A SUPER-EARTH TRANSITING A NAKED-EYE STAR

2011/04/30 by Joshua N. Winn, Jaymie M. Matthews, Rebekah I. Dawson +11 · 14 citations
Physics and Astronomy · Social Sciences · #Astronomy and Astrophysical Research #Educational Leadership and Practices #Hot Jupiter #Planet #Planetary system #RADIUS #SIGNAL (programming language) #Star (game theory) #Stellar, planetary, and galactic studies #Thermal #astro-ph.EP

paper · pdf · doi:10.1088/2041-8205/737/1/l18

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

arxiv created 2011/07/07 · openalex publication_date 2011/07/22 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

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 days) 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 +0.051 − 0.029 M ☉ and 0.943 ± 0.010 R ☉ , the planet's mass, radius, and mean density are 8.63 ± 0.35 M ⊕ , 2.00 ± 0.14 R ⊕ , and 5.9 +1.5 − 1.1 g cm −3 , respectively. 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.

Citations

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• A super-Earth transiting a nearby low-mass star
• A map of the day–night contrast of the extrasolar planet HD 189733b
• The effect of red noise on planetary transit detection

Cited by

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• Temperate Super-Earths/Mini-Neptunes around M/K Dwarfs Consist of Two Populations Distinguished by Kepler and Spitzer Transit Depth Variations
• Radial velocity data analysis with compressed sensing techniques
• Hubble Space Telescope search for the transit of the Earth-mass exoplanet α Centauri B b
• Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating
• A LOW STELLAR OBLIQUITY FOR WASP-47, A COMPACT MULTIPLANET SYSTEM WITH A HOT JUPITER AND AN ULTRA-SHORT PERIOD PLANET
• A map of the large day–night temperature gradient of a super-Earth exoplanet
• A SEARCH FOR TRANSITS OF GJ 581e AND CHARACTERIZATION OF THE HOST STAR VARIABILITY USINGMOSTSPACE TELESCOPE PHOTOMETRY
• Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities
• K2-HERMES II. Planet-candidate properties from K2 Campaigns 1-13
• The Super Earth–Cold Jupiter Relations
• DENSITY AND ECCENTRICITY OFKEPLERPLANETS
• Molecular detectability in exoplanetary emission spectra

Related

• Detection of a transit of the super-Earth 55 Cancri e with warm Spitzer
• From Earths to Super-Earths: Five New Small Planets Transiting M Dwarf Stars
• A super-Earth transiting a nearby low-mass star
• A Non-Detection of Iron in the First High-Resolution Emission Study of the Lava Planet 55 Cnc e
• 55 CANCRI: STELLAR ASTROPHYSICAL PARAMETERS, A PLANET IN THE HABITABLE ZONE, AND IMPLICATIONS FOR THE RADIUS OF A TRANSITING SUPER-EARTH