The TESS-Keck Survey. XI. Mass Measurements for Four Transiting sub-Neptunes orbiting K dwarf TOI-1246
Creators: name: Turtelboom, Emma V.
name: Weiss, Lauren M.
name: Dressing, Courtney D.
name: Nowak, Grzegorz
name: Pallé, Enric
name: Beard, Corey
name: Blunt, Sarah
name: Brinkman, Casey
name: Chontos, Ashley
name: Claytor, Zachary R.
name: Dai, Fei
name: Dalba, Paul A.
name: Giacalone, Steven
name: Gonzales, Erica
name: Harada, Caleb K.
name: Hill, Michelle L.
name: Holcomb, Rae
name: Korth, Judith
name: Lubin, Jack
name: Masseron, Thomas
name: MacDougall, Mason
name: Mayo, Andrew W.
name: Močnik, Teo
name: Murphy, Joseph M. Akana
name: Polanski, Alex S.
name: Rice, Malena
name: Rubenzahl, Ryan A.
name: Scarsdale, Nicholas
name: Stassun, Keivan G.
name: Tyler, Dakotah B.
name: Van Zandt, Judah
name: Crossfield, Ian J. M.
name: Deeg, Hans J.
name: Fulton, Benjamin
name: Gandolfi, Davide
name: Howard, Andrew W.
name: Huber, Dan
name: Isaacson, Howard
name: Kane, Stephen R.
name: Lam, Kristine W. F.
name: Luque, Rafael
name: Martín, Eduardo L.
name: Morello, Giuseppe
name: Orell-Miquel, Jaume
name: Petigura, Erik A.
name: Robertson, Paul
name: Roy, Arpita
name: Van Eylen, Vincent
name: Baker, David
name: Belinski, Alexander A.
name: Bieryla, Allyson
name: Ciardi, David R.
name: Collins, Karen A.
name: Cutting, Neil
name: Della-Rose, Devin J.
name: Ellingsen, Taylor B.
name: Furlan, E.
name: Gan, Tianjun
name: Gnilka, Crystal L.
name: Guerra, Pere
name: Howell, Steve B.
name: Jimenez, Mary
name: Latham, David W.
name: Larivière, Maude
name: Lester, Kathryn V.
name: Lillo-Box, Jorge
name: Luker, Lindy
name: Mann, Christopher R.
name: Plavchan, Peter P.
name: Safonov, Boris
name: Skinner, Brett
name: Strakhov, Ivan A.
name: Wittrock, Justin M.
name: Caldwell, Douglas A.
name: Essack, Zahra
name: Jenkins, Jon M.
name: Quintana, Elisa V.
name: Ricker, George R.
name: Vanderspek, Roland
name: Seager, S.
name: Winn, Joshua N.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Multi-planet systems are valuable arenas for investigating exoplanet architectures and comparing planetary siblings. TOI-1246 is one such system, with a moderately bright K dwarf ($\rm{V=11.6,~K=9.9}$) and four transiting sub-Neptunes identified by TESS with orbital periods of $4.31~\rm{d},~5.90~\rm{d},~18.66~\rm{d}$, and $~37.92~\rm{d}$. We collected 130 radial velocity observations with Keck/HIRES and TNG/HARPS-N to measure planet masses. We refit the 14 sectors of TESS photometry to refine planet radii ($\rm{2.97 \pm 0.06~R_\oplus},\rm{2.47 \pm 0.08~R_\oplus}, \rm{3.46 \pm 0.09~R_\oplus}$, $\rm{3.72 \pm 0.16~R_\oplus}$), and confirm the four planets. We find that TOI-1246 e is substantially more massive than the three inner planets ($\rm{8.1 \pm 1.1 M_\oplus}$, $\rm{8.8 \pm 1.2 M_\oplus}$, $\rm{5.3 \pm 1.7 M_\oplus}$, $\rm{14.8 \pm 2.3 M_\oplus}$). The two outer planets, TOI-1246 d and TOI-1246 e, lie near to the 2:1 resonance ($\rm{P_{e}/P_{d}=2.03}$) and exhibit transit timing variations. TOI-1246 is one of the brightest four-planet systems, making it amenable for continued observations. It is one of only six systems with measured masses and radii for all four transiting planets. The planet densities range from $\rm{0.70 \pm 0.24}$ to $3.21 \pm 0.44 \rm{g/cm^3}$, implying a range of bulk and atmospheric compositions. We also report a fifth planet candidate found in the RV data with a minimum mass of 25.6 $\pm$ 3.6 $\rm{M_\oplus}$. This planet candidate is exterior to TOI-1246 e with a candidate period of 93.8 d, and we discuss the implications if it is confirmed to be planetary in nature.
description: Accepted at The Astronomical Journal; 33 pages, 10 figures