Optimizing Radial Velocity Follow-up Strategies for Single-Transit Exoplanet Candidates

The exoplanet yield of the TESS mission is expected to surpass that of Kepler, and the relatively bright stars observed by TESS will be significantly more amenable to RV follow-up. Yet TESS is more sensitive to detection biases than its predecessor, as close to 75% of the sky coverage of the TESS primary mission has a continuous time baseline of just 27 days. In these regions of the sky, TESS will observe no more than a single transit for any exoplanet with an orbital period longer than a month. The orbital parameters that can be derived for these “single-transit planet candidates” (STPCs) will be poorly constrained relative to those derived for exoplanets observed to transit multiple times, posing a challenge for follow-up observations. But long-period planets are nevertheless worth confirming and characterizing. Here, I present a framework for maximizing the efficiency of RV observations of STPCs. By leveraging information on exoplanet populations from Kepler, I show that one can develop an informed follow-up strategy even without strong constraints on the orbital period or eccentricity. I also highlight how this information can be used to design dynamic, adaptive observing schemes for queue-based instruments such as NEID.