TOI-969: a late-K dwarf with a hot mini-Neptune in the desert and an eccentric cold Jupiter

DOI: 
10.1051/0004-6361/202243879
Publication date: 
15/01/2023
Main author: 
Lillo-Box, J.
IAA authors: 
Luque, R.
Authors: 
Lillo-Box, J.;Gandolfi, D.;Armstrong, D. J.;Collins, K. A.;Nielsen, L. D.;Luque, R.;Korth, J.;Sousa, S. G.;Quinn, S. N.;Acuña, L.;Howell, S. B.;Morello, G.;Hellier, C.;Giacalone, S.;Hoyer, S.;Stassun, K.;Palle, E.;Aguichine, A.;Mousis, O.;Adibekyan, V.;Azevedo Silva, T.;Barrado, D.;Deleuil, M.;Eastman, J. D.;Fukui, A.;Hawthorn, F.;Irwin, J. M.;Jenkins, J. M.;Latham, D. W.;Muresan, A.;Narita, N.;Persson, C. M.;Santerne, A.;Santos, N. C.;Savel, A. B.;Osborn, H. P.;Teske, J.;Wheatley, P. J.;Winn, J. N.;Barros, S. C. C.;Butler, R. P.;Caldwell, D. A.;Charbonneau, D.;Cloutier, R.;Crane, J. D.;Demangeon, O. D. S.;Díaz, R. F.;Dumusque, X.;Esposito, M.;Falk, B.;Gill, H.;Hojjatpanah, S.;Kreidberg, L.;Mireles, I.;Osborn, A.;Ricker, G. R.;Rodriguez, J. E.;Schwarz, R. P.;Seager, S.;Serrano Bell, J.;Shectman, S. A.;Shporer, A.;Vezie, M.;Wang, S. X.;Zhou, G.
Journal: 
Astronomy and Astrophysics
Publication type: 
Article
Volume: 
669
Pages: 
A109
Abstract: 
Context. The current architecture of a given multi-planetary system is a key fingerprint of its past formation and dynamical evolution history. Long-term follow-up observations are key to complete their picture. <BR /> Aims: In this paper, we focus on the confirmation and characterization of the components of the TOI-969 planetary system, where TESS detected a Neptune-size planet candidate in a very close-in orbit around a late K-dwarf star. <BR /> Methods: We use a set of precise radial velocity observations from HARPS, PFS, and CORALIE instruments covering more than two years in combination with the TESS photometric light curve and other ground-based follow-up observations to confirm and characterize the components of this planetary system. <BR /> Results: We find that TOI-969 b is a transiting close-in (P<SUB>b</SUB> ~ 1.82 days) mini-Neptune planet (m<SUB>b</SUB> = 9.1<SUB>−1.0</SUB><SUP>+1.1</SUP> M<SUB>⊕</SUB>, R<SUB>b</SUB> = 2.765<SUB>−0.097</SUB><SUP>+0.088</SUP> R<SUB>⊕</SUB>), placing it on the lower boundary of the hot-Neptune desert (T<SUB>eq,b</SUB> = 941 ± 31 K). The analysis of its internal structure shows that TOI-969 b is a volatile-rich planet, suggesting it underwent an inward migration. The radial velocity model also favors the presence of a second massive body in the system, TOI-969 c, with a long period of P<SUB>c</SUB> = 1700<SUB>−280</SUB><SUP>+290</SUP> days, a minimum mass of m<SUB>c</SUB> sin i<SUB>c</SUB> = 11.3<SUB>−0.9</SUB><SUP>+1.1</SUP> M<SUB>Jup</SUB>, and a highly eccentric orbit of e<SUB>c</SUB> = 0.628<SUB>−0.036</SUB><SUP>+0.043</SUP>. <BR /> Conclusions: The TOI-969 planetary system is one of the few around K-dwarfs known to have this extended configuration going from a very close-in planet to a wide-separation gaseous giant. TOI-969 b has a transmission spectroscopy metric of 93 and orbits a moderately bright (G = 11.3 mag) star, making it an excellent target for atmospheric studies. The architecture of this planetary system can also provide valuable information about migration and formation of planetary systems. <P />Full Tables A.1-A.4 is only available at the CDS via anonymous ftp to <A href="https://cdsarc.cds.unistra.fr/">cdsarc.cds.unistra.fr</A> (ftp://130.79.128.5) or via <A href="https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/669/A109">https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/669/A109</A>
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023A&A...669A.109L/abstract
ADS Bibcode: 
2023A&A...669A.109L
Keywords: 
planets and satellites: detection;planets and satellites: fundamental parameters;planets and satellites: composition;techniques: radial velocities;techniques: photometric;stars: individual: TOI-969;Astrophysics - Earth and Planetary Astrophysics