2025MNRAS.536.2046Y

Query : 2025MNRAS.536.2046Y

2025MNRAS.536.2046Y - Mon. Not. R. Astron. Soc., 536, 2046-2063 (2025/January-3)

A possible misaligned orbit for the young planet AU Mic c.

YU H., GARAI Z., CRETIGNIER M., SZABO G.M., AIGRAIN S., GANDOLFI D., BRYANT E.M., CORREIA A.C.M., KLEIN B., BRANDEKER A., OWEN J.E., GUNTHER M.N., WINN J.N., HEITZMANN A., CEGLA H.M., WILSON T.G., GILL S., KRISKOVICS L., BARRAGAN O., BOLDOG A., NIELSEN L.D., BILLOT N., LAFARGA M., MEECH A., ALIBERT Y., ALONSO R., BARCZY T., BARRADO D., BARROS S.C.C., BAUMJOHANN W., BAYLISS D., BENZ W., BERGOMI M., BORSATO L., BROEG C., CAMERON A.C., CSIZMADIA S., CUBILLOS P.E., DAVIES M.B., DELEUIL M., DELINE A., DEMANGEON O.D.S., DEMORY B.-O., DEREKAS A., DOYLE L., EDWARDS B., EGGER J.A., EHRENREICH D., ERIKSON A., FORTIER A., FOSSATI L., FRIDLUND M., GAZEAS K., GILLON M., GUDEL M., HELLING C., ISAAK K.G., KISS L.L., KORTH J., LAM K.W.F., LASKAR J., LECAVELIER DES ETANGS A., LENDL M., MAGRIN D., MAXTED P.F.L., McCORMAC J., MERIN B., MORDASINI C., NASCIMBENI V., O'BRIEN S.M., OLOFSSON G., OTTENSAMER R., PAGANO I., PALLE E., PETER G., PIAZZA D., PIOTTO G., POLLACCO D., QUELOZ D., RAGAZZONI R., RANDO N., RAUER H., RIBAS I., SANTOS N.C., SCANDARIATO G., SEGRANSAN D., SIMON A.E., SMITH A.M.S., SOUSA S.G., SOUTHWORTH R., STALPORT M., STEINBERGER M., SULIS S., UDRY S., ULMER B., ULMER-MOLL S., VAN GROOTEL V., VENTURINI J., VILLAVER E., WALTON N.A. and WHEATLEY P.J.

Abstract (from CDS):

The AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter-McLaughlin effect for the warm sub-Neptune AU Mic c, using two transits observed simultaneously with the European Southern Observatory's (ESO's) Very Large Telescope (VLT)/Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO), CHaracterising ExOPlanet Satellite (CHEOPS), and Next-Generation Transit Survey (NGTS). After correcting for flares and for the magnetic activity of the host star, and accounting for transit-timing variations, we find the sky-projected spin-orbit angle of planet c to be in the range $\lambda _{\mathrm{c}}=67.8_{-49.0}^{+31.7}$ degrees (1$\sigma$). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b ($\lambda _{\mathrm{b}}=-2.96_{-10.30}^{+10.44}$), and the equatorial plane of the host star, and discuss scenarios that could explain both this and the planet's high density, including secular interactions with other bodies in the system or a giant impact. We note that a significantly misaligned orbit for planet c is in some degree of tension with the dynamical stability of the system, and with the fact that we see both planets in transit, though these arguments alone do not preclude such an orbit. Further observations would be highly desirable to constrain the spin-orbit angle of planet c more precisely.

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: dynamical evolution and stability - planets and satellites: formation - stars: activity - stars: individual: AU Microscopii

Simbad objects: 11

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Number of rows : 11
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 3167 PM* 00 34 57.5242131960 +04 22 53.284093032       8.4   K0V 128 0
2 NAME V1298 Tau b Pl 04 05 19.5909996648 +20 09 25.563233736           ~ 79 0
3 TOI-942b Pl 05 06 35.8911413136 -20 14 44.143841292           ~ 33 0
4 * bet Pic b Pl 05 47 17.0876901 -51 03 59.441135           ~ 627 1
5 WASP-25b Pl 13 01 26.3760406392 -27 31 19.922387484           ~ 50 1
6 HD 120411b Pl 13 50 06.2797027704 -40 50 08.881076364           ~ 60 0
7 NAME beta Pic Moving Group MGr 14 30 -42.0           ~ 894 0
8 HD 197481b Pl 20 45 09.5324974119 -31 20 27.237889841           ~ 158 0
9 HD 197481 BY* 20 45 09.5324974119 -31 20 27.237889841   10.05 8.627 9.078 6.593 M1VeBa1 1344 0
10 HD 197481c Pl 20 45 09.5324974119 -31 20 27.237889841           ~ 82 0
11 HD 222259Ab Pl 23 39 39.4808078664 -69 11 44.707735104           ~ 73 0

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