TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data

• Published in: arXiv.org 2021-08
• Main Authors: Kostov, Veselin B, Powell, Brian P, Orosz, Jerome A, Welsh, William F, Cochran, William, Collins, Karen A, Endl, Michael, Hellier, Coel, Latham, David W, MacQueen, Phillip, Pepper, Joshua, Quarles, Billy, Sairam, Lalitha, Torres, Guillermo, Wilson, Robert F, Bergeron, Serge, Boyce, Pat, Bieryla, Allyson, Buchheim, Robert, Caleb Ben Christiansen, Ciardi, David R, Collins, Kevin I, Conti, Dennis M, Dixon, Scott, Guerra, Pere, Haghighipour, Nader, Herman, Jeffrey, Hintz, Eric G, Howard, Ward S, Jensen, Eric L N, Kielkopf, John F, Kruse, Ethan, Law, Nicholas M, Martin, David, Maxted, Pierre F L, Montet, Benjamin T, Murgas, Felipe, Nelson, Matt, Olmschenk, Greg, Otero, Sebastian, Quimby, Robert, Richmond, Michael, Schwarz, Richard P, Shporer, Avi, Stassun, Keivan G, Stephens, Denise C, Amaury H M J Triaud, Ulowetz, Joe, Walter, Bradley S, Wiley, Edward, Wood, David, Mitchell Yenawine, Agol, Eric, Barclay, Thomas, Beatty, Thomas G, Boisse, Isabelle, Caldwell, Douglas A, Christiansen, Jessie, Colon, Knicole D, Deleuil, Magali, Doyle, Laurance, Fabrycky, Daniel, Fausnaugh, Michael, Furesz, Gabor, Gilbert, Emily A, Hebrard, Guillaume, James, David J, Jenkins, Jon, Kane, Stephen R, Kidwell, Richard C, Kopparapu, Ravi, Li, Gongjie, Lissauer, Jack J, Lund, Michael B, Majewski, Steve, Mazeh, Tsevi, Quinn, Samuel N, Quintana, Elisa, Ricker, George, Rodriguez, Joseph E, Rowe, Jason, Santerne, Alexander, Schlieder, Joshua, Seager, Sara, Standing, Matthew R, Stevens, Daniel J, Ting, Eric B, Vanderspek, Roland, Winn, Joshua N
• Format: Article
• Language: English
• Subjects: Binary stars; Eccentricity; Extrasolar planets; Orbits
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2105.08614

We report the first discovery of a transiting circumbinary planet detected from a single sector of TESS data. During Sector 21, the planet TIC 172900988b transited the primary star and then 5 days later it transited the secondary star. The binary is itself eclipsing, with a period of P = 19.7 days and an eccentricity of e = 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of M1 = 1.2384 +/- 0.0007 MSun and R1 = 1.3827 +/- 0.0016 RSun for the primary and M2 = 1.2019 +/- 0.0007 MSun and R2 = 1.3124 +/- 0.0012 RSun for the secondary. The radius of the planet is R3 = 11.25 +/- 0.44 REarth (1.004 +/- 0.039 RJup). The planet's mass and orbital properties are not uniquely determined - there are six solutions with nearly equal likelihood. Specifically, we find that the planet's mass is in the range of 824 < M3 < 981 MEarth (2.65 < M3 < 3.09 MJup), its orbital period could be 188.8, 190.4, 194.0, 199.0, 200.4, or 204.1 days, and the eccentricity is between 0.02 and 0.09. At a V = 10.141 mag, the system is accessible for high-resolution spectroscopic observations, e.g. Rossiter-McLaughlin effect and transit spectroscopy.