Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1

Creators: Bohn, Alexander J.; Kenworthy, Matthew A.; Ginski, Christian; Rieder, Steven; Mamajek, Eric E.; Meshkat, Tiffany; Pecaut, Mark J.; Reggiani, Maddalena; de Boer, Jozua; Keller, Christoph U.; Snik, Frans; Southworth, John

Abstract

Even though tens of directly imaged companions have been discovered in the past decades, the number of directly confirmed multiplanet systems is still small. Dynamical analysis of these systems imposes important constraints on formation mechanisms of these wide-orbit companions. As part of the Young Suns Exoplanet Survey we report the detection of a second planetary-mass companion around the 17 Myr-old, solar-type star TYC 8998-760-1 that is located in the Lower Centaurus Crux subgroup of the Scorpius–Centaurus association. The companion has a projected physical separation of 320 au and several individual photometric measurements from 1.1 to 3.8 microns constrain a companion mass of 6 ± 1 M_(Jup), which is equivalent to a mass ratio of q = 0.57 ± 0.10% with respect to the primary. With the previously detected 14 ± 3 M_(Jup) companion that is orbiting the primary at 160 au, TYC 8998-760-1 is the first directly imaged multiplanet system that is detected around a young, solar analog. We show that circular orbits are stable, but that mildly eccentric orbits for either/both components (e > 0.1) are chaotic on gigayear timescales, implying in situ formation or a very specific ejection by an unseen third companion. Due to the wide separations of the companions TYC 8998-760-1 is an excellent system for spectroscopic and photometric follow-up with space-based observatories such as the James Webb Space Telescope.

Additional Information

© 2020 The American Astronomical Society. Received 2020 April 23; revised 2020 July 1; accepted 2020 July 3; published 2020 July 22. We thank the anonymous referee for valuable feedback that helped improve the quality of the manuscript. The research of A.J.B. and F.S. leading to these results has received funding from the European Research Council under ERC Starting Grant agreement 678194 (FALCONER). S.R. acknowledges funding from the STFC Consolidated Grant ST/R000395/1. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. M.R. acknowledges support from the Fonds Wetenschappelijk Onderzoek (FWO, Research Foundation Flanders) under project ID G0B3818N. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France (Wenger et al. 2000). This publication makes use of VOSA, developed under the Spanish Virtual Observatory project supported by the Spanish MINECO through grant AyA2017-84089. VOSA has been partially updated by using funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 776403 (EXOPLANETS-A). To achieve the scientific results presented in this article we made use of the Python programming language¹², especially the SciPy (Virtanen et al. 2020), NumPy (Oliphant 2006), Matplotlib (Hunter 2007), emcee (Foreman-Mackey et al. 2013), scikit-image (van der Walt et al. 2014), scikit-learn (Pedregosa et al. 2012), photutils (Bradley et al. 2016), and astropy (Astropy Collaboration et al. 2013, 2018) packages. We performed simulations using Rebound (Rein & Liu 2012) and AMUSE (Pelupessy et al. 2013). Facility: ESO/VLT/SPHERE ESO/VLT/NACO. - Software: SciPy (Virtanen et al. 2020), NumPy (Oliphant 2006), Matplotlib (Hunter 2007), emcee (Foreman-Mackey et al. 2013), scikit-image (van der Walt et al. 2014), scikit-learn (Pedregosa et al. 2012), photutils (Bradley et al. 2016), astropy (Astropy Collaboration et al. 2013, 2018), Rebound (Rein & Liu 2012) and AMUSE (Pelupessy et al. 2013).

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