Transits of Known Planets Orbiting a Naked-Eye Star

Abstract

Some of the most scientifically valuable transiting planets are those that were already known from radial velocity (RV) surveys. This is primarily because their orbits are well characterized and they preferentially orbit bright stars that are the targets of RV surveys. The Transiting Exoplanet Survey Satellite ({\it TESS}) provides an opportunity to survey most of the known exoplanet systems in a systematic fashion to detect possible transits of their planets. HD~136352 (Nu${}^2$~Lupi) is a naked-eye ($V=5.78$) G-type main-sequence star that was discovered to host three planets with orbital periods of 11.6, 27.6, and 108.1 days via RV monitoring with the HARPS spectrograph. We present the detection and characterization of transits for the two inner planets of the HD~136352 system, revealing radii of $1.482_{-0.056}^{+0.058}$~$R_{\oplus }$ and $2.608_{-0.077}^{+0.078}$~$R_{\oplus }$ for planets b and c, respectively. We combine new HARPS observations with RV data from Keck/HIRES and the AAT, along with {\it TESS} photometry from Sector 12, to perform a complete analysis of the system parameters. The combined data analysis results in extracted bulk density values of ${\rho }_b=7.8_{-1.1}^{+1.2}$~gcm${}^{-3}$ and ${\rho }_c=3.50_{-0.36}^{+0.41}$~gcm${}^{-3}$ for planets b and c, respectively, thus placing them on either side of the radius valley. The combination of the multi-transiting planet system, the bright host star, and the diversity of planetary interiors and atmospheres means this will likely become a cornerstone system for atmospheric and orbital characterization of small worlds.

13 pages, 4 figures, 3 tables, accepted for publication in the Astronomical Journal

References in corpus (16)

• The Transiting Exoplanet Survey Satellite
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• EXOFAST: A fast exoplanetary fitting suite in IDL
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• Growth Model Interpretation of Planet Size Distribution
• Stellar Abundances in the Solar Neighborhood: The Hypatia Catalog
• The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres
• A Catalog of Kepler Habitable Zone Exoplanet Candidates
• Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search
• On the Frequency of Potential Venus Analogs from Kepler Data
• Constraining Orbital Parameters Through Planetary Transit Monitoring
• Two massive rocky planets transiting a K-dwarf 6.5 parsecs away
• Detection of a transit by the planetary companion of HD 80606
• Architectures of Planetary Systems and Implications for their Formation
• The TESS-Keck Survey I: A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras
• Observational Window Functions in Planet Transit Surveys

Cited by in corpus (22)

• The TESS Objects of Interest Catalog from the TESS Prime Mission
• Transit detection of the long-period volatile-rich super-Earth ${\nu }^2$ Lupi d with $CHEOPS$
• Uncovering the true periods of the young sub-Neptunes orbiting TOI-2076
• New Perspectives on the Exoplanet Radius Gap from a Mathematica Tool and Visualized Water Equation of State
• Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions
• Science Extraction from TESS Observations of Known Exoplanet Hosts
• The HD 93963 A transiting system: A 1.04d super-Earth and a 3.65 d sub-Neptune discovered by TESS and CHEOPS
• A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113
• Spatially resolved spectroscopy across stellar surfaces. V. Observational prospects: Toward Earth-like exoplanet detection
• A full transit of ${\nu }^2$ Lupi d and the search for an exomoon in its Hill sphere with CHEOPS
• The Atmospheres of Rocky Exoplanets II. Influence of surface composition on the diversity of cloud condensates
• The GAPS Programme at TNG XL: A puffy and warm Neptune-sized planet and an outer Neptune-mass candidate orbiting the solar-type star TOI-1422
• Exoplanet atmosphere evolution: emulation with neural networks
• Luminaries in the Sky: The TESS Legacy Sample of Bright Stars. I. Asteroseismic detections in naked-eye main-sequence and sub-giant solar-like oscillators
• RV-exoplanet eccentricities: Good, Beta, and Best
• Revised Properties and Dynamical History for the HD 17156 System
• Variability of Known Exoplanet Host Stars Observed by TESS
• Planetary system architectures with low-mass inner planets: Direct imaging exploration of mature systems beyond 1 au
• Null transit detections of 68 radial velocity exoplanets observed by TESS
• The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution
• SPORES-HWO. II. Companion Mass Limits and Updated Planet Properties for 120 Future Exoplanet Imaging Targets from 35 yr of Precise Doppler Monitoring
• The Visual Survey Group: A Decade of Hunting Exoplanets and Unusual Stellar Events with Space-Based Telescopes