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

Publication date: 
Main author: 
Barragán, O.
IAA authors: 
Luque, R.
Barragán, O.;Armstrong, D. J.;Gandolfi, D.;Carleo, I.;Vidotto, A. A.;Villarreal D'Angelo, C.;Oklopčić, A.;Isaacson, H.;Oddo, D.;Collins, K.;Fridlund, M.;Sousa, S. G.;Persson, C. M.;Hellier, C.;Howell, S.;Howard, A.;Redfield, S.;Eisner, N.;Georgieva, I. Y.;Dragomir, D.;Bayliss, D.;Nielsen, L. D.;Klein, B.;Aigrain, S.;Zhang, M.;Teske, J.;Twicken, J. D.;Jenkins, J.;Esposito, M.;Van Eylen, V.;Rodler, F.;Adibekyan, V.;Alarcon, J.;Anderson, D. R.;Akana Murphy, J. M.;Barrado, D.;Barros, S. C. C.;Benneke, B.;Bouchy, F.;Bryant, E. M.;Butler, R. P.;Burt, J.;Cabrera, J.;Casewell, S.;Chaturvedi, P.;Cloutier, R.;Cochran, W. D.;Crane, J.;Crossfield, I.;Crouzet, N.;Collins, K. I.;Dai, F.;Deeg, H. J.;Deline, A.;Demangeon, O. D. S.;Dumusque, X.;Figueira, P.;Furlan, E.;Gnilka, C.;Goad, M. R.;Goffo, E.;Gutiérrez-Canales, F.;Hadjigeorghiou, A.;Hartman, Z.;Hatzes, A. P.;Harris, M.;Henderson, B.;Hirano, T.;Hojjatpanah, S.;Hoyer, S.;Kabáth, P.;Korth, J.;Lillo-Box, J.;Luque, R.;Marmier, M.;Močnik, T.;Muresan, A.;Murgas, F.;Nagel, E.;Osborne, H. L. M.;Osborn, A.;Osborn, H. P.;Palle, E.;Raimbault, M.;Ricker, G. R.;Rubenzahl, R. A.;Stockdale, C.;Santos, N. C.;Scott, N.;Schwarz, R. P.;Shectman, S.;Raimbault, M.;Seager, S.;Ségransan, D.;Serrano, L. M.;Skarka, M.;Smith, A. M. S.;Šubjak, J.;Tan, T. G.;Udry, S.;Watson, C.;Wheatley, P. J.;West, R.;Winn, J. N.;Wang, S. X.;Wolfgang, A.;Ziegler, C.
Monthly Notices of the Royal Astronomical Society
Publication type: 
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<SUB>⊙</SUB> and 0.65 ± 0.02 R<SUB>⊙</SUB>, respectively. HD 73583 b (P<SUB>b</SUB> = $6.3980420 _{ - 0.0000062 } ^ { + 0.0000067 }$ d) has a mass and radius of $10.2 _{ - 3.1 } ^ { + 3.4 }$ M<SUB>⊕</SUB> and 2.79 ± 0.10 R<SUB>⊕</SUB>, respectively, which gives a density of $2.58 _{ - 0.81 } ^ { + 0.95 }$ ${\rm g\, cm^{-3}}$. HD 73583 c (P<SUB>c</SUB> = $18.87974 _{ - 0.00074 } ^ { + 0.00086 }$ d) has a mass and radius of $9.7 _{ - 1.7 } ^ { + 1.8 }$ M<SUB>⊕</SUB> and $2.39 _{ - 0.09 } ^ { + 0.10 }$ R<SUB>⊕</SUB>, respectively, which 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.
ADS Bibcode: 
techniques: photometric;techniques: radial velocities;planets and satellites: individual: HD 73583 (TOI-560);stars: activity;Astrophysics - Earth and Planetary Astrophysics;Astrophysics - Solar and Stellar Astrophysics