Abstract
We investigated the discrepancy between planetary mass determinations using the transit timing variations (TTVs) and radial velocities (RVs), by analysing the multiplanet system Kepler-9. Despite being the first system characterized with TTVs, there are several discrepant solutions in the literature, with those reporting lower planetary densities being apparently in disagreement with high-precision RV observations. To resolve this, we gathered HARPS-N RVs at epochs that maximized the difference between the predicted RV curves from discrepant solutions in the literature. We also reanalysed the full Kepler data set and performed a dynamical fit, within a Bayesian framework, using the newly derived central and duration times of the transits. We compared these results with the RV data and found that our solution better describes the RV observations, despite the masses of the planets being nearly half that presented in the discovery paper. We therefore confirm that the TTV method can provide mass determinations that agree with those determined using high-precision RVs. The low densities of the planets place them in the scarcely populated region of the super-Neptunes/inflated sub-Saturns in the mass-radius diagram.
| Original language | English |
|---|---|
| Pages (from-to) | 3233-3243 |
| Number of pages | 11 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 484 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 11 Apr 2019 |
Bibliographical note
Funding Information:Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St.Andrews, Queen's University Belfast, and the University of Edinburgh. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH) and support from Italian Space Agency (ASI) regulated by Accordo ASI-INAF no. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; ht tps://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. LM acknowledges the support by INAF/Frontiera through the 'Pro-getti Premiali' funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. XD is grateful to The Branco Weiss Fellowship - Society in Science for its financial support. CAW acknowledges support from the STFC grant ST/P000312/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithsonian Astrophysical Observatory. This material is based upon work supported by the National Aeronautics and Space Administration under grant nos. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the Exoplanet Follow-up Observation Program, NASA's Astrophysics Data System, and the NASA Exoplanet Archive, which are operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts.
Funding Information:
by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen’s University Belfast, and the University of Edinburgh. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement number 313014 (ETAEARTH) and support from Italian Space Agency (ASI) regulated by Accordo ASI-INAF no. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; ht tps://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. LM acknowledges the support by INAF/Frontiera through the ‘Pro-getti Premiali’ funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. XD is grateful to The Branco Weiss Fellowship – Society in Science for its financial support. CAW acknowledges support from the STFC grant ST/P000312/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithso-nian Astrophysical Observatory. This material is based upon work supported by the National Aeronautics and Space Administration under grant nos. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the Exoplanet Follow-up Observation Program, NASA’s Astrophysics Data System, and the NASA Exoplanet Archive, which are operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts.
Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
Keywords
- Stars: fundamental parameters
- Stars: individual: Kepler-9
- Techniques: radial velocities
- Techniques: spectroscopic
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science