2022A&A...666A.184P


Query : 2022A&A...666A.184P

2022A&A...666A.184P - Astronomy and Astrophysics, volume 666A, 184 (2022/10-1)

TOI-2196 b: Rare planet in the hot Neptune desert transiting a G-type star.

PERSSON C.M., GEORGIEVA I.Y., GANDOLFI D., ACUNA L., AGUICHINE A., MURESAN A., GUENTHER E., LIVINGSTON J., COLLINS K.A., DAI F., FRIDLUND M., GOFFO E., JENKINS J.S., KABATH P., KORTH J., LEVINE A.M., SERRANO L.M., VINES J., BARRAGAN O., CARLEO I., COLON K.D., COCHRAN W.D., CHRISTIANSEN J.L., DEEG H.J., DELEUIL M., DRAGOMIR D., ESPOSITO M., GAN T., GRZIWA S., HATZES A.P., HESSE K., HORNE K., JENKINS J.M., KIELKOPF J.F., KLAGYIVIK P., LAM K.W.F., LATHAM D.W., LUQUE R., ORELL-MIQUEL J., MORTIER A., MOUSIS O., NARITA N., OSBORNE H.L.M., PALLE E., PAPINI R., RICKER G.R., SCHMERLING H., SEAGER S., STASSUN K.G., VAN EYLEN V., VANDERSPEK R., WANG G., WINN J.N., WOHLER B., ZAMBELLI R. and ZIEGLER C.

Abstract (from CDS):

The hot Neptune desert is a region hosting a small number of short-period Neptunes in the radius-instellation diagram. Highly irradiated planets are usually either small (R ≲ 2 R) and rocky or they are gas giants with radii of ≳1 RJ. Here, we report on the intermediate-sized planet TOI-2196 b (TIC 372172128.01) on a 1.2 day orbit around a G-type star (V = 12.0, [Fe/H] = 0.14 dex) discovered by the Transiting Exoplanet Survey Satellite in sector 27. We collected 41 radial velocity measurements with the HARPS spectrograph to confirm the planetary nature of the transit signal and to determine the mass. The radius of TOI-2196 b is 3.51 ± 0.15 R, which, combined with the mass of 26.0 ± 1.3 M, results in a bulk density of 3.31–0.43+0.51 g cm–3. Hence, the radius implies that this planet is a sub-Neptune, although the density is twice than that of Neptune. A significant trend in the HARPS radial velocity measurements points to the presence of a distant companion with a lower limit on the period and mass of 220 days and 0.65 MJ, respectively, assuming zero eccentricity. The short period of planet b implies a high equilibrium temperature of 1860 ± 20 K, for zero albedo and isotropic emission. This places the planet in the hot Neptune desert, joining a group of very few planets in this parameter space discovered in recent years. These planets suggest that the hot Neptune desert may be divided in two parts for planets with equilibrium temperatures of ≳1800 K: a hot sub-Neptune desert devoid of planets with radii of ≈ 1.8-3 R and a sub-Jovian desert for radii of ≈5-12 R. More planets in this parameter space are needed to further investigate this finding. Planetary interior structure models of TOI-2196 b are consistent with a H/He atmosphere mass fraction between 0.4% and 3%, with a mean value of 0.7% on top of a rocky interior. We estimated the amount of mass this planet might have lost at a young age and we find that while the mass loss could have been significant, the planet had not changed in terms of character: it was born as a small volatile-rich planet and it remains one at present.

Abstract Copyright: © C. M. Persson et al. 2022

Journal keyword(s): planets and satellites: composition - planetary systems - planets and satellites: detection - planets and satellites: individual: TOI-2196 - techniques: photometric - techniques: radial velocities

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 TOI-849b Pl 01 54 51.7040408544 -29 25 18.468394788           ~ 41 0
2 K2-100b Pl 08 38 24.3002838928 +20 06 21.828057218           ~ 67 0
3 K2-278b Pl 13 33 12.4281519480 -14 30 14.604163236           ~ 6 0
4 Kepler-644b Pl 19 41 54.1746080448 +43 29 35.273786640           ~ 17 0
5 TOI-2196b Pl 20 49 21.5673706512 -70 29 05.947781316           ~ 7 0
6 TOI-2196 * 20 49 21.5673706512 -70 29 05.947781316   13.01 12.30 11.846   ~ 4 0
7 DENIS J204921.6-702918 * 20 49 21.7709382613 -70 29 18.655438861         18.189 ~ 1 0
8 CD-38 15670b Pl 23 54 40.2073116552 -37 37 40.524416508           ~ 46 0

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