Subaru Measures the Spin-Orbit Alignment in a Faint Transiting Extrasolar Planetary System
A Japanese/US collaboration led by a researcher from the University of Tokyo observed the transiting extrasolar planetary system TrES-1 and measured the angle between the stellar spin axis and the planetary orbital axis using the Subaru Telescope High Dispersion Spectrograph (HDS). By measuring the degree of alignment in transiting systems, one can constraint planetary formation models proposed to explain the diverse properties of extrasolar planets. It was the third case and the faintest target so far for which the spin-orbit alignment has been measured.
More info: Subaru telescope web page