Clarifications on exoplanets

On page 47 of the article in the May 2009 issue of Physics Today, figure 2b is mistakenly credited to Geoff Marcy rather than the National Solar Observatory. The high-resolution solar spectrum was produced with the Fourier-transform spectrometer at the McMath-Pierce Solar Facility in 1984 and serves as a proxy for a high-resolution spectrum of a Sun-like star. Credit for the image should go to NSO/AURA/NSF.

Also, on page 51, the first complete sentence in the second column should read as follows: “The plot assumes a 2.5-m telescope operating at a wavelength of 800 nm with an advanced coronagraph capable of imaging a planet separated from its glaring star by as little as 160 milliarcseconds.”