Earth analogues, and to a lesser extent super-Earths, have been so elusive in part because the two primary modes of exoplanet detection favor larger, hotter planets. (scientificamerican.com)
While Hubble is not responsible for most exoplanet detections, it is... (hubble25th.org)
Graduate student Roberto Sanchis - Ojeda, who has studied the effect of starspots on exoplanet detection, says the troublesome patches can make a star's Doppler shift appear larger, dramatically complicating scientists» calculations of a planet's mass. (sciencedaily.com)