2020AJ....160...22C

Query : 2020AJ....160...22C

2020AJ....160...22C - Astron. J., 160, 22-22 (2020/July-0)

TOI-1235 b: a keystone super-earth for testing radius valley emergence models around early M dwarfs.

CLOUTIER R., RODRIGUEZ J.E., IRWIN J., CHARBONNEAU D., STASSUN K.G., MORTIER A., LATHAM D.W., ISAACSON H., HOWARD A.W., UDRY S., WILSON T.G., WATSON C.A., PINAMONTI M., LIENHARD F., GIACOBBE P., GUERRA P., COLLINS K.A., BEIRYLA A., ESQUERDO G.A., MATTHEWS E., MATSON R.A., HOWELL S.B., FURLAN E., CROSSFIELD I.J.M., WINTERS J.G., NAVA C., MENT K., LOPEZ E.D., RICKER G., VANDERSPEK R., SEAGER S., JENKINS J.M., TING E.B., TENENBAUM P., SOZZETTI A., SHA L., SEGRANSAN D., SCHLIEDER J.E., SASSELOV D., ROY A., ROBERTSON P., RICE K., PORETTI E., PIOTTO G., PHILLIPS D., PEPPER J., PEPE F., MOLINARI E., MOCNIK T., MICELA G., MAYOR M., MARTINEZ FIORENZANO A.F., MALLIA F., LUBIN J., LOVIS C., LOPEZ-MORALES M., KOSIAREK M.R., KIELKOPF J.F., KANE S.R., JENSEN E.L.N., ISOPI G., HUBER D., HILL M.L., HARUTYUNYAN A., GONZALES E., GIACALONE S., GHEDINA A., ERCOLINO A., DUMUSQUE X., DRESSING C.D., DAMASSO M., DALBA P.A., COSENTINO R., CONTI D.M., COLON K.D., COLLINS K.I., CAMERON A.C., CIARDI D., CHRISTIANSEN J., CHONTOS A., CECCONI M., CALDWELL D.A., BURKE C., BUCHHAVE L., BEICHMAN C., BEHMARD A., BEARD C. and MURPHY J.M.A.

Abstract (from CDS):

Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/nonrocky transition in period-radius space. Here we present the confirmation of TOI-1235 b (P = 3.44 days, rp=1.738–0.076+0.087R⊕), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/nonrocky transition around early M dwarfs (Rs = 0.630 ± 0.015 R☉, Ms = 0.640 ± 0.016 M☉). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial velocities (RVs) from HARPS-N and HIRES. We measure a planet mass of 6.91–0.85+0.75M⊕, which implies an iron core mass fraction of 20–12+15% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like, and we constrain an H/He envelope mass fraction to be <0.5% at 90% confidence. Our results are consistent with model predictions from thermally driven atmospheric mass loss but not with gas-poor formation, suggesting that the former class of processes remains efficient at sculpting close-in planets around early M dwarfs. Our RV analysis also reveals a strong periodicity close to the first harmonic of the photometrically determined stellar rotation period that we treat as stellar activity, despite other lines of evidence favoring a planetary origin (P=21.8–0.8+0.9 days, mpsini=13.0–5.3+3.8M⊕) that cannot be firmly ruled out by our data.

Abstract Copyright: © 2020. The American Astronomical Society. All rights reserved.

Journal keyword(s): Radial velocity - M dwarf stars - Transit photometry - Exoplanet formation - Exoplanet structure

VizieR on-line data: <Available at CDS (J/AJ/160/22): table2.dat fig3.dat>

Simbad objects: 15

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Number of rows : 15
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 G 268-38 PM* 00 44 59.3309137511 -15 16 17.542839990     14.150 13.801   M4.5V 142 0
2 NAME G 268-38b Pl 00 44 59.3309137511 -15 16 17.542839990           ~ 180 0
3 LP 424-4 PM* 07 59 05.8395356736 +15 23 29.236065000   13.5   11.934   M2.0V 125 1
4 L 98-59 PM* 08 18 07.6214406393 -68 18 46.805365587   13.22 11.685 11.294   M3V 92 0
5 L 678-39 EB* 09 36 01.6372169407 -21 39 38.877606712 13.647 12.48 10.906 9.858 8.577 M2.5V 161 0
6 G 235-55 PM* 10 07 59.3323366603 +69 14 45.699941607   16.08 14.33 13.12 11.54 M4 26 0
7 LSPM J1008+6916 PM* 10 08 51.8069885952 +69 16 35.560317504       11.065   M0.5V 31 0
8 LSPM J1008+6916b Pl 10 08 51.8069885952 +69 16 35.560317504           ~ 33 0
9 L 320-124 PM* 10 14 51.7786855411 -47 09 24.192778106       13.067   M4 126 0
10 G 162-44 PM* 10 18 35.1372361341 -11 43 00.243355403   14.68 13.14 12.84   M4.0 56 0
11 K2-18 PM* 11 30 14.5177445592 +07 35 18.255348492   15.01 13.50 13.24   dM2.5 97 0
12 G 139-21 PM* 17 15 18.9339850845 +04 57 50.066612336       14.394   M4.5V 326 1
13 NAME Barnard's star BY* 17 57 48.4984700685 +04 41 36.113879676 12.497 11.24 9.511 8.298 6.741 M4V 815 2
14 L 210-70 PM* 20 27 42.0813992356 -56 27 25.151894071       11.83   M2.5V 42 0
15 CD-60 8051 PM* 23 20 07.5245143451 -60 03 54.644648069   12.45 11.02 10.584   M2V 45 0

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