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Title: High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability

Abstract

We report on the H -band spectral variability of classical Be stars observed over the course of the Apache Point Galactic Evolution Experiment (APOGEE), one of four subsurveys comprising SDSS-III. As described in the first paper of this series, the APOGEE B-type emission-line (ABE) star sample was culled from the large number of blue stars observed as telluric standards during APOGEE observations. In this paper, we explore the multi-epoch ABE sample, consisting of 1100 spectra for 213 stars. These “snapshots” of the circumstellar disk activity have revealed a wealth of temporal variability including, but not limited to, gradual disappearance of the line emission and vice versa over both short and long timescales. Other forms of variability include variation in emission strength, emission peak intensity ratios, and emission peak separations. We also analyze radial velocities (RVs) of the emission lines for a subsample of 162 stars with sufficiently strong features, and we discuss on a case-by-case basis whether the RV variability exhibited by some stars is caused by binary motion versus dynamical processes in the circumstellar disks. Ten systems are identified as convincing candidates for binary Be stars with as of yet undetected companions.

Authors:
;  [1];  [2];  [3]; ;  [4];  [5];  [6];  [7];  [8]; ;  [9];  [10];  [11];  [12]
  1. Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States)
  2. Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States)
  3. Department of Physics, Austin College, 900 N. Grand Avenue, Sherman, TX 75090 (United States)
  4. Department of Physics, Lehigh University, Bethlehem, PA 18015 (United States)
  5. Observatório Nacional, Rua General José Cristino 77, 20921-400, São Cristovão, Rio de Janeiro (Brazil)
  6. Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road Shanghai 200030 (China)
  7. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)
  8. Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, Colorado 80309-0389 (United States)
  9. Departamento de Astronomía, Universidad de Concepción, Concepción (Chile)
  10. Departamento de Física, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena (Chile)
  11. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)
  12. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218 (United States)
Publication Date:
OSTI Identifier:
22663723
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 153; Journal Issue: 4; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTRA; ABSORPTION SPECTROSCOPY; EMISSION; GALACTIC EVOLUTION; RADIAL VELOCITY; RESOLUTION; STARS; VARIATIONS

Citation Formats

Chojnowski, S. Drew, Holtzman, Jon A., Wisniewski, John P., Whelan, David G., Labadie-Bartz, Jonathan, Pepper, Joshua, Fernandes, Marcelo Borges, Lin, Chien-Cheng, Majewski, Steven R., Stringfellow, Guy S., Mennickent, Ronald E., Tang, Baitian, Roman-Lopes, Alexandre, Hearty, Fred R., and Zasowski, Gail. High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability. United States: N. p., 2017. Web. doi:10.3847/1538-3881/AA64CE.
Chojnowski, S. Drew, Holtzman, Jon A., Wisniewski, John P., Whelan, David G., Labadie-Bartz, Jonathan, Pepper, Joshua, Fernandes, Marcelo Borges, Lin, Chien-Cheng, Majewski, Steven R., Stringfellow, Guy S., Mennickent, Ronald E., Tang, Baitian, Roman-Lopes, Alexandre, Hearty, Fred R., & Zasowski, Gail. High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability. United States. doi:10.3847/1538-3881/AA64CE.
Chojnowski, S. Drew, Holtzman, Jon A., Wisniewski, John P., Whelan, David G., Labadie-Bartz, Jonathan, Pepper, Joshua, Fernandes, Marcelo Borges, Lin, Chien-Cheng, Majewski, Steven R., Stringfellow, Guy S., Mennickent, Ronald E., Tang, Baitian, Roman-Lopes, Alexandre, Hearty, Fred R., and Zasowski, Gail. Sat . "High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability". United States. doi:10.3847/1538-3881/AA64CE.
@article{osti_22663723,
title = {High-resolution H -band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability},
author = {Chojnowski, S. Drew and Holtzman, Jon A. and Wisniewski, John P. and Whelan, David G. and Labadie-Bartz, Jonathan and Pepper, Joshua and Fernandes, Marcelo Borges and Lin, Chien-Cheng and Majewski, Steven R. and Stringfellow, Guy S. and Mennickent, Ronald E. and Tang, Baitian and Roman-Lopes, Alexandre and Hearty, Fred R. and Zasowski, Gail},
abstractNote = {We report on the H -band spectral variability of classical Be stars observed over the course of the Apache Point Galactic Evolution Experiment (APOGEE), one of four subsurveys comprising SDSS-III. As described in the first paper of this series, the APOGEE B-type emission-line (ABE) star sample was culled from the large number of blue stars observed as telluric standards during APOGEE observations. In this paper, we explore the multi-epoch ABE sample, consisting of 1100 spectra for 213 stars. These “snapshots” of the circumstellar disk activity have revealed a wealth of temporal variability including, but not limited to, gradual disappearance of the line emission and vice versa over both short and long timescales. Other forms of variability include variation in emission strength, emission peak intensity ratios, and emission peak separations. We also analyze radial velocities (RVs) of the emission lines for a subsample of 162 stars with sufficiently strong features, and we discuss on a case-by-case basis whether the RV variability exhibited by some stars is caused by binary motion versus dynamical processes in the circumstellar disks. Ten systems are identified as convincing candidates for binary Be stars with as of yet undetected companions.},
doi = {10.3847/1538-3881/AA64CE},
journal = {Astronomical Journal (Online)},
number = 4,
volume = 153,
place = {United States},
year = {Sat Apr 01 00:00:00 EDT 2017},
month = {Sat Apr 01 00:00:00 EDT 2017}
}