TESS discovery of a super-Earth and two sub-Neptunes orbiting the bright, nearby, Sun-like star HD 22946
Creators: name: Cacciapuoti, Luca
name: Inno, Laura
name: Covone, Giovanni
name: Kostov, Veselin B.
name: Barclay, Thomas
name: Quintana, Elisa V.
name: Colon, Knicole D.
name: Stassun, Keivan G.
name: Hord, Benjamin
name: Giacalone, Steven
name: Kane, Stephen R.
name: Hoffman, Kelsey
name: Rowe, Jason
name: Wang, Gavin
name: Collins, Kevin I.
name: Collins, Karen A.
name: Tan, Thiam-Guan
name: Gallo, Francesco
name: Magliano, Christian
name: Ienco, Riccardo M.
name: Rabus, Markus
name: Ciardi, David R.
name: Furlan, Elise
name: Howell, Steve B.
name: Gnilka, Crystal L.
name: Scott, Nicholas J.
name: Lester, Kathryn V.
name: Ziegler, Carl
name: Briceño, César
name: Law, Nicholas
name: Mann, Andrew W.
name: Burke, Christopher J.
name: Quinn, Samuel N.
name: Ciaramella, Angelo
name: De Luca, Pasquale
name: Fiscale, Stefano
name: Rotundi, Alessandra
name: Marcellino, Livia
name: Galletti, Ardelio
name: Bifulco, Ida
name: Oliva, Fabrizio
name: Spencer, Alton
name: Kaltenegger, Lisa
name: McDermott, Scott
name: Essack, Zahra
name: Jenkins, Jon M.
name: Wohler, Bill
name: Winn, Joshua N.
name: Seager, S.
name: Vanderspek, Roland
name: Zhou, George
name: Shporer, Avi
name: Dragomir, Diana
name: Fong, William
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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 of$1.157\pm0.025R_\odot$. 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 $1.72\pm0.10R_\oplus$, while planet $c$ and $d$ are sub-Neptunian planets, with radii of$2.74\pm0.14R_\oplus$ and $3.23\pm0.19R_\oplus$ 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 $c$ and $d$.(Abridged)
description: 21 pages, 12 figures. Accepted for publication on A&amp;A