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Kepler-4B: A Hot Neptune-Like Planet of A G0 Star Near Main-Sequence Turnoff
Early time-series photometry from NASA's Kepler spacecraft has revealed a planet transiting the star we term Kepler-4, at R.A. = 19(h)02(m)27.(s)68, delta = +50 degrees 08'08 '' 7. The planet has an orbital period of 3.213 days and shows transits with a relative depth of 0.87 x 10(-3) and a duration of about 3.95 hr. Radial velocity (RV) measurements from the Keck High Resolution Echelle Spectrometer show a reflex Doppler signal of 9.3(-1.9)(+1.1) m s(-1), consistent with a low-eccentricity orbit with the phase expected from the transits. Various tests show no evidence for any companion star near enough to affect the light curve or the RVs for this system. From a transit-based estimate of the host star's mean density, combined with analysis of high-resolution spectra, we infer that the host star is near turnoff from the main sequence, with estimated mass and radius of 1.223(-0.091)(+0.053) M(circle dot) and 1.487(-0.084)(+0.071) R(circle dot).We estimate the planet mass and radius to be {M(P), R(P)} = {24.5 +/- 3.8 M(circle plus), 3.99 +/- 0.21 R(circle plus)}. The planet's density is near 1.9 g cm(-3); it is thus slightly denser and more massive than Neptune, but about the same size.W. M. Keck FoundationNASA's Science Mission DirectorateAstronom
Kepler-7b: A Transiting Planet with Unusually Low Density
We report the discovery and confirmation of Kepler-7b, a transiting planet
with unusually low density. The mass is less than half that of Jupiter, Mp =
0.43 Mj, but the radius is fifty percent larger, Rp = 1.48 Rj. The resulting
density, 0.17 g/cc, is the second lowest reported so far for an extrasolar
planet. The orbital period is fairly long, P = 4.886 days, and the host star is
not much hotter than the Sun, Teff = 6000 K. However, it is more massive and
considerably larger than the sun, Mstar = 1.35 Msun and Rstar = 1.84 Rsun, and
must be near the end of its life on the Main Sequence.Comment: 19 pages, 3 figure
A Transiting Hot Jupiter Orbiting a Metal-Rich Star
We announce the discovery of Kepler-6b, a transiting hot Jupiter orbiting a
star with unusually high metallicity, [Fe/H] = +0.34 +/- 0.04. The planet's
mass is about 2/3 that of Jupiter, Mp = 0.67 Mj, and the radius is thirty
percent larger than that of Jupiter, Rp = 1.32 Rj, resulting in a density of
0.35 g/cc, a fairly typical value for such a planet. The orbital period is P =
3.235 days. The host star is both more massive than the Sun, Mstar = 1.21 Msun,
and larger than the Sun, Rstar = 1.39 Rsun.Comment: 12 pages, 2 figures, submitted to the Astrophysical Journal Letter
Non-Einstein geometries in Chiral Gravity
We analyze the asymptotic solutions of Chiral Gravity (Topologically Massive
Gravity at \mu l = 1 with Brown-Henneaux boundary conditions) focusing on
non-Einstein metrics. A class of such solutions admits curvature singularities
in the interior which are reflected as singularities or infinite bulk energy of
the corresponding linear solutions. A non-linear solution is found exactly. The
back-reaction induces a repulsion of geodesics and a shielding of the
singularity by an event horizon but also introduces closed timelike curves.Comment: 11 pages, 3 figures. v2: references and comments on linear stability
(Sect.2) adde
Risk factors for mesh/suture erosion following sacral colpopexy
To identify risks for mesh/suture erosions following sacrocolpopexy (ASC)
KOI-54: The Kepler Discovery of Tidally Excited Pulsations and Brightenings in a Highly Eccentric Binary
Kepler observations of the star HD 187091 (KIC 8112039, hereafter KOI-54) revealed a remarkable light curve exhibiting sharp periodic brightening events every 41.8 days with a superimposed set of oscillations forming a beating pattern in phase with the brightenings. Spectroscopic observations revealed that this is a binary star with a highly eccentric orbit, e = 0.83. We are able to match the Kepler light curve and radial velocities with a nearly face-on (i = 5 degrees.5) binary star model in which the brightening events are caused by tidal distortion and irradiation of nearly identical A stars during their close periastron passage. The two dominant oscillations in the light curve, responsible for the beating pattern, have frequencies that are the 91st and 90th harmonic of the orbital frequency. The power spectrum of the light curve, after removing the binary star brightening component, reveals a large number of pulsations, 30 of which have a signal-to-noise ratio greater than or similar to 7. Nearly all of these pulsations have frequencies that are either integer multiples of the orbital frequency or are tidally split multiples of the orbital frequency. This pattern of frequencies unambiguously establishes the pulsations as resonances between the dynamic tides at periastron and the free oscillation modes of one or both of the stars. KOI-54 is only the fourth star to show such a phenomenon and is by far the richest in terms of excited modes.NASA, Science Mission DirectorateNASA NNX08AR14GEuropean Research Council under the European Community 227224W.M. Keck FoundationMcDonald Observator
Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple system
Light curves from the Kepler Mission contain valuable information on the
nature of the phenomena producing the transit-like signals. To assist in
exploring the possibility that they are due to an astrophysical false positive,
we describe a procedure (BLENDER) to model the photometry in terms of a "blend"
rather than a planet orbiting a star. A blend may consist of a background or
foreground eclipsing binary (or star-planet pair) whose eclipses are attenuated
by the light of the candidate and possibly other stars within the photometric
aperture. We apply BLENDER to the case of Kepler-9, a target harboring two
previously confirmed Saturn-size planets (Kepler-9b and Kepler-9c) showing
transit timing variations, and an additional shallower signal with a 1.59-day
period suggesting the presence of a super-Earth-size planet. Using BLENDER
together with constraints from other follow-up observations we are able to rule
out all blends for the two deeper signals, and provide independent validation
of their planetary nature. For the shallower signal we rule out a large
fraction of the false positives that might mimic the transits. The false alarm
rate for remaining blends depends in part (and inversely) on the unknown
frequency of small-size planets. Based on several realistic estimates of this
frequency we conclude with very high confidence that this small signal is due
to a super-Earth-size planet (Kepler-9d) in a multiple system, rather than a
false positive. The radius is determined to be 1.64 (+0.19/-0.14) R(Earth), and
current spectroscopic observations are as yet insufficient to establish its
mass.Comment: 20 pages in emulateapj format, including 8 tables and 16 figures. To
appear in ApJ, 1 January 2010. Accepted versio
Reducing orbital eccentricity in binary black hole simulations
Binary black hole simulations starting from quasi-circular (i.e., zero radial
velocity) initial data have orbits with small but non-zero orbital
eccentricities. In this paper the quasi-equilibrium initial-data method is
extended to allow non-zero radial velocities to be specified in binary black
hole initial data. New low-eccentricity initial data are obtained by adjusting
the orbital frequency and radial velocities to minimize the orbital
eccentricity, and the resulting ( orbit) evolutions are compared with
those of quasi-circular initial data. Evolutions of the quasi-circular data
clearly show eccentric orbits, with eccentricity that decays over time. The
precise decay rate depends on the definition of eccentricity; if defined in
terms of variations in the orbital frequency, the decay rate agrees well with
the prediction of Peters (1964). The gravitational waveforms, which contain
cycles in the dominant l=m=2 mode, are largely unaffected by the
eccentricity of the quasi-circular initial data. The overlap between the
dominant mode in the quasi-circular evolution and the same mode in the
low-eccentricity evolution is about 0.99.Comment: 27 pages, 9 figures; various minor clarifications; accepted to the
"New Frontiers" special issue of CQ
A First Comparison of Kepler Planet Candidates in Single and Multiple Systems
In this letter we present an overview of the rich population of systems with
multiple candidate transiting planets found in the first four months of Kepler
data. The census of multiples includes 115 targets that show 2 candidate
planets, 45 with 3, 8 with 4, and 1 each with 5 and 6, for a total of 170
systems with 408 candidates. When compared to the 827 systems with only one
candidate, the multiples account for 17 percent of the total number of systems,
and a third of all the planet candidates. We compare the characteristics of
candidates found in multiples with those found in singles. False positives due
to eclipsing binaries are much less common for the multiples, as expected.
Singles and multiples are both dominated by planets smaller than Neptune; 69
+2/-3 percent for singles and 86 +2/-5 percent for multiples. This result, that
systems with multiple transiting planets are less likely to include a
transiting giant planet, suggests that close-in giant planets tend to disrupt
the orbital inclinations of small planets in flat systems, or maybe even to
prevent the formation of such systems in the first place.Comment: 13 pages, 13 figures, submitted to ApJ Letter
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