878 research outputs found
Violence in Ming-Qing China : An Overview
Let us begin with a basic fact : the level of violence in late imperial China was probably as high as that in any historical society in the world. Obvious as this may sound, it is easy to miss it. The entire central message of the package of literati values that we refer to as ‘Confucianism’, and especially after its elaboration into the so-called ‘school of principle’ or ‘neo-Confucianism’ (lixue) after the eleventh century CE, was certainly more energetic than most elite cultures in esteemi..
Kepler Observations of the Three Pre-Launch Exoplanet Candidates: Discover of Two Eclipsing Binaries and a New Exoplanet
Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter 1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 R_(Jupiter) in a 3.9 day orbit
Transit Timing Observations from Kepler: VI. Potentially interesting candidate systems from Fourier-based statistical tests
We analyze the deviations of transit times from a linear ephemeris for the
Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We
conduct two statistical tests for all KOIs and a related statistical test for
all pairs of KOIs in multi-transiting systems. These tests identify several
systems which show potentially interesting transit timing variations (TTVs).
Strong TTV systems have been valuable for the confirmation of planets and their
mass measurements. Many of the systems identified in this study should prove
fruitful for detailed TTV studies.Comment: 32 pages, 6 of text and one long table, Accepted to Ap
Detection Of KOI-13.01 Using The Photometric Orbit
We use the KOI-13 transiting star-planet system as a test case for the
recently developed BEER algorithm (Faigler & Mazeh 2011), aimed at identifying
non-transiting low-mass companions by detecting the photometric variability
induced by the companion along its orbit. Such photometric variability is
generated by three mechanisms, including the beaming effect, tidal ellipsoidal
distortion, and reflection/heating. We use data from three Kepler quarters,
from the first year of the mission, while ignoring measurements within the
transit and occultation, and show that the planet's ephemeris is clearly
detected. We fit for the amplitude of each of the three effects and use the
beaming effect amplitude to estimate the planet's minimum mass, which results
in M_p sin i = 9.2 +/- 1.1 M_J (assuming the host star parameters derived by
Szabo et al. 2011). Our results show that non-transiting star-planet systems
similar to KOI-13.01 can be detected in Kepler data, including a measurement of
the orbital ephemeris and the planet's minimum mass. Moreover, we derive a
realistic estimate of the amplitudes uncertainties, and use it to show that
data obtained during the entire lifetime of the Kepler mission, of 3.5 years,
will allow detecting non-transiting close-in low-mass companions orbiting
bright stars, down to the few Jupiter mass level. Data from the Kepler Extended
Mission, if funded by NASA, will further improve the detection capabilities.Comment: Accepted to AJ on October 4, 2011. Kepler Q5 Long Cadence data will
become publicly available on MAST by October 23. Comments welcome (V2: minor
changes, to reflect proof corrections
Ancilla-based quantum simulation
We consider simulating the BCS Hamiltonian, a model of low temperature
superconductivity, on a quantum computer. In particular we consider conducting
the simulation on the qubus quantum computer, which uses a continuous variable
ancilla to generate interactions between qubits. We demonstrate an O(N^3)
improvement over previous work conducted on an NMR computer [PRL 89 057904
(2002) & PRL 97 050504 (2006)] for the nearest neighbour and completely general
cases. We then go on to show methods to minimise the number of operations
needed per time step using the qubus in three cases; a completely general case,
a case of exponentially decaying interactions and the case of fixed range
interactions. We make these results controlled on an ancilla qubit so that we
can apply the phase estimation algorithm, and hence show that when N \geq 5,
our qubus simulation requires significantly less operations that a similar
simulation conducted on an NMR computer.Comment: 20 pages, 10 figures: V2 added section on phase estimation and
performing controlled unitaries, V3 corrected minor typo
Validation of Kepler's Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems
The Kepler mission has discovered over 2500 exoplanet candidates in the first
two years of spacecraft data, with approximately 40% of them in candidate
multi-planet systems. The high rate of multiplicity combined with the low rate
of identified false-positives indicates that the multiplanet systems contain
very few false-positive signals due to other systems not gravitationally bound
to the target star (Lissauer, J. J., et al., 2012, ApJ 750, 131). False
positives in the multi- planet systems are identified and removed, leaving
behind a residual population of candidate multi-planet transiting systems
expected to have a false-positive rate less than 1%. We present a sample of 340
planetary systems that contain 851 planets that are validated to substantially
better than the 99% confidence level; the vast majority of these have not been
previously verified as planets. We expect ~2 unidentified false-positives
making our sample of planet very reliable. We present fundamental planetary
properties of our sample based on a comprehensive analysis of Kepler light
curves and ground-based spectroscopy and high-resolution imaging. Since we do
not require spectroscopy or high-resolution imaging for validation, some of our
derived parameters for a planetary system may be systematically incorrect due
to dilution from light due to additional stars in the photometric aperture.
None the less, our result nearly doubles the number of verified exoplanets.Comment: 138 pages, 8 Figures, 5 Tables. Accepted for publications in the
Astrophysical Journa
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