Optimizing Doppler Surveys for Planet Yield

One of the most promising methods of discovering nearby, low-mass planets in the habitable zones of stars is the precision radial velocity technique. However, there are many challenges that must be overcome to efficiently detect low-amplitude Doppler signals. This is both due to the required instrumental sensitivity and the limited amount of observing time. In this article, we examine statistical and instrumental effects on precision radial velocity detection of extrasolar planets, an approach by which we maximize the planet yield in a fixed amount of observing time available on a given telescope. From this perspective, we show that G and K dwarfs observed at 400–600 nm are the best targets for surveys complete down to a given planet mass and out to a specified orbital period. Overall we find that M dwarfs observed at 700–800 nm are the best targets for habitable-zone planets, particularly when including the effects of systematic noise floors. Also, we give quantitative specifications of the instrumental stability necessary to achieve the required velocity precision.