Exoplanet Detection

Untangling dips and pulses in starlight

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Science  27 Feb 2015:
Vol. 347, Issue 6225, pp. 961
DOI: 10.1126/science.347.6225.961-a

Five small rocky planets orbit the star Kepler-444

ILLUSTRATION: TIAGO CAMPANTE/PETER DEVINE

The menagerie of known exoplanets continues to grow with Kepler data. The NASA spacecraft has monitored stars for brightness dips due to planetary transits, enabling Campante et al. to find five rocky planets orbiting the K star Kepler-444—all between Mercury and Venus in size. Kepler's precise photometry also allowed the team to measure the star's asteroseismic pulsations. A comparison of those values with stellar evolution models revealed an age of 11.2 ± 1.0 billion years, or 80% as old as the universe itself. A planetary system this old (over twice the age of Earth) demonstrates the wide time frame in which Earth-sized planets have existed and helps astronomers discern the earliest times of planet formation.

Astrophys. J. 10.1088/0004-637X/799/2/170 (2015).

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