| Contributors: |
Lund University, Faculty of Science, Department of Physics, Astrophysics, Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Astrofysik, Originator, Lund University, Faculty of Science, Centre for Mathematical Sciences, Mathematics (Faculty of Sciences), Lunds universitet, Naturvetenskapliga fakulteten, Matematikcentrum, Matematik (naturvetenskapliga fakulteten), Originator, Lund University, Faculty of Engineering, LTH, LTH Profile areas, LTH Profile Area: AI and Digitalization, Lunds universitet, Lunds Tekniska Högskola, LTH profilområden, LTH profilområde: AI och digitalisering, Originator, Lund University, Profile areas and other strong research environments, Lund University Profile areas, LU Profile Area: Natural and Artificial Cognition, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Lunds universitets profilområden, LU profilområde: Naturlig och artificiell kognition, Originator, Lund University, Profile areas and other strong research environments, Strategic research areas (SRA), eSSENCE: The e-Science Collaboration, Lunds universitet, Profilområden och andra starka forskningsmiljöer, Strategiska forskningsområden (SFO), eSSENCE: The e-Science Collaboration, Originator |
| Description: |
A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Therefore, this potential vital link needs testing by characterizing exoplanets around chemically-diverse stars. We present the discovery of two planets orbiting the metal-poor, kinematic thick-disc K-dwarf TOI2345. TOI-2345 b is a super-Earth with a period of 1.05 d and TOI-2345 c is a sub-Neptune with a period of 21 d. In addition to the target being observed in four TESS sectors, we obtained five CHEOPS visits and 26 radial velocities from HARPS. By conducting a joint analysis of all the data, we find TOI-2345 b to have a radius of 1.504+0.047−0.044R⊕ and a mass of 3.49 ± 0.85 M⊕; and TOI-2345 c to have a radius of 2.451+0.045−0.046R⊕ and a mass of 7.27+2.27−2.45 M⊕. To explore chemical links between these planets and their host star, we model their interior structures newly accounting for devolatized stellar abundances. TOI-2345 adds to the limited sample of well-characterized planetary systems around thick disc stars. This system challenges theories of formation and populations of planets around thick disc stars with its Ultra-Short Period super-Earth and the wide period distribution of these two planets spanning the radius valley |