skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: MAGNETOSPHERIC ACCRETION IN CLOSE PRE-MAIN-SEQUENCE BINARIES

Abstract

The transfer of matter between a circumbinary disk and a young binary system remains poorly understood, obscuring the interpretation of accretion indicators. To explore the behavior of these indicators in multiple systems, we have performed the first systematic time-domain study of young binaries in the ultraviolet. We obtained far- and near-ultraviolet HST/COS spectra of the young spectroscopic binaries DQ Tau and UZ Tau E. Here we focus on the continuum from 2800 to 3200 Å and on the C iv doublet (λλ1548.19, 1550.77 Å) as accretion diagnostics. Each system was observed over three or four consecutive binary orbits, at phases ∼0, 0.2, 0.5, and 0.7. Those observations are complemented by ground-based U-band measurements. Contrary to model predictions, we do not detect any clear correlation between accretion luminosity and phase. Further, we do not detect any correlation between C iv flux and phase. For both stars the appearance of the C iv line is similar to that of single Classical T Tauri Stars (CTTSs), despite the lack of stable long-lived circumstellar disks. However, unlike the case in single CTTSs, the narrow and broad components of the C iv lines are uncorrelated, and we argue that the narrow component is powered bymore » processes other than accretion, such as flares in the stellar magnetospheres and/or enhanced activity in the upper atmosphere. We find that both stars contribute equally to the narrow component C iv flux in DQ Tau, but the primary dominates the narrow component C iv emission in UZ Tau E. The C iv broad component flux is correlated with other accretion indicators, suggesting an accretion origin. However, the line is blueshifted, which is inconsistent with its origin in an infall flow close to the star. It is possible that the complicated geometry of the region, as well as turbulence in the shock region, are responsible for the blueshifted line profiles.« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. The Aerospace Corporation, M2-266, El Segundo, CA 90245 (United States)
  2. Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States)
  3. The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
  4. Department of Astronomy, University of Wisconsin—Madison, Madison, WI 53706-1582 (United States)
  5. University of Nariño Observatory, Pasto, Nario (Colombia)
Publication Date:
OSTI Identifier:
22525321
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 811; Journal Issue: 2; 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; BINARY STARS; CARBON IONS; CORRELATIONS; EMISSION SPECTRA; INDICATORS; LUMINOSITY; ORBITS; STAR ACCRETION; STELLAR MAGNETOSPHERES; T TAURI STARS; TURBULENCE; ULTRAVIOLET RADIATION; ULTRAVIOLET SPECTRA

Citation Formats

Ardila, David R., Jonhs-Krull, Christopher, Herczeg, Gregory J., Mathieu, Robert D., and Quijano-Vodniza, Alberto, E-mail: David.Ardila@aero.org. MAGNETOSPHERIC ACCRETION IN CLOSE PRE-MAIN-SEQUENCE BINARIES. United States: N. p., 2015. Web. doi:10.1088/0004-637X/811/2/131.
Ardila, David R., Jonhs-Krull, Christopher, Herczeg, Gregory J., Mathieu, Robert D., & Quijano-Vodniza, Alberto, E-mail: David.Ardila@aero.org. MAGNETOSPHERIC ACCRETION IN CLOSE PRE-MAIN-SEQUENCE BINARIES. United States. doi:10.1088/0004-637X/811/2/131.
Ardila, David R., Jonhs-Krull, Christopher, Herczeg, Gregory J., Mathieu, Robert D., and Quijano-Vodniza, Alberto, E-mail: David.Ardila@aero.org. Thu . "MAGNETOSPHERIC ACCRETION IN CLOSE PRE-MAIN-SEQUENCE BINARIES". United States. doi:10.1088/0004-637X/811/2/131.
@article{osti_22525321,
title = {MAGNETOSPHERIC ACCRETION IN CLOSE PRE-MAIN-SEQUENCE BINARIES},
author = {Ardila, David R. and Jonhs-Krull, Christopher and Herczeg, Gregory J. and Mathieu, Robert D. and Quijano-Vodniza, Alberto, E-mail: David.Ardila@aero.org},
abstractNote = {The transfer of matter between a circumbinary disk and a young binary system remains poorly understood, obscuring the interpretation of accretion indicators. To explore the behavior of these indicators in multiple systems, we have performed the first systematic time-domain study of young binaries in the ultraviolet. We obtained far- and near-ultraviolet HST/COS spectra of the young spectroscopic binaries DQ Tau and UZ Tau E. Here we focus on the continuum from 2800 to 3200 Å and on the C iv doublet (λλ1548.19, 1550.77 Å) as accretion diagnostics. Each system was observed over three or four consecutive binary orbits, at phases ∼0, 0.2, 0.5, and 0.7. Those observations are complemented by ground-based U-band measurements. Contrary to model predictions, we do not detect any clear correlation between accretion luminosity and phase. Further, we do not detect any correlation between C iv flux and phase. For both stars the appearance of the C iv line is similar to that of single Classical T Tauri Stars (CTTSs), despite the lack of stable long-lived circumstellar disks. However, unlike the case in single CTTSs, the narrow and broad components of the C iv lines are uncorrelated, and we argue that the narrow component is powered by processes other than accretion, such as flares in the stellar magnetospheres and/or enhanced activity in the upper atmosphere. We find that both stars contribute equally to the narrow component C iv flux in DQ Tau, but the primary dominates the narrow component C iv emission in UZ Tau E. The C iv broad component flux is correlated with other accretion indicators, suggesting an accretion origin. However, the line is blueshifted, which is inconsistent with its origin in an infall flow close to the star. It is possible that the complicated geometry of the region, as well as turbulence in the shock region, are responsible for the blueshifted line profiles.},
doi = {10.1088/0004-637X/811/2/131},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 811,
place = {United States},
year = {2015},
month = {10}
}