101 research outputs found
Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data
New transiting planet candidates are identified in sixteen months (May 2009 -
September 2010) of data from the Kepler spacecraft. Nearly five thousand
periodic transit-like signals are vetted against astrophysical and instrumental
false positives yielding 1,091 viable new planet candidates, bringing the total
count up to over 2,300. Improved vetting metrics are employed, contributing to
higher catalog reliability. Most notable is the noise-weighted robust averaging
of multi-quarter photo-center offsets derived from difference image analysis
which identifies likely background eclipsing binaries. Twenty-two months of
photometry are used for the purpose of characterizing each of the new
candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are
tabulated as well as the products of light curve modeling: reduced radius
(Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest
fractional increases are seen for the smallest planet candidates (197% for
candidates smaller than 2Re compared to 52% for candidates larger than 2Re) and
those at longer orbital periods (123% for candidates outside of 50-day orbits
versus 85% for candidates inside of 50-day orbits). The gains are larger than
expected from increasing the observing window from thirteen months (Quarter 1--
Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the
benefit of continued development of pipeline analysis software. The fraction of
all host stars with multiple candidates has grown from 17% to 20%, and the
paucity of short-period giant planets in multiple systems is still evident. The
progression toward smaller planets at longer orbital periods with each new
catalog release suggests that Earth-size planets in the Habitable Zone are
forthcoming if, indeed, such planets are abundant.Comment: Submitted to ApJS. Machine-readable tables are available at
http://kepler.nasa.gov, http://archive.stsci.edu/kepler/results.html, and the
NASA Exoplanet Archiv
Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets
We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R ⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
We present K band spectra for 133 nearby (d < 33 parsecs) M dwarfs, including
18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type
companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the
Northern 8 pc sample, and several M dwarfs from the LSPM catalog. From these
spectra, we measure equivalent widths of the Ca and Na lines, and a spectral
index quantifying the absorption due to H2O opacity (the H2O-K2 index). Using
empirical spectral types standards and synthetic models, we calibrate the
H2O-K2 index as an indicator of an M dwarf's spectral type and effective
temperature. We also present a revised relationship that estimates the [Fe/H]
and [M/H] metallicities of M dwarfs from their Na I, Ca I, and H2O-K2
measurements. Comparisons to model atmosphere provide a qualitative validation
of our approach, but also reveal an overall offset between the atomic line
strengths predicted by models as compared to actual observations. Our
metallicity estimates also reproduce expected correlations with Galactic space
motions and H alpha emission line strengths, and return statistically identical
metallicities for M dwarfs within a common multiple system. Finally, we find
systematic residuals between our H2O-based spectral types and those derived
from optical spectral features with previously known sensitivity to stellar
metallicity, such as TiO, and identify the CaH1 index as a promising optical
index for diagnosing the metallicities of near-solar M dwarfs.Comment: 132 pages, 48 figures. Paper resubmitted to Ap
A few remarks on colour-flavour transformations, truncations of random unitary matrices, Berezin reproducing kernels and Selberg-type integrals
The Humboldt Foundation is acknowledged for the financial support of that visit. The research in Nottingham was supported by EPSRC grant EP/C515056/1 'Random Matrices and Polynomials: a tool to understand complexity'
Acridine dye and its nucleotide derivative. Analysis of chemical equilibria in aqueous solution using relaxation amplitudes of temperature jump
Raman spectral study of the Mg(ClO4)2NaNCSH2O system at ambient and elevated temperatures
The effect of ion-site interactions on the apparent molal volume of polystyrenesulfonic acid and its salts in aqueous solutions
An immunologically relevant rodent model demonstrates safety of therapy using a tumour-specific IgE
Antixenosis and larval and adult dispersal in the Mediterranean corn borer, Sesamia nonagrioides
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