University of Hertfordshire

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By the same authors

Documents

  • Stephen R. Kane
  • Paul A. Dalba
  • Zhexing Li
  • Elliott P. Horch
  • Lea A. Hirsch
  • Jonathan Horner
  • Robert A. Wittenmyer
  • Steve B. Howell
  • Mark E. Everett
  • R. Paul Butler
  • Christopher G. Tinney
  • Brad D. Carter
  • Duncan J. Wright
  • Hugh R. A. Jones
  • Jeremy Bailey
  • Simon J. O'Toole
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Original languageEnglish
JournalThe Astronomical Journal
Journal publication date4 Jun 2019
DOIs
Publication statusPublished - 4 Jun 2019

Abstract

The sensitivity of radial velocity (RV) surveys for exoplanet detection are extending to increasingly long orbital periods, where companions with periods of several years are now being regularly discovered. Companions with orbital periods that exceed the duration of the survey manifest in the data as an incomplete orbit or linear trend, a feature that can either present as the sole detectable companion to the host star, or as an additional signal overlain on the signatures of previously discovered companion(s). A diagnostic that can confirm or constrain scenarios in which the trend is caused by an unseen stellar, rather than planetary, companion is the use of high-contrast imaging observations. Here, we present RV data from the Anglo-Australian Planet Search (AAPS) for twenty stars that show evidence of orbiting companions. Of these, six companions have resolved orbits, with three that lie in the planetary regime. Two of these (HD~92987b and HD~221420b) are new discoveries. Follow-up observations using the Differential Speckle Survey Instrument (DSSI) on the Gemini South telescope revealed that five of the twenty monitored companions are likely stellar in nature. We use the sensitivity of the AAPS and DSSI data to place constraints on the mass of the companions for the remaining systems. Our analysis shows that a planetary-mass companion provides the most likely self-consistent explanation of the data for many of the remaining systems.

Notes

13 pages, 6 figures, 4 tables, accepted for publication in the Astronomical Journal (submitted 25 Feb 2019; accepted 28 April 2019). Machine readable tables and Posteriors from the RadVel fits are available here: http://stephenkane.net/rvfits.tar

ID: 16903368