A Super-Earth Transiting a Naked-Eye Star

Abstract

We have detected transits of the innermost planet "e" orbiting 55 Cnc (V=6.0), based on two weeks of nearly continuous photometric monitoring with the MOST space telescope. The transits occur with the period (0.74 d) and phase that had been predicted by Dawson & Fabrycky, and with the expected duration and depth for the crossing of a Sun-like star by a hot super-Earth. Assuming the star's mass and radius to be 0.963_{-0.029}^{+0.051} M_sun and 0.943 +/- 0.010 R_sun, the planet's mass, radius, and mean density are 8.63 +/- 0.35 Mearth, 2.00 +/- 0.14 Rearth, and 5.9_{-1.1}^{+1.5} g/cm^3. The mean density is comparable to that of Earth, despite the greater mass and consequently greater compression of the interior of 55 Cnc e. This suggests a rock-iron composition supplemented by a significant mass of water, gas, or other light elements. Outside of transits, we detected a sinusoidal signal resembling the expected signal due to the changing illuminated phase of the planet, but with a full range (168 +/- 70 ppm) too large to be reflected light or thermal emission. This signal has no straightforward interpretation and should be checked with further observations. The host star of 55 Cnc e is brighter than that of any other known transiting planet, which will facilitate future investigations.

ApJ Letters, in press (v3) Minor changes/clarifications; (v2) Revised after fixing an error in the data reduction pipeline; for details see http://web.mit.edu/~jwinn/www/55cnc_response.txt

References in corpus (14)

• Mass-Radius Relationships for Solid Exoplanets
• A Closely-Packed System of Low-Mass, Low-Density Planets Transiting Kepler-11
• The effect of red noise on planetary transit detection
• KEPLER's First Rocky Planet: Kepler-10b
• Structure and Evolution of Nearby Stars with Planets II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog
• Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
• Five Planets Orbiting 55 Cancri
• The Transit Light Curve (TLC) Project. I. Four Consecutive Transits of the Exoplanet XO-1b
• The Transit Light Curve Project. III. Tres Transits of TrES-1
• MOST detects variability on tau Bootis possibly induced by its planetary companion
• Could the 55 Cancri Planetary System Really Be in the 3:1 Mean Motion Resonance?
• Asteroseismology of the Transiting Exoplanet Host HD 17156 with HST FGS
• Precise Estimates of the Physical Parameters for the Exoplanet System HD-17156 Enabled by HST FGS Transit and Asteroseismic Observations
• A Search for wide visual companions of exoplanet host stars - The Calar Alto Survey

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