TESS discovery of a super-Earth and two sub-Neptunes orbiting the bright, nearby, Sun-like star HD 22946

Creators: Cacciapuoti, Luca; Inno, Laura; Covone, Giovanni; Kostov, Veselin B.; Barclay, Thomas; Quintana, Elisa V.; Colón, Knicole D.; Stassun, Keivan G.; Hord, Benjamin J.; Giacalone, Steven; Kane, Stephen R.; Hoffman, Kelsey; Rowe, Jason; Wang, Gavin; Collins, Kevin I.; Collins, Karen A.; Tan, Thiam-Guan; Gallo, Francesco; Magliano, Christian; Ienco, Riccardo M.; Rabus, Markus; Ciardi, David R.; Furlan, Elise; Howell, Steve B.; Gnilka, Crystal L.; Scott, Nicholas J.; Lester, Kathryn V.; Ziegler, Carl; Briceño, César; Law, Nicholas; Mann, Andrew W.; Burke, Christopher J.; Quinn, Samuel N.; Ciaramella, Angelo; De Luca, Pasquale; Fiscale, Stefano; Rotundi, Alessandra; Marcellino, Livia; Galletti, Ardelio; Bifulco, Ida; Oliva, Fabrizio; Spencer, Alton; Kaltenegger, Lisa; McDermott, Scott; Essack, Zahra; Jenkins, Jon M.; Wohler, Bill; Winn, Joshua N.; Seager, S.; Vanderspek, Roland; Zhou, George; Shporer, Avi; Dragomir, Diana; Fong, William

Abstract

We report the Transiting Exoplanet Survey Satellite (TESS) discovery of a three-planet system around the bright Sun-like star HD 22946 (V ≈ 8.3 mag), also known as TIC 100990000, located 63 pc from Earth. The system was observed by TESS in Sectors 3, 4, 30, and 31 and two planet candidates, labeled TESS Objects of Interest (TOIs) 411.01 (planet c) and 411.02 (planet b), were identified on orbits of 9.57 and 4.04 days, respectively. In this work, we validate the two planets and recover an additional single transit-like signal in the light curve, which suggests the presence of a third transiting planet with a longer period of about 46 days. We assess the veracity of the TESS transit signals and use follow-up imaging and time-series photometry to rule out false-positive scenarios, including unresolved binary systems, nearby eclipsing binaries, and contamination of the light curves by background or foreground stars. Parallax measurements from Gaia Early Data Release 3 together with broad-band photometry and spectroscopic follow-up by the TESS FollowUp Observing Program (TFOP) allowed us to constrain the stellar parameters of TOI-411, including its radius of 1.157 ± 0.025 R_⊙. Adopting this value, we determined the radii for the three exoplanet candidates and found that planet b is a super-Earth with a radius of 1.48 ± 0.06 R_⊕, while planets c and d are sub-Neptunian planets with radii of 2.35 ± 0.08 R_⊕ and 2.78 ± 0.13 R_⊕ respectively. Using dynamical simulations, we assessed the stability of the system and evaluated the possibility of the presence of other undetected, non-transiting planets by investigating its dynamical packing. We find that the system is dynamically stable and potentially unpacked, with enough space to host at least one more planet between c and d. Finally, given that the star is bright and nearby, we discuss possibilities for detailed mass characterisation of its surrounding worlds and opportunities for the detection of their atmospheres with the James Webb Space Telescope.

Additional Information

© L. Cacciapuoti et al. 2022. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe-to-Open model. Subscribe to A&A to support open access publication. We thank the referee for her/his comments that helped to improve and clarify the presentation of our results. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by NASA's Science Mission Directorate. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. L.I. acknowledges the "PON Ricerca e Innovazione: Attraction and International Mobility (AIM)" program for support. 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, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Observations in the paper made use of the High-Resolution Imaging instrument Zorro at Gemini-South. The data underlying this article is publicly available at the following archives: MAST (https://archive.stsci.edu/missions-and-data/tess) and ExoFOP-TESS (https://exofop.ipac.caltech.edu/tess/). This work is based on data collected at the following facilities: ASAS-SN, Exoplanet Archive, Gaia, Gemini: South (Zorro), MAST, LCOGT, SOAR (HRcam), TESS. This work makes use of the following software: astropy, lightkurve (Lightkurve Collaboration 2018), transitleastsquares (Hippke & Heller 2019), DAVE (Kostov et al. 2019), exoplanet (Foreman-Mackey et al. 2017; Foreman-Mackey 2018), vespa (Morton 2015), triceratops (Giacalone & Dressing 2020), tpfplotter (Aller et al. 2020).

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