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Title: RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS

Abstract

Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured heremore » have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.« less

Authors:
 [1];  [2];  [3]; ;  [4];  [5];  [6];  [7];  [8]
  1. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
  2. TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, Caltech, Pasadena, CA 91125 (United States)
  3. Department of Astronomy, University of California, Berkeley CA 94720 (United States)
  4. Department of Astrophysics and Planetary Science, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 (United States)
  5. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  6. Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom)
  7. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
  8. JILA, University of Colorado and NIST, 440 UCB, Boulder, 80309-0440 (United States)
Publication Date:
OSTI Identifier:
22667414
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 829; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BINARY STARS; DISTRIBUTION; EXCITATION; HEATING; ORBITS; OSCILLATION MODES; OSCILLATIONS; RADIAL VELOCITY; SPECTRA; VISIBLE RADIATION

Citation Formats

Shporer, Avi, Fuller, Jim, Isaacson, Howard, Hambleton, Kelly, Prša, Andrej, Thompson, Susan E., Kurtz, Donald W., Howard, Andrew W., and O’Leary, Ryan M.. RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS. United States: N. p., 2016. Web. doi:10.3847/0004-637X/829/1/34.
Shporer, Avi, Fuller, Jim, Isaacson, Howard, Hambleton, Kelly, Prša, Andrej, Thompson, Susan E., Kurtz, Donald W., Howard, Andrew W., & O’Leary, Ryan M.. RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS. United States. doi:10.3847/0004-637X/829/1/34.
Shporer, Avi, Fuller, Jim, Isaacson, Howard, Hambleton, Kelly, Prša, Andrej, Thompson, Susan E., Kurtz, Donald W., Howard, Andrew W., and O’Leary, Ryan M.. Tue . "RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS". United States. doi:10.3847/0004-637X/829/1/34.
@article{osti_22667414,
title = {RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS},
author = {Shporer, Avi and Fuller, Jim and Isaacson, Howard and Hambleton, Kelly and Prša, Andrej and Thompson, Susan E. and Kurtz, Donald W. and Howard, Andrew W. and O’Leary, Ryan M.},
abstractNote = {Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.},
doi = {10.3847/0004-637X/829/1/34},
journal = {Astrophysical Journal},
number = 1,
volume = 829,
place = {United States},
year = {Tue Sep 20 00:00:00 EDT 2016},
month = {Tue Sep 20 00:00:00 EDT 2016}
}