1,610 research outputs found
A Correlation Between Stellar Activity and Hot Jupiter Emission Spectra
We present evidence for a correlation between the observed properties of hot
Jupiter emission spectra and the activity levels of the host stars measured
using Ca II H & K emission lines. We find that planets with dayside emission
spectra that are well-described by standard 1D atmosphere models with water in
absorption (HD 189733, TrES-1, TrES-3, WASP-4) orbit chromospherically active
stars, while planets with emission spectra that are consistent with the
presence of a strong high-altitude temperature inversion and water in emission
orbit quieter stars. We estimate that active G and K stars have Lyman alpha
fluxes that are typically a factor of 4-7 times higher than quiet stars with
analogous spectral types, and propose that the increased UV flux received by
planets orbiting active stars destroys the compounds responsible for the
formation of the observed temperature inversions. In this paper we also derive
a model-independent method for differentiating between these two atmosphere
types using the secondary eclipse depths measured in the 3.6 and 4.5 micron
bands on the Spitzer Space Telescope, and argue that the observed correlation
is independent of the inverted/non-inverted paradigm for classifying hot
Jupiter atmospheres.Comment: 9 pages, 5 figures, accepted for publication in ApJ. The updated
paper includes spectra for ten additional systems and a new section
discussing the connection between chromospheric activity and UV flu
Ethnic conflict between the Siamese and the Mon, Hmong and Malay-Muslims of Thailand : a comparison of religion, language and ethnic rank
In my paper I discuss the ethnic conflict among the Siamese majority and the minority. Due to the amount of ethnic diversity I limited my research to three groups: The Mon, Hmong and the Malays of Southern Thailand. Within these groups my parameters were religion, language and ethnic rank. These groups also illustrate various degrees of ethnic conflict. I comment that religion and the use of Thai language is very important in being Thai by Thai standards. Ethnic rank also relates to the awareness of being Thai. Because of the lack of information of these subjects, I comment that more research and study must be done in order to fully understand the problem
The SXS Collaboration catalog of binary black hole simulations
Accurate models of gravitational waves from merging black holes are necessary
for detectors to observe as many events as possible while extracting the
maximum science. Near the time of merger, the gravitational waves from merging
black holes can be computed only using numerical relativity. In this paper, we
present a major update of the Simulating eXtreme Spacetimes (SXS) Collaboration
catalog of numerical simulations for merging black holes. The catalog contains
2018 distinct configurations (a factor of 11 increase compared to the 2013 SXS
catalog), including 1426 spin-precessing configurations, with mass ratios
between 1 and 10, and spin magnitudes up to 0.998. The median length of a
waveform in the catalog is 39 cycles of the dominant
gravitational-wave mode, with the shortest waveform containing 7.0 cycles and
the longest 351.3 cycles. We discuss improvements such as correcting for moving
centers of mass and extended coverage of the parameter space. We also present a
thorough analysis of numerical errors, finding typical truncation errors
corresponding to a waveform mismatch of . The simulations provide
remnant masses and spins with uncertainties of 0.03% and 0.1% (
percentile), about an order of magnitude better than analytical models for
remnant properties. The full catalog is publicly available at
https://www.black-holes.org/waveforms .Comment: 33+18 pages, 13 figures, 4 tables, 2,018 binaries. Catalog metadata
in ancillary JSON file. v2: Matches version accepted by CQG. Catalog
available at https://www.black-holes.org/waveform
Atmospheric observation-based estimation of fossil fuel CO_2 emissions from regions of central and southern California
Combustion of fossil fuel is the dominant source of greenhouse gas emissions to the atmosphere in California. Here, we describe radiocarbon (^(14)CO_2) measurements and atmospheric inverse modeling to estimate fossil fuel CO_2 (ffCO_2) emissions for 2009–2012 from a site in central California, and for June 2013–May 2014 from two sites in southern California. A priori predicted ffCO_2 mixing ratios are computed based on regional atmospheric transport model (WRF-STILT) footprints and an hourly ffCO_2 prior emission map (Vulcan 2.2). Regional inversions using observations from the central California site suggest that emissions from the San Francisco Bay Area (SFBA) are higher in winter and lower in summer. Taking all years together, the average of a total of fifteen 3-month inversions from 2009 to 2012 suggests ffCO_2 emissions from SFBA were within 6 ± 35% of the a priori estimate for that region, where posterior emission uncertainties are reported as 95% confidence intervals. Results for four 3-month inversions using measurements in Los Angeles South Coast Air Basin (SoCAB) during June 2013–May 2014 suggest that emissions in SoCAB are within 13 ± 28% of the a priori estimate for that region, with marginal detection of any seasonality. While emissions from the SFBA and SoCAB urban regions (containing ~50% of prior emissions from California) are constrained by the observations, emissions from the remaining regions are less constrained, suggesting that additional observations will be valuable to more accurately estimate total ffCO_2 emissions from California as a whole
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Refining the accuracy of validated target identification through coding variant fine-mapping in type 2 diabetes.
We aggregated coding variant data for 81,412 type 2 diabetes cases and 370,832 controls of diverse ancestry, identifying 40 coding variant association signals (P < 2.2 × 10-7); of these, 16 map outside known risk-associated loci. We make two important observations. First, only five of these signals are driven by low-frequency variants: even for these, effect sizes are modest (odds ratio ≤1.29). Second, when we used large-scale genome-wide association data to fine-map the associated variants in their regional context, accounting for the global enrichment of complex trait associations in coding sequence, compelling evidence for coding variant causality was obtained for only 16 signals. At 13 others, the associated coding variants clearly represent 'false leads' with potential to generate erroneous mechanistic inference. Coding variant associations offer a direct route to biological insight for complex diseases and identification of validated therapeutic targets; however, appropriate mechanistic inference requires careful specification of their causal contribution to disease predisposition
The N2K Consortium. III. Short-Period Planets Orbiting HD 149143 and HD 109749
We report the detection of two short-period planets discovered at Keck Observatory. HD 149143 is a metal-rich G0 IV star with a planet of M sin i = 1.33M_J and an orbital radius of 0.053 AU. The best-fit Keplerian model has an orbital period, P = 4.072 days, semivelocity amplitude, K = 149.6 m s^(-1), and eccentricity, e = 0.016 ± 0.01. The host star is chromospherically inactive and metal-rich, with [Fe/H] = 0.26. Based on the T_(eff) and stellar luminosity, we derive a stellar radius of 1.49 R_☉. Photometric observations of HD 149143 were carried out using the automated photometric telescopes at Fairborn Observatory. HD 149143 is photometrically constant over the radial velocity period to 0.0003 ± 0.0002 mag, supporting the existence of the planetary companion. No transits were detected down to a photometric limit of approximately 0.02%, eliminating transiting planets with a variety of compositions and constraining the orbital inclination to less than 83°. A short-period planet was also detected around HD 109749, a G3 IV star. HD 109749 is chromospherically inactive, with [Fe/H] = 0.25 and a stellar radius of 1.24. The radial velocities for HD 109749 are modeled by a Keplerian with P = 5.24 days and K = 28.7 m s^(-1). The inferred planet mass is M sin i = 0.28M_J and the semimajor axis of this orbit is 0.0635 AU. Photometry of HD 109749 was obtained with the SMARTS consortium telescope, the PROMPT telescope, and by transitsearch.org observers in Adelaide and Pretoria. These observations did not detect a decrement in the brightness of the host star at the predicted ephemeris time, and they constrain the orbital inclination to less than 85° for gas giant planets with radii down to 0.7R_J
The Business Case for Responsible Corporate Adaptation: Strengthening Private Sector and Community Resilience.:A Caring for Climate Report
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