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Title: NEW X-RAY-SELECTED PRE-MAIN-SEQUENCE MEMBERS OF THE SERPENS MOLECULAR CLOUD

Abstract

The study of young stars no longer surrounded by disks can greatly add to our understanding of how protoplanetary disks evolve and planets form. We have used VLT/FLAMES optical spectroscopy to confirm the youth and membership of 19 new young diskless stars in the Serpens Molecular Cloud, identified at X-ray wavelengths. Spectral types, effective temperatures, and stellar luminosities were determined using optical spectra and optical/near-infrared photometry. Stellar masses and ages were derived based on pre-main-sequence evolutionary tracks. The results yield remarkable similarities for age and mass distribution between the diskless and disk-bearing stellar populations in Serpens. We discuss the important implications these similarities may have on the standard picture of disk evolution.

Authors:
 [1];  [2];  [3]
  1. McDonald Observatory, The University of Texas at Austin, 1 University Station, C1402, Austin, TX 78712 (United States)
  2. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  3. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22273341
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 146; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTROSCOPY; ASTRONOMY; ASTROPHYSICS; LUMINOSITY; MAIN SEQUENCE STARS; MASS; MASS DISTRIBUTION; NEAR INFRARED RADIATION; PHOTOMETRY; PLANETS; PROTOPLANETS; STAR EVOLUTION; X RADIATION

Citation Formats

Oliveira, Isa, Van der Laan, Margriet, and Brown, Joanna M., E-mail: oliveira@astro.as.utexas.edu. NEW X-RAY-SELECTED PRE-MAIN-SEQUENCE MEMBERS OF THE SERPENS MOLECULAR CLOUD. United States: N. p., 2013. Web. doi:10.1088/0004-6256/146/5/105.
Oliveira, Isa, Van der Laan, Margriet, & Brown, Joanna M., E-mail: oliveira@astro.as.utexas.edu. NEW X-RAY-SELECTED PRE-MAIN-SEQUENCE MEMBERS OF THE SERPENS MOLECULAR CLOUD. United States. doi:10.1088/0004-6256/146/5/105.
Oliveira, Isa, Van der Laan, Margriet, and Brown, Joanna M., E-mail: oliveira@astro.as.utexas.edu. 2013. "NEW X-RAY-SELECTED PRE-MAIN-SEQUENCE MEMBERS OF THE SERPENS MOLECULAR CLOUD". United States. doi:10.1088/0004-6256/146/5/105.
@article{osti_22273341,
title = {NEW X-RAY-SELECTED PRE-MAIN-SEQUENCE MEMBERS OF THE SERPENS MOLECULAR CLOUD},
author = {Oliveira, Isa and Van der Laan, Margriet and Brown, Joanna M., E-mail: oliveira@astro.as.utexas.edu},
abstractNote = {The study of young stars no longer surrounded by disks can greatly add to our understanding of how protoplanetary disks evolve and planets form. We have used VLT/FLAMES optical spectroscopy to confirm the youth and membership of 19 new young diskless stars in the Serpens Molecular Cloud, identified at X-ray wavelengths. Spectral types, effective temperatures, and stellar luminosities were determined using optical spectra and optical/near-infrared photometry. Stellar masses and ages were derived based on pre-main-sequence evolutionary tracks. The results yield remarkable similarities for age and mass distribution between the diskless and disk-bearing stellar populations in Serpens. We discuss the important implications these similarities may have on the standard picture of disk evolution.},
doi = {10.1088/0004-6256/146/5/105},
journal = {Astronomical Journal (New York, N.Y. Online)},
number = 5,
volume = 146,
place = {United States},
year = 2013,
month =
}
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  • We present the N{sub 2}H{sup +} (J = 1 → 0) map of the Serpens South molecular cloud obtained as part of the CARMA Large Area Star Formation Survey. The observations cover 250 arcmin{sup 2} and fully sample structures from 3000 AU to 3 pc with a velocity resolution of 0.16 km s{sup –1}, and they can be used to constrain the origin and evolution of molecular cloud filaments. The spatial distribution of the N{sub 2}H{sup +} emission is characterized by long filaments that resemble those observed in the dust continuum emission by Herschel. However, the gas filaments are typically narrower such that,more » in some cases, two or three quasi-parallel N{sub 2}H{sup +} filaments comprise a single observed dust continuum filament. The difference between the dust and gas filament widths casts doubt on Herschel ability to resolve the Serpens South filaments. Some molecular filaments show velocity gradients along their major axis, and two are characterized by a steep velocity gradient in the direction perpendicular to the filament axis. The observed velocity gradient along one of these filaments was previously postulated as evidence for mass infall toward the central cluster, but these kind of gradients can be interpreted as projection of large-scale turbulence.« less
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  • High-resolution echelle spectra of a main-sequence B type star (AV 304) in the Small Magellanic Cloud are analyzed using model atmosphere techniques to derive its atmospheric parameters and chemical composition. Because AV 340 is at an early evolutionary stage, its chemical composition should reflect that of its progenitor interstellar material. A general heavy element depletion of approximately -0.6 to -0.8 dex is deduced with nitrogen being more severely depleted and oxygen possibly less depleted. Helium has an approximately normal abundance. The high quality of the observational data coupled with the very small projected rotational velocity implies that depletions should normallymore » be accurate to better than + or - 0.2 dex, with the oxygen abundance probably being accurate to + or - 0.1 dex. 43 refs.« less