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Title: MASS AND LUMINOSITY EVOLUTION OF YOUNG STELLAR OBJECTS

Abstract

A model of protostar mass and luminosity evolution in clusters gives new estimates of cluster age, protostar birthrate, accretion rate, and mean accretion time. The model assumes constant protostar birthrate, core-clump accretion, and equally likely accretion stopping. Its parameters are set to reproduce the initial mass function and to match protostar luminosity distributions in nearby star-forming regions. It obtains cluster ages and birthrates from the observed numbers of protostars and pre-main sequence (PMS) stars, and from the modal value of the protostar luminosity. In 31 embedded clusters and complexes, the global cluster age is 1-3 Myr, matching available estimates based on optical spectroscopy (OS) and evolutionary tracks. This method of age estimation is simpler than OS and is more useful for young embedded clusters where optical spectroscopy is not possible. In the youngest clusters, the protostar fraction decreases outward from the densest gas, indicating that the local star-forming age increases outward from a few 0.1 Myr in small protostar-dominated zones to a few Myr in large PMS-dominated zones.

Authors:
 [1]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22037123
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 752; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTROSCOPY; AGE ESTIMATION; ASTRONOMY; ASTROPHYSICS; DISTRIBUTION; EMISSION SPECTROSCOPY; LUMINOSITY; MASS; PROTOSTARS; STAR CLUSTERS; STAR EVOLUTION; STARS; ZONES

Citation Formats

Myers, Philip C., E-mail: pmyers@cfa.harvard.edu. MASS AND LUMINOSITY EVOLUTION OF YOUNG STELLAR OBJECTS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/752/1/9.
Myers, Philip C., E-mail: pmyers@cfa.harvard.edu. MASS AND LUMINOSITY EVOLUTION OF YOUNG STELLAR OBJECTS. United States. doi:10.1088/0004-637X/752/1/9.
Myers, Philip C., E-mail: pmyers@cfa.harvard.edu. Sun . "MASS AND LUMINOSITY EVOLUTION OF YOUNG STELLAR OBJECTS". United States. doi:10.1088/0004-637X/752/1/9.
@article{osti_22037123,
title = {MASS AND LUMINOSITY EVOLUTION OF YOUNG STELLAR OBJECTS},
author = {Myers, Philip C., E-mail: pmyers@cfa.harvard.edu},
abstractNote = {A model of protostar mass and luminosity evolution in clusters gives new estimates of cluster age, protostar birthrate, accretion rate, and mean accretion time. The model assumes constant protostar birthrate, core-clump accretion, and equally likely accretion stopping. Its parameters are set to reproduce the initial mass function and to match protostar luminosity distributions in nearby star-forming regions. It obtains cluster ages and birthrates from the observed numbers of protostars and pre-main sequence (PMS) stars, and from the modal value of the protostar luminosity. In 31 embedded clusters and complexes, the global cluster age is 1-3 Myr, matching available estimates based on optical spectroscopy (OS) and evolutionary tracks. This method of age estimation is simpler than OS and is more useful for young embedded clusters where optical spectroscopy is not possible. In the youngest clusters, the protostar fraction decreases outward from the densest gas, indicating that the local star-forming age increases outward from a few 0.1 Myr in small protostar-dominated zones to a few Myr in large PMS-dominated zones.},
doi = {10.1088/0004-637X/752/1/9},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 752,
place = {United States},
year = {2012},
month = {6}
}