TOI-757 b: an eccentric transiting mini-Neptune on a 17.5-d orbit
Date Issued
2024
Author(s)
Alqasim, A.
•
Grieves, N.
•
Rosário, N. M.
•
Gandolfi, D.
•
Livingston, J. H.
•
Sousa, S.
•
Collins, K. A.
•
Teske, J. K.
•
Fridlund, M.
•
Egger, J. A.
•
Cabrera, J.
•
Hellier, C.
•
•
Van Eylen, V.
•
Bouchy, F.
•
Oelkers, R. J.
•
Srdoc, G.
•
Shectman, S.
•
Günther, M.
•
Goffo, E.
•
Wilson, T.
•
Serrano, L. M.
•
Brandeker, A.
•
Wang, S. X.
•
Heitzmann, A.
•
Bonfanti, A.
•
Fossati, L.
•
Alibert, Y.
•
Delrez, L.
•
Sefako, R.
•
Barros, S.
•
Collins, K. I.
•
Demangeon, O. D. S.
•
Albrecht, S. H.
•
Alonso, R.
•
Asquier, J.
•
Barczy, T.
•
Barrado, D.
•
Baumjohann, W.
•
Beck, T.
•
Benz, W.
•
Billot, N.
•
•
Broeg, C.
•
Bryant, E. M.
•
Butler, R. P.
•
Cochran, W. D.
•
Cameron, A. Collier
•
Correia, A. C. M.
•
Crane, J. D.
•
Csizmadia, Sz
•
Cubillos, P. E.
•
Davies, M. B.
•
Daylan, T.
•
Deleuil, M.
•
Deline, A.
•
Demory, B. -O.
•
Derekas, A.
•
Edwards, B.
•
Ehrenreich, D.
•
Erikson, A.
•
Essack, Z.
•
Fortier, A.
•
Gazeas, K.
•
Gillon, M.
•
Gudel, M.
•
Hasiba, J.
•
Hatzes, A. P.
•
Helling, Ch
•
Hirano, T.
•
Howell, S. B.
•
Hoyer, S.
•
Isaak, K. G.
•
Jenkins, J. M.
•
Kanodia, S.
•
Kiss, L. L.
•
Korth, J.
•
Lam, K. W. F.
•
Laskar, J.
•
Etangs, A. Lecavelier des
•
Lendl, M.
•
Lund, M. B.
•
Luque, R.
•
Mann, A. W.
•
•
Maxted, P. F. L.
•
Mordasini, C.
•
Narita, N.
•
•
Nowak, G.
•
Olofsson, G.
•
Osborn, H. P.
•
Osborne, H. L. M.
•
Osip, D.
•
Ottensamer, R.
•
•
Palle, E.
•
Peter, G.
•
Piotto, G.
•
Pollacco, D.
•
Queloz, D.
•
•
Rando, N.
•
Rauer, H.
•
Redfield, S.
•
Ribas, I.
•
Rice, M.
•
Ricker, G. R.
•
Rieder, M.
•
Salmon, S.
•
Santos, N. C.
•
•
Seager, S.
•
Segransan, D.
•
Shporer, A.
•
Simon, A. E.
•
Smith, A. M. S.
•
Stalport, M.
•
Szabo, Gy M.
•
Thompson, I.
•
Twicken, J. D.
•
Udry, S.
•
Vanderspek, R.
•
Van Grootel, V.
•
Venturini, J.
•
Villaver, E.
•
Villaseñor, J.
•
•
Walter, I.
•
Walton, N. A.
•
Winn, J. N.
•
Yee, S. W.
Abstract
We report the spectroscopic confirmation and fundamental properties of TOI$-$757 b, a mini$-$Neptune on a 17.5$-$d orbit transiting a bright star ($V\, =\, 9.7$ mag) discovered by the TESS mission. We acquired high$-$precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space$-$borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground$-$based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI$-$757 b has a radius of $R_{\mathrm{p}} = 2.5 \pm 0.1 R_{\oplus }$ and a mass of $M_{\mathrm{p}} = 10.5^{+2.2}_{-2.1} M_{\oplus }$, implying a bulk density of $\rho _{\text{p}} = 3.6 \pm 0.8$ g cm$^{-3}$. Our internal composition modelling was unable to constrain the composition of TOI$-$757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with e = 0.39$^{+0.08}_{-0.07}$, making it one of the very few highly eccentric planets among precisely characterized mini$-$Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI$-$757 b's formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star$-$star interactions during the earlier epoch of the Galactic disc formation, given the low metallicity and older age of TOI$-$757.
Volume
533
Issue
1
Start page
1
Issn Identifier
0035-8711
Ads BibCode
2024MNRAS.533....1A
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
stae1767.pdf
Description
PDF editoriale
Size
6.35 MB
Format
Adobe PDF
Checksum (MD5)
16b86614080ee274786aa961de79dc5f