars. For example, although the Solar System has a circumstellar habitable zone centered at AU from the Sun, a star with times the luminosity of the Sun would have a habitable zone centered at, or , the distance from the star. Dynamical Mass Measurements of Pre-Main-Sequence Stars: Fundamental Tests of the Physics of Young Stars (pp. –) R. D. Mathieu, I. Baraffe, M. Simon, K. G. Stassun, and R. White pdf ( K) Not Alone: Tracing the Origins of Very-Low-Mass Stars and Brown Dwarfs Through Multiplicity Studies (pp. –).

    Low-Mass Pre–Main Sequence Stars and Their X-ray Emission circumstellar environment, but x-rays can penetrate the dense clouds. As the protostar than in low-mass stars. Intermediate-mass stars (Herbig Ae/Be stars) in their pre-MS phase evolve more slowly and reach the MS. The current model of classical T Tauri stars (= CTTS; low-mass pre-main sequence stars with strong emission lines and near-infrared excess emission; Hartmann ()) involves accretion from a circumstellar disk at modest lly, it was thought that accretion disks extended all the way to the stellar photosphere, and that much of the accretion luminosity was released in a boundary Cited by:

    The observed structures are consistent with each object being a pre-main-sequence star with protoplanetary dust. The five objects' circumstellar environments could result from extreme youth and complex initial conditions, from asymmetric scattering patterns due to shadows cast by misaligned disks, or in some cases from interactions with companions. A Herbig Ae/Be star (HAeBe) is a pre-main-sequence star – a young (stars are still embedded in gas-dust envelopes and are sometimes accompanied by circumstellar disks. Hydrogen and calcium emission lines are observed in their spectra. They are Solar mass (M ☉) objects, still existing in the star formation (gravitational contraction) stage.


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The circumstellar environments of intermediate mass main sequence stars Download PDF EPUB FB2

The circumstellar environments of intermediate mass main sequence stars: a final report. [Carol Grady; United States.

National Aeronautics and Space Administration.]. Mass loss from the surface is the most important phenomenon for the final evolution of low-and intermediate-mass (M) stars on the asymptotic giant : Hans Olofsson.

Key words. circumstellar matter – stars: pre-main sequence – stars: individual (R Mon, PDS 27) – protoplanetary discs – ISM: molecules – astrochemistry 1. Introduction Low- and intermediate-mass star formation theory assumes that stellar masses are accumulated as a consequence of gravitationalCited by: 4.

Circumstellar envelopes of intermediate mass young stars. By Rodrigo Georgetti Vieira. stars in the pre-main sequence. Some of their properties remain not well understood to date. Only a full multi-wavelength study is able to reveal a reasonable scenario for their circumstellar material.

The purpose of the present work is to study the Author: Rodrigo Georgetti Vieira. Keywords:stars:circumstellarmatter–stars:formation–stars: individual: UX Ori 1. Introduction UXOri is a Herbig Ae/Be (HAe/Be) star, i.e., a pre-main– sequence star of intermediate mass, located at a distance of about pc.

It has spectral type A3, mass M?˘M, and age ˘ 2 yr, based on its location on the HR diagram. The. In this dissertation, I present nulling interferometric observations of intermediate mass stars and their circumstellar environments.

The observations constrain physical processes with regard to the evolution of circumstellar dust in primordial disks, as well as debris disks in main sequence objects.

Observations were made in the N-band (near 10 mm) which traces primarily thermal emission from Author: Wilson Michael Liu. which the circumstellar material is replenished via collisions between orbiting bodies is not well understood.

Additionally, intermediate mass stars provide a link between disk evolution in low mass, post-T Tauri stars, and high mass pre-main sequence stars such as those found in ultra-compact HII regions (Waters & Waelkens ). We have obtained high spatial resolution mid-IR observations of four intermediate-mass pre-main-sequence stars: HDASLkHαand MWC Our observations reveal the morphology of the circumstellar (, AU) environments of these young stars.

Using these details we then simulate the evolution of the circumstellar environment up to the point before an SN or GRB will occur.

We then discuss how the circumstellar environment varies over the initial mass and metallicity of the stars and the initial density of the interstellar medium (ISM).Cited by: Evolution of Intermediate-Mass Stars • large convective cores on main-sequence (up to 80% or more of M) • effect of convective overshooting very important: – larger convective cores – extends lifetime on main-sequence – leads to higher luminosity and broader MS.

Circumstellar disks surrounding young forming stars, are likely the location where planets form. While the gaseous phase represents up to ˜99% of the disk mass and control the dynamics, most of. High resolution interferometer and single-dish observations of young, deeply embedded stellar systems reveal a complex chemistry in the circumstellar environments of low to intermediate mass stars.

Depletions of gas-phase molecules, grain mantle evaporation, and shock interactions actively drive chemical processes in different regions around Cited by: 2.

This chapter discusses the properties of the immediate circumstellar environment of pre-main-sequence stars of intermediate mass, or Herbig Ae/Be (HAeBe) stars, with particular emphasis on the properties and evolution of the circumstellar by: Context: The majority of the intermediate mass, pre-main-sequence Herbig Ae/Be stars reside in binary systems.

As these systems are young, their properties may contain an imprint of the star formation process at intermediate masses (M).Cited by: In this dissertation, I present nulling interferometric observations of intermediate mass stars and their circumstellar environments.

The observations constrain physical processes with regard to the evolution of circumstellar dust in primordial disks, as well as debris disks in main sequence : and Wilson Michael Liu and Wilson Michael Liu.

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Abstract. This paper presents new observations of UX Ori obtained with the millimeter interferometer of Plateau de Bure and with ISO.

UX Ori is the prototype of a group of pre-main– sequence, intermediate-mass stars, often indicated as precursors of β Pic. The interferometry observations at and mm show that. Abstract Circumstellar disks surrounding young forming stars, are likely the location where planets form.

While the gaseous phase represents up to ˜99% of the disk mass and control the dynamics, most of disk properties relies on dust analyses. The evolutionary state of most of these stars is not known. They are all post main sequence stars, but the intermediate{type or \yellow" hypergiants could be either evolving to cooler temperatures or be post-red supergiant (RSG) stars in transition to warmertemperatures.

deJager()hassuggested 1Astronomy Department, Church St. SE., Uni. NASA CR The Circumstellar Environments of Intermediate Mass Main Sequence Stars A FINAL REPORT NAS Submitted to: NASA/Goddard Space Flight Center Code Greenbelt, MD i Submitted by: Dr. Carol Grady Applied Research Corporation Corporate Drive Suite Landover, MD () ARC Report #: R Date.

Observational perspective of the youngest phases of intermediate mass stars by Maria Beltran Intermediate-mass protostars are the long-forgotten actors in the star formation scenario. Although their pre-main sequence evolution should be similar to those of low-mass protostars, they share many characteristics with their high-mass stars counterparts.

Abstract. We present Hα spectropolarimetry of a large sample of pre-main sequence (PMS) stars of low and intermediate mass, and argue that the technique is a powerful tool in studying the circumstellar geometry around these : Jorick S. Vink, Janet E.

Drew, Tim J. Harries, René D. Oudmaijer. We present ISO-SWS observations of H2 pure-rotational line emission from the disks around low and intermediate mass pre-main-sequence stars as well as from young stars thought to be surrounded by debris disks.

We detect `warm' (T ~ K) H2 gas around many sources, including tentatively the debris-disk objects.Photoevaporation of Circumstellar Disks By Far-Ultraviolet, Extreme-Ultraviolet and X-Ray Radiation from the Central Star U.

Gorti and D. Hollenbach The Astrophysical Journal IOPscience. Assembling the Building Blocks of Giant Planets Around Intermediate-Mass Stars K.

A. Kretke et al. The Astrophysical Journal