Abstract
Our understanding of extra-solar planet systems is highly driven by advances in observations in the past decade. Thanks to high precision spectrographs, we are able to reveal unseen companions to stars with the radial velocity method. High precision photometry from the space, especially with the Kepler mission, enables us to detect planets when they transit their stars and dim the stellar light by merely one percent or smaller. Ultra wide-field, high cadence, continuous monitoring of the Galactic bulge from different sites around the southern hemisphere provides us the opportunity to observe microlensing effects caused by planetary systems from the solar neighborhood, all the way to the Milky Way center. The exquisite AO imaging from ground-based large telescopes, coupled with high-contrast coronagraph, captured the photons directly emitted by planets around other stars. In this article, I present a concise review of the extra-solar planet discoveries, discussing the strengths and weaknesses of the major planetary detection methods, providing an overview of our current understanding of planetary formation and evolution given the tremendous observations delivered by various methods, as well as on-going and planned observation endeavors to provide a clear picture of extra-solar planetary systems.
Highlights
Our understanding of extra-solar planet systems is highly driven by advances in observations in the past decade
The very first extra-solar planets were not found around a main-sequence star, but rather an neutron star using the change in pulsar timing [1]
While the result received a vast amount of critics, especially with the speculations that such kind of radial velocity signal could be mimicked by stellar spots, it has turned out that the radial velocity signal is truly coming from a planetary mass companion
Summary
Searching for and characterization of planets beyond the solar system has been a long quest for observational astronomy. The benefit of microlensing is that it only relies on the gravitational signal of the planet, but does not utilize the lights from the host star nor from the exoplanet itself, we can detect very low mass (e.g., earth-like) exoplanet out to a very large orbits (beyond the snow-line), which is otherwise not possible with radial velocity, transit, or direct imaging methods. In 2008, astronomers were able to detect photons directly emitted from the exoplanets for the first time This is only possible with the exquisite spatial resolution enabled by ground-based AO instruments, coupled with high contrast imaging capability, delivered by the Keck and Gemini telescopes at that time. Detections of multiple exoplanet systems—with a very close-in exoplanet and a wide-separation exoplanet orbiting the same host star—would provide smoking gun evidence to support such scenario
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
