... New technique measures mass of exoplanets . ... Now, scientists at the Massachusetts Institute of Technology (MIT) have developed a new technique for determining the mass of exoplanets using only their transmission spectra dips in light as a planet passes in front of its star. ... To determine the mass of an exoplanet using transmission spectroscopy, de Wit relied on the effect that a planet s mass has on its atmosphere, as transmission spectra give information on a planet s atmospheric properties. ...