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Title: Measuring the mass of a pre-main sequence binary star through the orbit of TWA5A

Abstract

We present the results of a five year monitoring campaign of the close binary TWA 5Aab in the TW Hydrae association, using speckle and adaptive optics on the W.M. Keck 10 m telescopes. These measurements were taken as part of our ongoing monitoring of pre-main sequence (PMS) binaries in an effort to increase the number of dynamically determined PMS masses and thereby calibrate the theoretical PMS evolutionary tracks. Our observations have allowed us to obtain the first determination of this system's astrometric orbit. We find an orbital period of 5.94 {+-} 0.09 years and a semi-major axis of 0.''066 {+-} 0.''005. Combining these results with a kinematic distance, we calculate a total mass of 0.71 {+-} 0.14 M{sub {circle_dot}} (D/44 pc){sup 3}. for this system. This mass measurement, as well as the estimated age of this system, are consistent to within 2{sigma} of all theoretical models considered. In this analysis, we properly account for correlated uncertainties, and show that while these correlations are generally ignored, they increase the formal uncertainties by up to a factor of five and therefore are important to incorporate. With only a few more years of observation, this type of measurement will allow the theoretical modelsmore » to be distinguished.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
908087
Report Number(s):
UCRL-JRNL-227824
Journal ID: ISSN 0004-6256; ANJOAA; TRN: US200722%%413
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal, vol. 133, no. 5, May 1, 2007, pp. 2008-2014; Journal Volume: 133; Journal Issue: 5
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; BINARY STARS; MONITORING; OPTICS; TELESCOPES

Citation Formats

Konopacky, Q, Ghez, A, Duchene, G, McCabe, C, and Macintosh, B. Measuring the mass of a pre-main sequence binary star through the orbit of TWA5A. United States: N. p., 2007. Web.
Konopacky, Q, Ghez, A, Duchene, G, McCabe, C, & Macintosh, B. Measuring the mass of a pre-main sequence binary star through the orbit of TWA5A. United States.
Konopacky, Q, Ghez, A, Duchene, G, McCabe, C, and Macintosh, B. Thu . "Measuring the mass of a pre-main sequence binary star through the orbit of TWA5A". United States. doi:. https://www.osti.gov/servlets/purl/908087.
@article{osti_908087,
title = {Measuring the mass of a pre-main sequence binary star through the orbit of TWA5A},
author = {Konopacky, Q and Ghez, A and Duchene, G and McCabe, C and Macintosh, B},
abstractNote = {We present the results of a five year monitoring campaign of the close binary TWA 5Aab in the TW Hydrae association, using speckle and adaptive optics on the W.M. Keck 10 m telescopes. These measurements were taken as part of our ongoing monitoring of pre-main sequence (PMS) binaries in an effort to increase the number of dynamically determined PMS masses and thereby calibrate the theoretical PMS evolutionary tracks. Our observations have allowed us to obtain the first determination of this system's astrometric orbit. We find an orbital period of 5.94 {+-} 0.09 years and a semi-major axis of 0.''066 {+-} 0.''005. Combining these results with a kinematic distance, we calculate a total mass of 0.71 {+-} 0.14 M{sub {circle_dot}} (D/44 pc){sup 3}. for this system. This mass measurement, as well as the estimated age of this system, are consistent to within 2{sigma} of all theoretical models considered. In this analysis, we properly account for correlated uncertainties, and show that while these correlations are generally ignored, they increase the formal uncertainties by up to a factor of five and therefore are important to incorporate. With only a few more years of observation, this type of measurement will allow the theoretical models to be distinguished.},
doi = {},
journal = {Astronomical Journal, vol. 133, no. 5, May 1, 2007, pp. 2008-2014},
number = 5,
volume = 133,
place = {United States},
year = {Thu Jan 18 00:00:00 EST 2007},
month = {Thu Jan 18 00:00:00 EST 2007}
}
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