2025MNRAS.544.2614E

Query : 2025MNRAS.544.2614E

2025MNRAS.544.2614E - Mon. Not. R. Astron. Soc., 544, 2614-2636 (2025/December-1)

An ultra-short period super-Earth and sub-Neptune spanning the Radius Valley orbiting the kinematic thick disc star TOI-2345.

ESCHEN Y.N.E., WILSON T.G., BONFANTI A., PERSSON C.M., SOUSA S.G., LENDL M., HEITZMANN A., SIMON A.E., OLOFSSON G., CASTRO-GONZALEZ A., EGGER J.A., FOSSATI L., MUSTILL A.J., OSBORN H.P., VIVIEN H.G., ALIBERT Y., ALONSO R., BARCZY T., BARRADO D., BARROS S.C.C., BAUMJOHANN W., BENZ W., BILLOT N., BORSATO L., BRANDEKER A., BROEG C., BUDER M., CALDWELL D.A., CAMERON A.C., CORREIA A.C.M., CSIZMADIA S., CUBILLOS P.E., DAVIES M.B., DELEUIL M., DELINE A., DEMANGEON O.D.S., DEMORY B.-O., DEREKAS A., EDWARDS B., EHRENREICH D., ERIKSON A., FARINATO J., FORTIER A., FRIDLUND M., GANDOLFI D., GAZEAS K., GILLON M., GOEKE R., GUDEL M., GUNTHER M.N., HASIBA J., HELLING C., ISAAK K.G., JENKINS J.M., KELLER T., KISS L.L., KITZMANN D., KORTH J., LAM K.W.F., LASKAR J., LECAVELIER DES ETANGS A., LELEU A., MAGRIN D., MAXTED P.F.L., MERIN B., MORDASINI C., NASCIMBENI V., OTTENSAMER R., PAGANO I., PALLE E., PETER G., PIAZZA D., PIOTTO G., POLLACCO D., QUELOZ D., RAGAZZONI R., RANDO N., RATTI F., RAUER H., RIBAS I., SANTOS N.C., SCANDARIATO G., SEGRANSAN D., SHPORER A., SMITH A.M.S., STALPORT M., SULIS S., SZABO G.M., UDRY S., ULMER-MOLL S., VAN GROOTEL V., VENTURINI J., VILLAVER E., WALTON N.A., WATANABE D., WOLF S. and ZIEGLER C.

Abstract (from CDS):

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 TOI-2345. 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 $1.504\substack{+0.047 -0.044}$ R$_{\oplus }$ and a mass of $3.49\pm 0.85$ M$_{\oplus }$; and TOI-2345 c to have a radius of $2.451\substack{+0.045 -0.046}$ R$_{\oplus }$ and a mass of $7.27\substack{+2.27 -2.45}$ M$_{\oplus }$. 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.

Abstract Copyright: © The Author(s) 2025. Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): techniques: photometric - techniques: radial velocities - planets and satellites: detection - planets and satellites: interiors - planets and satellites: individual: TOI-2345 b & c - stars: individual: TOI-2345

Simbad objects: 33

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Number of rows : 33
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME NCP reg 00 00 00 +90 00.0           ~ 216 0
2 TOI-178f Pl 00 29 12.3029193648 -30 27 13.466857032           ~ 15 0
3 TOI-178c Pl 00 29 12.3029193648 -30 27 13.466857032           ~ 29 0
4 TOI-178b Pl 00 29 12.3029193648 -30 27 13.466857032           ~ 29 0
5 WT 2353 PM* 00 29 12.3029193648 -30 27 13.466857032   13.05 11.95     ~ 102 0
6 HIP 8152c Pl? 01 44 50.3157312912 -18 24 03.266669448           ~ 7 0
7 HIP 8152b Pl? 01 44 50.3157312912 -18 24 03.266669448           ~ 7 0
8 BD-19 302 MS* 01 44 50.3157312912 -18 24 03.266669448   10.84 10.03     G5 35 0
9 HD 12572 MS* 02 03 37.0252967640 +21 16 51.112623468       8.8   G5 52 0
10 HD 12572b Pl 02 03 37.0252967640 +21 16 51.112623468           ~ 10 0
11 TOI-2345c Pl? 02 55 32.0952041424 -34 58 39.090713340           ~ 1 0
12 LP 942-63 PM* 02 55 32.0952041424 -34 58 39.090713340   12.40 11.48     ~ 14 0
13 TOI-2345b Pl? 02 55 32.0952041424 -34 58 39.090713340           ~ 1 0
14 HD 20329b Pl 03 16 42.6297956112 +15 39 26.012554056           ~ 13 0
15 G 6-3b Pl 03 22 02.3173727376 +17 14 23.881975296           ~ 4 0
16 K2-111 PM* 03 59 33.5381228011 +21 17 55.244066403   11.80 11.14 11.003   ~ 36 0
17 K2-111b Pl 03 59 33.5381228011 +21 17 55.244066403           ~ 28 1
18 HD 42813 MS* 06 12 13.9672271784 -14 39 00.061897248   10.32 9.47     K0V 51 0
19 K2-180b Pl 08 25 51.3437842728 +10 14 49.060473144           ~ 18 0
20 NAME L 248-27b Pl 10 26 59.4940030876 -52 28 09.944352049           ~ 26 0
21 TOI-669b Pl 10 35 36.1582362336 -05 10 54.063559020           ~ 8 0
22 NAME NGP reg 12 51 26.275 +27 07 41.70           ~ 1274 0
23 BD-05 3763b Pl 13 47 23.4438244137 -06 08 12.729406281           ~ 22 0
24 * nu.02 Lup c Pl 15 21 48.1499105161 -48 19 03.469906910           ~ 33 1
25 * nu.02 Lup d Pl 15 21 48.1499105161 -48 19 03.469906910           ~ 24 1
26 * nu.02 Lup PM* 15 21 48.1499105161 -48 19 03.469906910 6.35 6.30 5.65     G2-V 354 1
27 * nu.02 Lup b Pl 15 21 48.1499105161 -48 19 03.469906910           ~ 49 1
28 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
29 Kepler-10c Pl 19 02 43.0613892904 +50 14 28.701617339           ~ 135 1
30 Kepler-10 Em* 19 02 43.0613892904 +50 14 28.701617339       11.00   G2V 238 1
31 Kepler-10b Pl 19 02 43.0613892904 +50 14 28.701617339           ~ 322 1
32 NAME L 210-70b Pl 20 27 42.0813992356 -56 27 25.151894071           ~ 68 0
33 * 51 Peg PM* 22 57 27.9804852576 +20 46 07.797040104 6.39 6.16 5.46 4.97 4.61 G2IV 1216 1

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