Transits Probabilities Around Hypervelocity and Runaway Stars

TL;DR

This paper investigates the likelihood of detecting planetary transits and radial velocity signals around hypervelocity and runaway stars, suggesting that while transits are rare, radial velocity surveys have high detection potential with upcoming instruments.

Contribution

It introduces the concept of searching for planets around hypervelocity and runaway stars and evaluates detection probabilities using current and future observational tools.

Findings

Transit probability around these stars is between 10^{-3} and 10^{-1}.

Radial velocity detection chances are high with upcoming spectrographs.

Observations of 10-1000 high-velocity stars are needed to find transiting planets.

Abstract

In the blooming field of exoplanetary science, NASA's Kepler Space Telescope has revolutionized our understanding of exoplanets. Kepler's very precise and long-duration photometry is ideal for detecting planetary transits around Sun-like stars. The forthcoming Transiting Exoplanet Survey Satellite (TESS) is expected to continue Kepler's legacy. Along with transits, the Doppler technique remains an invaluable tool for discovering planets. The next generation of spectrographs, such as G-CLEF, promises precision radial velocity measurements. In this paper, we explore the possibility of detecting planets around hypervelocity and runaway stars, which should host a very compact system as consequence of their turbulent origin. We find that the probability of a multi-planetary transit is $10^{-3}\lesssim P\lesssim 10^{-1}$. We therefore need to observe $\sim 10-1000$ high-velocity stars to spot a transit. However, even if transits are rare around runaway and hypervelocity stars, the chances of detecting such planets using radial velocity surveys is high. We predict that the European Gaia satellite, along with TESS and the new-generation spectrographs G-CLEF and ESPRESSO, will spot planetary systems orbiting high-velocity stars.