Planet Search with the Keck/NIRC2 Vortex Coronagraph in Ms-band for Vega

Abstract

Gaps in circumstellar disks can signal the existence of planetary perturbers, making such systems preferred targets for direct imaging observations of exoplanets. Being one of the brightest and closest stars to the Sun, the photometric standard star Vega hosts a two-belt debris disk structure. Together with the fact that its planetary system is being viewed nearly face-on, Vega has been one of the prime targets for planet imaging efforts. Using the vector vortex coronagraph on Keck/NIRC2 in Ms-band at 4.67 $\mu$m, we report the planet detection limits from 1 au to 22 au for Vega with an on-target time of 1.8 h. We reach a 3 Jupiter mass limit exterior to 12 au, which is nearly an order of magnitude deeper than existing studies. Combining with existing radial velocity studies, we can confidently rule out the existence of companions more than ~8 Jupiter mass from 22 au down to 0.1 au for Vega. Interior and exterior to ~4 au, this combined approach reaches planet detection limits down to ~2-3 Jupiter mass using radial velocity and direct imaging, respectively. By reaching multi-Jupiter mass detection limits, our results are expected to be complemented by the planet imaging of Vega in the upcoming observations using the James Webb Space Telescope to obtain a more holistic understanding of the planetary system configuration around Vega.

6 pages, 3 figures, 1 table, A&A accepted. Contrast curve for 2018 observation available in anc folder. Happy Rabbit Year!

References in corpus (14)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• Fundamental limitations of high contrast imaging set by small sample statistics
• VIP: Vortex Image Processing package for high-contrast direct imaging
• Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search
• A Direct Imaging Survey of Spitzer detected debris disks: Occurrence of giant planets in dusty systems
• The JWST Early Release Science Program for the Direct Imaging & Spectroscopy of Exoplanetary Systems
• Reference-star differential imaging on SPHERE/IRDIS
• Constraining the Orbit and Mass of epsilon Eridani b with Radial Velocities, Hipparcos IAD-Gaia DR2 Astrometry, and Multi-epoch Vortex Coronagraphy Upper Limits
• Deep L' and M-band Imaging for Planets Around Vega and epsilon Eridani
• Thermal Infrared Constraint to a Planetary Companion of Vega with the MMT Adaptive Optics System
• Dust Populations in the Iconic Vega Planetary System Resolved by ALMA
• Efficient detection and characterization of exoplanets within the diffraction limit: nulling with a mode-selective photonic lantern
• A decade of radial-velocity monitoring of Vega and new limits on the presence of planets

Cited by in corpus (2)

• Vortex Fiber Nulling for Exoplanet Observations: Implementation and First Light
• Searching for Planets Orbiting Vega with the James Webb Space Telescope