The young HD 73583 (TOI-560) planetary system: Two 10-M$_\oplus$ mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf
Creators: name: Barragán, O.
name: Armstrong, D. J.
name: Gandolfi, D.
name: Carleo, I.
name: Vidotto, A. A.
name: D'Angelo, C. Villarreal
name: Oklopčić, A.
name: Isaacson, H.
name: Oddo, D.
name: Collins, K.
name: Fridlund, M.
name: Sousa, S. G.
name: Persson, C. M.
name: Hellier, C.
name: Howell, S.
name: Howard, A.
name: Redfield, S.
name: Eisner, N.
name: Georgieva, I. Y.
name: Dragomir, D.
name: Bayliss, D.
name: Nielsen, L. D.
name: Klein, B.
name: Aigrain, S.
name: Zhang, M.
name: Teske, J.
name: Twicken, J D.
name: Jenkins, J.
name: Esposito, M.
name: Van Eylen, V.
name: Rodler, F.
name: Adibekyan, V.
name: Alarcon, J.
name: Anderson, D. R.
name: Murphy, J. M. Akana
name: Barrado, D.
name: Barros, S. C. C.
name: Benneke, B.
name: Bouchy, F.
name: Bryant, E. M.
name: Butler, P.
name: Burt, J.
name: Cabrera, J.
name: Casewell, S.
name: Chaturvedi, P.
name: Cloutier, R.
name: Cochran, W. D.
name: Crane, J.
name: Crossfield, I.
name: Crouzet, N.
name: Collins, K. I.
name: Dai, F.
name: Deeg, H. J.
name: Deline, A.
name: Demangeon, O. D. S.
name: Dumusque, X.
name: Figueira, P.
name: Furlan, E.
name: Gnilka, C.
name: Goad, M. R.
name: Goffo, E.
name: Gutiérrez-Canales, F.
name: Hadjigeorghiou, A.
name: Hartman, Z.
name: Hatzes, A. P.
name: Harris, M.
name: Henderson, B.
name: Hirano, T.
name: Hojjatpanah, S.
name: Hoyer, S.
name: Kabáth, P.
name: Korth, J.
name: Lillo-Box, J.
name: Luque, R.
name: Marmier, M.
name: Močnik, T.
name: Muresan, A.
name: Murgas, F.
name: Nagel, E.
name: Osborne, H. L. M.
name: Osborn, A.
name: Osborn, H. P.
name: Palle, E.
name: Raimbault, M.
name: Ricker, G. R.
name: Rubenzahl, R A.
name: Stockdale, C.
name: Santos, N. C.
name: Scott, N.
name: Schwarz, R. P.
name: Shectman, S.
name: Raimbault, M.
name: Seager, S.
name: Ségransan, D.
name: Serrano, L. M.
name: Skarka, M.
name: Smith, A. M. S.
name: Šubjak, J.
name: Tan, T. G.
name: Udry, S.
name: Watson, C.
name: Wheatley, P. J.
name: West, R.
name: Winn, J. N.
name: Wang, S. X.
name: Wolfgang, A.
name: Ziegler, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the discovery and characterisation of two transiting planets observed by \textit{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 characterise the system. We found that HD73583 is a young ($\sim 500$~Myr) active star with a rotational period of $12.08 \pm 0.11 $\,d, and a mass and radius of $ 0.73 \pm 0.02 M_\odot$ and $0.65 \pm 0.02 R_\odot$, respectively. HD73583 b ($P_b=6.3980420 _{ - 0.0000062 }^{+0.0000067}$ d) has a mass and radius of $10.2 _{-3.1}^{+3.4} M_\oplus$ and$2.79 \pm 0.10 R_\oplus$, respectively, that gives a density of $2.58 _{-0.81}^{ 0.95} {\rm g\,cm^{-3}}$. HD73583 c ($P_c= 18.87974 _{-0.00074 }^{+0.00086}$) has a mass and radius of $9.7_{-1.7} ^ {+1.8} M_\oplus$ and $2.39_{-0.09}^{+0.10} R_\oplus$, respectively, this translates to a density of $3.88 _{-0.80}^{+0.91} {\rm g\,cm^{-3}}$. 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.
description: Accepted for publication in MNRAS