The young HD 73583 (TOI-560) planetary system: Two 10-M${}_{\oplus }$ mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf

Abstract

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 $0.73\pm 0.02M_{\odot }$ and $0.65\pm 0.02R_{\odot }$, 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$2.79\pm 0.10R_{\oplus }$, respectively, that gives a density of $2.58_{-0.81}^{0.95}\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$. 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 $3.88_{-0.80}^{+0.91}\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$. 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.

Accepted for publication in MNRAS

References in corpus (51)

• The Transiting Exoplanet Survey Satellite
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Growth Model Interpretation of Planet Size Distribution
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• Basic physical parameters of a selected sample of evolved stars
• The TESS Objects of Interest Catalog from the TESS Prime Mission
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• A new list of thorium and argon spectral lines in the visible
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• SOAP 2.0: A tool to estimate the photometric and radial velocity variations induced by stellar spots and plages
• The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres
• TW Hydrae: evidence of stellar spots instead of a Hot Jupiter
• A planet within the debris disk around the pre-main-sequence star AU Microscopii
• ARES v2 - new features and improved performance
• Long Term Evolution of Close Planets Including the Effects of Secular Interactions
• Zodiacal Exoplanets in Time (ZEIT) IV: seven transiting planets in the Praesepe cluster
• Abundance to age ratios in the HARPS-GTO sample with Gaia DR2: Chemical clocks for a range of [Fe/H]
• A method for the direct determination of the surface gravities of transiting extrasolar planets
• New constraints on the planetary system around the young active star AU Mic. Two transiting warm Neptunes near mean-motion resonance
• SWEET-Cat 2.0: The Cat just got SWEETer; Higher quality spectra and precise parallaxes from GAIA eDR3
• TESS Hunt for Young and Maturing Exoplanets (THYME) II: A 17 Myr Old Transiting Hot Jupiter in the Sco-Cen Association
• pyaneti II: A multidimensional Gaussian process approach to analysing spectroscopic time-series
• Investigating the young AU~Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass
• Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions at 1-1000 AU and Implications for Small Planet Detection
• Diving Beneath the Sea of Stellar Activity: Chromatic Radial Velocities of the Young AU Mic Planetary System
• Speckle Imaging Excludes Low-Mass Companions Orbiting the Exoplanet Host Star TRAPPIST-1
• Escaping Helium from TOI 560.01, a Young Mini Neptune
• TESS Hunt for Young and Maturing Exoplanets (THYME) IV: Three small planets orbiting a 120 Myr-old star in the Pisces--Eridanus stream
• Two young planetary systems around field stars with ages between 20-320 Myr from TESS
• Three Small Super-Earths Transiting the nearby star GJ 9827
• A Model of the H$\alpha$ and Na Transmission Spectrum of HD 189733b
• Simultaneous TESS and NGTS Transit Observations of WASP-166b
• Lyα Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions
• Effects of the stellar wind on the Ly-alpha transit of close-in planets
• Detection of the hydrogen Balmer lines in the ultra-hot Jupiter WASP-33b
• The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap
• The Changing Face of $\alpha$ Centauri B: Probing plage and stellar activity in K-dwarfs
• A transiting warm giant planet around the young active star TOI-201
• Mass determinations of the three mini-Neptunes transiting TOI-125
• The dichotomy of atmospheric escape in AU Mic b
• TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
• The Magellan-TESS Survey I: Survey Description and Mid-Survey Results
• Decoding the radial velocity variations of HD41248 with ESPRESSO
• Caught in the Act: Core-powered Mass-loss Predictions for Observing Atmospheric Escape
• Masses for the seven planets in K2-32 and K2-233. Four diverse planets in resonant chain and the first young rocky worlds
• GJ 436b and the stellar wind interaction: simulations constraints using Ly$\alpha$ and H$\alpha$ transits
• Hydrodynamical interaction of stellar and planetary winds: effects of charge exchange and radiation pressure on the observed Ly$\alpha$ absorption
• Influence of the Sun-like magnetic cycle on exoplanetary atmospheric escape
• Hot planets around cool stars -- two short-period mini-Neptunes transiting the late K-dwarf TOI-1260
• An eclipsing M-dwarf close to the hydrogen burning limit from NGTS

Cited by in corpus (31)

• Detection of Atmospheric Escape from Four Young Mini Neptunes
• A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067
• The GAPS Programme with HARPS-N at TNG. XXXVII. A precise density measurement of the young ultra-short period planet TOI-1807 b
• The MOPYS project: A survey of 70 planets in search of extended He I and H atmospheres. No evidence of enhanced evaporation in young planets
• Connection between planetary He I $\lambda$10830 Å absorption and extreme-ultraviolet emission of planet-host stars
• Revisiting K2-233 spectroscopic time-series with multidimensional Gaussian Processes
• On the origin of the non-detection of metastable HeI in the upper atmosphere of the hot Jupiter WASP-80b
• TOI-2196 b: Rare planet in the hot Neptune desert transiting a G-type star
• Generalized Peas-in-a-Pod: Extending Intra-System Mass Uniformity to Non-TTV Systems via the Gini Index
• Resonant sub-Neptunes are puffier
• Optical and near-infrared stellar activity characterization of the early M dwarf Gl~205 with SOPHIE and SPIRou
• Characterization of a set of small planets with TESS and CHEOPS and an analysis of photometric performance
• The young mini-Neptune HD 207496b that is either a naked core or on the verge of becoming one
• TOI-179: a young system with a transiting compact Neptune-mass planet and a low-mass companion in outer orbit
• TOI-1801 b: A temperate mini-Neptune around a young M0.5 dwarf
• Exoplanet atmosphere evolution: emulation with neural networks
• Non-detection of Helium in the Hot Jupiter WASP-48b
• Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass
• TOI-837b is a Young Saturn-sized Exoplanet with a Massive 70 $M_{\oplus }$ Core
• TESS and CHEOPS Discover Two Warm Sub-Neptunes Transiting the Bright K-dwarf HD 15906
• Dynamical masses of two young transiting sub-Neptunes orbiting HD 63433
• Planet Hunters TESS V: a planetary system around a binary star, including a mini-Neptune in the habitable zone
• TOI-733 b: a planet in the small-planet radius valley orbiting a Sun-like star
• The GAPS Programme at TNG. LXV. Precise density measurement of TOI-1430 b, a young planet with an evaporating atmosphere
• Using Doppler Imaging to model stellar activity and search for planets around Sun-like stars
• A sub-Neptune transiting the young field star HD 18599 at 40 pc
• Three young planets around the K-dwarf K2-198: High-energy environment, evaporation history and expected future
• Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-Hydrodynamic Code
• The GAPS Programme at TNG. LIX. A characterisation study of the $\sim$300 Myr old multi-planetary system orbiting the star BD+40 2790 (TOI-2076)
• Homogeneous search for spot transits in Kepler and TESS photometry of K $-$ M-type main-sequence stars
• The GAPS Programme at the TNG: LXX. TOI-5734b: A hot sub-Neptune orbiting a relatively young K dwarf with an Earth-like density