TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf

Hawthorn, Faith; Bayliss, Daniel; Wilson, Thomas G; Bonfanti, Andrea; Adibekyan, Vardan; Alibert, Yann; Sousa, Sérgio G; Collins, Karen A; Bryant, Edward M; Osborn, Ares; Armstrong, David J; Abe, Lyu; Acton, Jack S; Addison, Brett C; Agabi, Karim; Alonso, Roi; Alves, Douglas R; Anglada-Escudé, Guillem; Bárczy, Tamas; Barclay, Thomas; Barrado, David; Barros, Susana C C; Baumjohann, Wolfgang; Bendjoya, Philippe; Benz, Willy; Bieryla, Allyson; Bonfils, Xavier; Bouchy, François; Brandeker, Alexis; Broeg, Christopher; Brown, David J A; Burleigh, Matthew R; Buttu, Marco; Cabrera, Juan; Caldwell, Douglas A; Casewell, Sarah L; Charbonneau, David; Charnoz, Sébastian; Cloutier, Ryan; Cameron, Andrew Collier; Collins, Kevin I; Conti, Dennis M; Crouzet, Nicolas; Czismadia, Szilárd; Davies, Melvyn B; Deleuil, Magali; Delgado-Mena, Elisa; Delrez, Laetitia; Demangeon, Olivier D S; Demory, Brice-Olivier; Dransfield, Georgina; Dumusque, Xavier; Egger, Jo; Ehrenreich, David; Eigmüller, Philipp; Erickson...

Abstract

We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and Sector 38. TOI-836 is a bright (T = 8.5?mag), high proper motion (~200?mas?yr-1), low metallicity ([Fe/H]˜-0.28) K-dwarf with a mass of 0.68 ± 0.05?M? and a radius of 0.67 ± 0.01?R?. We obtain photometric follow-up observations with a variety of facilities, and we use these data sets to determine that the inner planet, TOI-836?b, is a 1.70 ± 0.07?R? super-Earth in a 3.82-d orbit, placing it directly within the so-called ‘radius valley’. The outer planet, TOI-836?c, is a 2.59 ± 0.09?R? mini-Neptune in an 8.60-d orbit. Radial velocity measurements reveal that TOI-836?b has a mass of 4.5 ± 0.9?M?, while TOI-836?c has a mass of 9.6 ± 2.6?M?. Photometric observations show Transit Timing Variations (TTVs) on the order of 20?min for TOI-836?c, although there are no detectable TTVs for TOI-836?b. The TTVs of planet TOI-836?c may be caused by an undetected exterior planet.

Citation

Hawthorn, F., Bayliss, D., Wilson, T. G., Bonfanti, A., Adibekyan, V., Alibert, Y., Sousa, S. G., Collins, K. A., Bryant, E. M., Osborn, A., Armstrong, D. J., Abe, L., Acton, J. S., Addison, B. C., Agabi, K., Alonso, R., Alves, D. R., Anglada-Escudé, G., Bárczy, T., Barclay, T., …Zhang, H. (2023). TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf. Monthly Notices of the Royal Astronomical Society, 520(3), 3649 - 3668. https://doi.org/10.1093/mnras/stad306

• Journal Article Type: Article
• Acceptance Date: Jan 26, 2023
• Online Publication Date: Feb 9, 2023
• Publication Date: 2023-04
• Publicly Available Date: May 30, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 520
• Issue: 3
• Pages: 3649 - 3668
• DOI: https://doi.org/10.1093/mnras/stad306
• Keywords: techniques: photometrict; radial velocities; planets and satellites: detections; stars: individual: TOI-836 (TIC 440887364, GAIA EDR3 6230733559097425152)
• Public URL: https://keele-repository.worktribe.com/output/425714
• Publisher URL: https://academic.oup.com/mnras/article-abstract/520/3/3649/7033445?redirectedFrom=fulltext