The young HD 73583 (TOI-560) planetary system: two 10-M mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf

GANDOLFI, D.; VILLARREAL D'ANGELO, C.; ODDO, D.; SOUSA, S.G.; HOWELL, S.; EISNER, N.; BAYLISS, D.; AIGRAIN, S.; TWICKEN, J.D.; VAN EYLEN, V.; ALARCON, J.; BARRADO, D.; BOUCHY, F.; BURT, J.; CHATURVEDI, P.; CRANE, J.; COLLINS, K.I.; DELINE, A.; FIGUEIRA, P.; GOAD, M.R.; HADJIGEORGHIOU, A.; HARRIS, M.; HOJJATPANAH, S.; KORTH, J.; MARMIER, M.; ARMSTRONG, D.J.; MURGAS, F.; VIDOTTO, A.A.; OSBORN, A.; BARRAGÁN, O.; ISAACSON, H.; CARLEO, I.; RAIMBAULT, M.; FRIDLUND, M.; OKLOP?I?, A.; STOCKDALE, C.; HELLIER, C.; COLLINS, K.; SCHWARZ, R.P.; REDFIELD, S.; PERSSON, C.M.; SEAGER, S.; DRAGOMIR, D.; SKARKA, M.; HOWARD, A.; KLEIN, B.; TAN, T.G.; GEORGIEVA, I.Y.; TESKE, J.; NIELSEN, L.D.; WHEATLEY, P.J.; ESPOSITO, M.; ZHANG, M.; WANG, S.X.; ADIBEKYAN, V.; JENKINS, J.; AKANA MURPHY, J.M.; BENNEKE, B.; RODLER, F.; ANDERSON, D.R.; BUTLER, R.P.; BARROS, S.C.C.; CASEWELL, S.; BRYANT, E.M.; COCHRAN, W.D.; CABRERA, J.; CROUZET, N.; CLOUTIER, R.; DEEG, H.J.; CROSSFIELD, I.; DUMUSQUE, X.; DAI, F.; GNILKA, C.; DEMANGEON, O.D.S.; GUTIÉ

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022 vol. 514 p. 1606 - 1627

0035-8711

We present the discovery and characterization of two transiting planets observed by TESS in the light curves of the young and bright (V = 9.67) star HD73583 (TOI-560). We perform an intensive spectroscopic and photometric space-and ground-based follow-up in order to confirm and characterize the system. We found that HD73583 is a young (∼500 Myr) active star with a rotational period of 12.08 ± 0.11 d, and a mass and radius of 0.73 ± 0.02 M and 0.65 ± 0.02 R, respectively. HD 73583 b (Pb = 6.3980420-0.0000062+ 0.0000067 d) has a mass and radius of 10.2-3.1+ 3.4 M and 2.79 ± 0.10 R, respectively, which gives a density of 2.58-0.81+ 0.95 g, cm-3. HD 73583 c (Pc = 18.87974-0.00074+ 0.00086 d) has a mass and radius of 9.7-1.7+ 1.8 M and 2.39-0.09+ 0.10 R, respectively, which translates to a density of 3.88-0.80+ 0.91g, cm-3. Both planets are consistent with worlds made of a solid core surrounded by a volatile envelope. Because of their youth and host star brightness, they both are excellent candidates to perform transmission spectroscopy studies. We expect ongoing atmospheric mass-loss for both planets caused by stellar irradiation. We estimate that the detection of evaporating signatures on H and He would be challenging, but doable with present and future instruments.