A Decade of Radial-velocity Monitoring of Vega and New Limits on the Presence of Planets
Article
Article Title | A Decade of Radial-velocity Monitoring of Vega and New Limits on the Presence of Planets |
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ERA Journal ID | 1048 |
Article Category | Article |
Authors | Hurt, Spencer A. (Author), Quinn, Samuel N. (Author), Latham, David W. (Author), Vanderburg, Andrew (Author), Esquerdo, Gilbert A. (Author), Calkins, Michael L. (Author), Berlind, Perry (Author), Angus, Ruth (Author), Latham, Christian A. (Author) and Zhou, George (Author) |
Journal Title | The Astronomical Journal |
Journal Citation | 161 (4), pp. 1-14 |
Article Number | 157 |
Number of Pages | 14 |
Year | 2021 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-6256 |
1538-3881 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-3881/abdec8 |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-3881/abdec8 |
Abstract | We present an analysis of 1524 spectra of Vega spanning 10 yr, in which we search for periodic radial-velocity variations. A signal with a periodicity of 0.676 day and a semi-amplitude of ∼10 m s-1 is consistent with the rotation period measured over much shorter time spans by previous spectroscopic and spectropolarimetric studies, confirming the presence of surface features on this A0 star. The activity signal appears to evolve on long timescales, which may indicate the presence of failed fossil magnetic fields on Vega. TESS data reveal Vega’s photometric rotational modulation for the first time, with a total amplitude of only 10 ppm. A comparison of the spectroscopic and photometric amplitudes suggests that the surface features may be dominated by bright plages rather than dark spots. For the shortest orbital periods, transit and radial-velocity injection recovery tests exclude the presence of transiting planets larger than 2 R and most non-transiting giant planets. At long periods, we combine our radial velocities with direct imaging from the literature to produce detection limits for Vegan planets and brown dwarfs out to distances of 15 au. Finally, we detect a candidate radial-velocity signal with a period of 2.43 days and a semi-amplitude of 6 m s-1. If caused by an orbiting companion, its minimum mass would be ∼20 M; because of Vega’s pole-on orientation, this would correspond to a Jovian planet if the orbit is aligned with the stellar spin. We discuss the prospects for confirmation of this candidate planet. |
Keywords | Exoplanet astronomy; Exoplanet detection methods; Exoplanets; Stellar; activity; Stellar magnetic fields; Photometry; Radial velocity; Circumstellar disks; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar and Stellar Astrophysics |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | For access to this article, please click on the URL link provided. |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | University of Colorado Boulder, United States |
Center for Astrophysics Harvard and Smithsonian, United States | |
Harvard-Smithsonian Centre for Astrophysics, United States | |
University of Wisconsin-Madison, United States | |
American Museum of Natural History, United States |
https://research.usq.edu.au/item/q6x43/a-decade-of-radial-velocity-monitoring-of-vega-and-new-limits-on-the-presence-of-planets
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