FAST RISE OF “NEPTUNE-SIZE” PLANETS (4–8 R⊕) FROM P ∼ 10 TO ∼250 DAYS—STATISTICS OF KEPLER PLANET CANDIDATES UP TO ∼0.75 AU

We infer period (P) and size (R_p) distribution of Kepler transiting planet candidates with R_p> 1 R_Earth and P 10 days, the planet frequency dN_p/d logP for "Neptune-size" planets (R_p = 4-8 R_Earth) increases with period as \propto P^{0.7\pm0.1}. In contrast, dN_p/dlogP for Super-Earth-Size (2-4 R_Earth) as well as Earth-size (1-2 R_Earth) planets are consistent with a nearly flat distribution as a function of period (\propto P^{0.11\pm0.05}) and \propto P^{-0.10\pm0.12}, respectively), and the normalizations are remarkably similar (within a factor of ~ 1.5). The shape of the distribution function is found to be not sensitive to changes in selection criteria of the sample. The implied nearly flat or rising planet frequency at long period appears to be in tension with the sharp decline at ~100 days in planet frequency for low mass planets (planet mass m_p < 30 M_Earth) recently suggested by the HARPS survey.

[1]  B. Scott Gaudi,et al.  Planetary Transits toward the Galactic Bulge , 2000, astro-ph/0004324.

[2]  F. Fressin,et al.  CHARACTERISTICS OF PLANETARY CANDIDATES OBSERVED BY KEPLER. II. ANALYSIS OF THE FIRST FOUR MONTHS OF DATA , 2011, 1102.0541.

[3]  Jong-Hak Woo,et al.  Y2 Isochrones with an Improved Core Overshoot Treatment , 2004 .

[4]  M. R. Haas,et al.  PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER , 2011, 1103.2541.

[5]  S. Udry,et al.  Tertiary Companions to Close Spectroscopic Binaries , 2006, astro-ph/0601518.

[6]  F. Bouchy,et al.  The HARPS search for southern extra-solar planets - XIII. A planetary system with 3 super-Earths (4.2, 6.9, and 9.2 M) , 2008, 0806.4587.

[7]  Sara Seager,et al.  LACK OF INFLATED RADII FOR KEPLER GIANT PLANET CANDIDATES RECEIVING MODEST STELLAR IRRADIATION , 2011, 1110.6180.

[8]  Howard Isaacson,et al.  The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters , 2010, Science.

[9]  C. Moutou,et al.  SOPHIE velocimetry of Kepler transit candidates VII. A false-positive rate of 35% for Kepler close-in giant candidates , 2012, 1206.0601.

[10]  F. Fressin,et al.  THE FALSE POSITIVE RATE OF KEPLER AND THE OCCURRENCE OF PLANETS , 2013, 1301.0842.

[11]  Jonathan J. Fortney,et al.  HOW THERMAL EVOLUTION AND MASS-LOSS SCULPT POPULATIONS OF SUPER-EARTHS AND SUB-NEPTUNES: APPLICATION TO THE KEPLER-11 SYSTEM AND BEYOND , 2012, 1205.0010.

[12]  Kepler planet candidates consistent with core accretion , 2011, 1102.1009.

[13]  A. Youdin.  THE EXOPLANET CENSUS: A GENERAL METHOD APPLIED TO KEPLER , 2011, 1105.1782.

[14]  Howard Isaacson,et al.  MODELING KEPLER TRANSIT LIGHT CURVES AS FALSE POSITIVES: REJECTION OF BLEND SCENARIOS FOR KEPLER-9, AND VALIDATION OF KEPLER-9 d, A SUPER-EARTH-SIZE PLANET IN A MULTIPLE SYSTEM , 2010, 1008.4393.

[15]  Peter Tenenbaum,et al.  DETECTION OF POTENTIAL TRANSIT SIGNALS IN THE FIRST THREE QUARTERS OF Kepler MISSION DATA , 2012, 1201.1048.

[16]  K. Kinemuchi,et al.  ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS , 2012, 1201.5424.

[17]  Michael Shao,et al.  The Occurrence Rate of Earth Analog Planets Orbiting Sunlike Stars , 2011 .

[18]  Las Cumbres Observatory Global Telescope Network,et al.  PLANETARY CANDIDATES OBSERVED BY KEPLER. III. ANALYSIS OF THE FIRST 16 MONTHS OF DATA , 2012, 1202.5852.

[19]  John Asher Johnson,et al.  ON THE LOW FALSE POSITIVE PROBABILITIES OF KEPLER PLANET CANDIDATES , 2011, 1101.5630.

[20]  Martin C. Stumpe,et al.  The Derivation, Properties, and Value of Kepler’s Combined Differential Photometric Precision , 2012, 1208.0595.

[21]  T. Morton.  AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES , 2012, 1206.1568.

[22]  Maximum-likelihood method for estimating the mass and period distributions of extrasolar planets , 2001, astro-ph/0107482.

[23]  Wesley A. Traub,et al.  TERRESTRIAL, HABITABLE-ZONE EXOPLANET FREQUENCY FROM KEPLER , 2011, 1109.4682.

[24]  J. B. Laird,et al.  An abundance of small exoplanets around stars with a wide range of metallicities , 2012, Nature.

[25]  C. Lintott,et al.  PLANET HUNTERS: ASSESSING THE KEPLER INVENTORY OF SHORT-PERIOD PLANETS , 2012, 1205.6769.

[26]  D. Lin,et al.  Toward a Deterministic Model of Planetary Formation. I. A Desert in the Mass and Semimajor Axis Distributions of Extrasolar Planets , 2004 .

[27]  S. Tremaine,et al.  THE STATISTICS OF MULTI-PLANET SYSTEMS , 2011, 1106.5403.

[28]  TERRESTRIAL PLANET FORMATION. I. THE TRANSITION FROM OLIGARCHIC GROWTH TO CHAOTIC GROWTH , 2005, astro-ph/0503568.

[29]  Y. Alibert,et al.  Characterization of exoplanets from their formation - II. The planetary mass-radius relationship , 2012, 1206.3303.

[30]  A. Ofir,et al.  An independent planet search in the Kepler dataset - I. One hundred new candidates and revised Kepler objects of interest , 2012, 1206.5347.

[31]  S. Seager,et al.  A Unique Solution of Planet and Star Parameters from an Extrasolar Planet Transit Light Curve , 2002, astro-ph/0206228.

[32]  A. P. S. Fellow,et al.  150 new transiting planet candidates from Kepler Q1–Q6 data , 2012, 1205.6492.