2024MNRAS.534.3744N

Query : 2024MNRAS.534.3744N

2024MNRAS.534.3744N - Mon. Not. R. Astron. Soc., 534, 3744-3760 (2024/November-2)

HD 21520 b: a warm sub-Neptune transiting a bright G dwarf.

NIES M., MIRELES I., BOUCHY F., DRAGOMIR D., NICHOLSON B.A., EISNER N.L., SOUSA S.G., COLLINS K.A., HOWELL S.B., ZIEGLER C., HELLIER C., ADDISON B., BALLARD S., BOWLER B.P., BRICENO C., CLARK C.A., CONTI D.M., DUMUSQUE X., EDWARDS B., GNILKA C.L., HOBSON M., HORNER J., KANE S.R., KIELKOPF J., LAVIE B., LAW N., LENDL M., LITTLEFIELD C., LIU H., MANN A.W., MENGEL M.W., ODDO D., OKUMURA J., PALLE E., PLAVCHAN P., PSARIDI A., SANTOS N.C., SCHWARZ R.P., SHPORER A., WITTENMYER R.A., WRIGHT D.J., ZHANG H., WATANABE D., MEDINA J.V., VILLASENOR J., TING E.B., CHRISTIANSEN J.L., WINN J.N., STASSUN K.G., SEAGER S., LATHAM D.W. and RICKER G.R.

Abstract (from CDS):

We report the discovery and validation of HD 21520 b, a transiting planet found with Transiting Exoplanet Survey Satellite and orbiting a bright G dwarf (V = 9.2, $T_{\rm eff} = 5871 \pm 62$ K, $R_{\star } = 1.04\pm 0.02\, {\rm R}_{\odot }$). HD 21520 b was originally alerted as a system (TOI-4320) consisting of two planet candidates with periods of 703.6 and 46.4 d. However, our analysis supports instead a single-planet system with an orbital period of $25.1292\pm 0.0001$ d and radius of $2.70 \pm 0.09\, {\rm R}_{{\oplus }}$. Three full transits in sectors 4, 30, and 31 match this period and have transit depths and durations in agreement with each other, as does a partial transit in sector 3. We also observe transits using CHEOPS and LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of any nearby companions, and MINERVA-Australis and CORALIE radial velocities rule out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial velocities to obtain a tentative mass measurement of $7.9^{+3.2}_{-3.0}\, {\rm M}_{{\oplus }}$, with a 3$\sigma$ upper limit of 17.7 ${\rm M}_{{\oplus }}$. Due to the bright nature of its host and likely significant gas envelope of the planet, HD 21520b is a promising candidate for further mass measurements and for atmospheric characterization.

Abstract Copyright: © 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): techniques: photometric - techniques: radial velocities - planets and satellites: composition - planets and satellites: individual: (HD 21520)

Simbad objects: 9

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Number of rows : 9
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 HD 21520b Pl 03 26 33.6859950408 -43 36 48.838786668           ~ 2 0
2 HD 21520 * 03 26 33.6859950408 -43 36 48.838786668   9.78 9.15     G2/3V 24 0
3 HD 22946d Pl 03 39 16.7617744728 -42 45 45.185938812           ~ 9 0
4 HD 56414b Pl 07 11 22.4864052768 -68 50 00.569254056           ~ 5 0
5 HD 63433c Pl 07 49 55.0606576176 +27 21 47.457467316           ~ 65 0
6 HD 95338b Pl 10 59 26.3040013933 -56 37 22.947342987           ~ 22 0
7 BD+46 2726b Pl 19 34 43.0022454096 +46 51 09.938179044           ~ 55 0
8 HD 191939d Pl 20 08 05.7551464176 +66 51 02.076637068           ~ 14 0
9 HD 191939c Pl 20 08 05.7551464176 +66 51 02.076637068           ~ 23 0

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