The EPRV Research Coordination Network (RCN), sponsored by NASA’s Exoplanet Exploration Program, aims to support increased communication and collaboration within the radial velocity community as we work towards the goal of obtaining robust mass measurements for Earth analog planets.

Membership is open to the community and we invite participants from all corners of the RV community and related fields, including but not limited to: observational efforts, instrumentation, data analysis techniques, solar studies, and stellar variability mitigation. Please see the side bar for instructions / links on how to join the RCN.

Our next EPRV colloquium will take place on May 23rd and feature Jean-Baptiste Delissle from the University of Geneva. Recordings of previous colloquia are available via the RCN Google Drive.

Abstract: The ESA Gaia mission has been mapping the sky since 2014 and will run out of propellant in January 2025. The next data release (DR4) will be the first to include astrometric timeseries, corresponding to data taken during the 5 years nominal mission (2014-2019). These astrometric timeseries are complementary with ground-based RVs in two ways. First, for outer giant planets, astrometry and (moderately precise) RVs can be combined to improve the detection efficiency and better constrain all orbital parameters. Second, EPRVs (and transits) allow to probe the presence of smaller planets in the inner parts of the systems. Combining the constraints on outer giant planets from Gaia and on smaller inner planets from EPRVs is key to better understand the global architecture of planetary systems.

This presentation will be in two parts.
In the first part, I will focus on Gaia astrometry and its combination with RVs, for the detection and characterization of giant planets and brown dwarfs.
In the second part, I will switch to EPRV timeseries analysis, and more specifically to current developments on the modeling of stellar activity with physically motivated Gaussian processes.

Background on the RCN

The 2018 National Academies’ Exoplanet Science Strategy, which provided input to the Astro 2020 Decadal Survey, acknowledged the importance of the radial velocity method “to provide essential mass, orbit, and census information to support both transiting and directly imaged exoplanet science for the foreseeable future” and recommended that “NASA and NSF should establish a strategic initiative in extremely precise radial velocities (EPRV) to develop methods and facilities for measuring the masses of temperate terrestrial planets orbiting Sun-like stars.” Subsequently, a community Extreme Precision Radial Velocity (EPRV) Working Group was chartered, which developed a roadmap for advancing the radial velocity technique to the point where EPRV detection or exclusion of Earth analogs orbiting nearby target stars of a future direct imaging mission would be feasible.

With the Astro2020 Decadal Survey recommendation for NASA to develop a large infrared/optical/ultraviolet space telescope capable of observing and spectrally characterizing potentially habitable exoplanets orbiting nearby stars, development of EPRV capabilities is critical as they will provide the only method potentially capable of discovering Earth analogs from the ground and measuring their masses. As part of its plan to “break the stellar variability barrier” and work towards enabling EPRV surveys capable of measuring the masses of Earth analogs, the EPRV WG report recommended that NASA establish an EPRV Research Coordination Network (RCN) of scientists across disciplines (solar, stellar, exoplanetary) and instruments.“ Thus, the development of this RCN, which endeavors to support the EPRV community in advancing towards the goal of detecting temperate, terrestrial, planets around Sun-like stars.