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

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

Submitted on 20 September 2022


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 parsecs away.The system was observed by TESS in Sectors 3, 4, 30 and 31 and two planet candidates, labelled 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 or background/foreground stars contaminating the light curves. Parallax measurements from Gaia EDR3, together with broad-band photometry and spectroscopic follow-up by TFOP allowed us to constrain the stellar parameters of TOI-411, including its radius of1.157±0.025R. 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 1.72±0.10R, while planet c and d are sub-Neptunian planets, with radii of2.74±0.14R and 3.23±0.19R respectively. By 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 and .(Abridged)


Comment: 21 pages, 12 figures. Accepted for publication on A&A

Subject: Astrophysics - Earth and Planetary Astrophysics