Abstract

I discuss two recent results from the group at Hertfordshire that have the common theme of getting the most out of your photons via high precision polarimetry. The first (shorter) project, is the measurement of the helical magnetic field structure around the outflow from the massive protostar HH135 /136 via imaging circular polarimetry at 1 arcsec resolution. This result provided a sneak preview of what we will learn from ALMA at even finer resolution and was recently published in Nature. The second project is the attempt to detect extrasolar planets in reflected light with Planetpol, a private instrument built at Herts. This project has pushed the boundaries of polarimetric precision by nearly 2 orders of magntitude, achieving sensitivity to fractional polarisations of 1 part per million. Despite this, we have no positive detectons yet, and I discuss why in the context of the recent positive polarimetric detection claimed for HD189733b.