Ground-based near-IR observations of the secondary eclipse of CoRoT-2b

We present the results of a ground-based search for the secondary eclipse of the 3.3 Mjup transiting planet CoRoT-2b. We performed near infrared photometry using the LIRIS instrument on the 4.2 m William Herschel Telescope, in the H and K_s filters. We monitored the star around two expected secondary eclipses in two nights under very good observing conditions. For the depth of the secondary eclipse we find in H-band a 3 sigma upper limit of 0.17%, whereas we detected a tentative eclipse with a depth of 0.16+-0.09% in the K_s-band. These depths can be translated into brightness temperatures of T_H<2250 K and T_{K_s} = 1890(+260-350) K, which indicate an inefficient re-distribution of the incident stellar flux from the planet's dayside to its nightside. Our results are in agreement with the CoRoT optical measurement (Alonso et al. 09) and with Spitzer 4.5 and 8 micron results (Gillon et al. 09c).Comment: Astronomical Journal, accepte

Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands

We find that a theoretical fit to all the HD 209458b data at secondary eclipse requires that the dayside atmosphere of HD 209458b have a thermal inversion and a stratosphere. This inversion is caused by the capture of optical stellar flux by an absorber of uncertain origin that resides at altitude. One consequence of stratospheric heating and temperature inversion is the flipping of water absorption features into emission features from the near- to the mid-infrared and we see evidence of such a water emission feature in the recent HD 209458b IRAC data of Knutson et al. In addition, an upper-atmosphere optical absorber may help explain both the weaker-than-expected Na D feature seen in transit and the fact that the transit radius at 24 $\mu$m is smaller than the corresponding radius in the optical. Moreover, it may be a factor in why HD 209458b's optical transit radius is as large as it is. We speculate on the nature of this absorber and the planets whose atmospheres may, or may not, be affected by its presence.Comment: Accepted to the Astrophysical Journal Letters on August 28, 2007, six pages in emulateapj forma

The Affective Impact of Financial Skewness on Neural Activity and Choice

Few finance theories consider the influence of “skewness” (or large and asymmetric but unlikely outcomes) on financial choice. We investigated the impact of skewed gambles on subjects' neural activity, self-reported affective responses, and subsequent preferences using functional magnetic resonance imaging (FMRI). Neurally, skewed gambles elicited more anterior insula activation than symmetric gambles equated for expected value and variance, and positively skewed gambles also specifically elicited more nucleus accumbens (NAcc) activation than negatively skewed gambles. Affectively, positively skewed gambles elicited more positive arousal and negatively skewed gambles elicited more negative arousal than symmetric gambles equated for expected value and variance. Subjects also preferred positively skewed gambles more, but negatively skewed gambles less than symmetric gambles of equal expected value. Individual differences in both NAcc activity and positive arousal predicted preferences for positively skewed gambles. These findings support an anticipatory affect account in which statistical properties of gambles—including skewness—can influence neural activity, affective responses, and ultimately, choice

A Revised List of the Orthoptera of Iowa

The first list of Iowa Orthoptera was entitled A Preliminary Catalogue of the Orthoptera of Iowa. This was published by C. E. Bessey in the Seventh Biennial Report of the Iowa State College in 1877. The list included about forty species

Transits and secondary eclipses of HD 189733 with Spitzer

We present limits on transit timing variations and secondary eclipse depth variations at 8 microns with the Spitzer Space Telescope IRAC camera. Due to the weak limb darkening in the infrared and uninterrupted observing, Spitzer provides the highest accuracy transit times for this bright system, in principle providing sensitivity to secondary planets of Mars mass in resonant orbits. Finally, the transit data provides tighter constraints on the wavelength- dependent atmospheric absorption by the planet.Comment: 7 pages, 7 figures, submitted to proceedings of IAU Symposium No. 253 "Transiting Planets

Hubble Space Telescope Transmission Spectroscopy of the Exoplanet HD 189733b: High-altitude atmospheric haze in the optical and near-UV with STIS

We present Hubble Space Telescope optical and near-ultraviolet transmission spectra of the transiting hot-Jupiter HD189733b, taken with the repaired Space Telescope Imaging Spectrograph (STIS) instrument. The resulting spectra cover the range 2900-5700 Ang and reach per-exposure signal-to-noise levels greater than 11,000 within a 500 Ang bandwidth. We used time series spectra obtained during two transit events to determine the wavelength dependance of the planetary radius and measure the exoplanet's atmospheric transmission spectrum for the first time over this wavelength range. Our measurements, in conjunction with existing HST spectra, now provide a broadband transmission spectrum covering the full optical regime. The STIS data also shows unambiguous evidence of a large occulted stellar spot during one of our transit events, which we use to place constraints on the characteristics of the K dwarf's stellar spots, estimating spot temperatures around Teff~4250 K. With contemporaneous ground-based photometric monitoring of the stellar variability, we also measure the correlation between the stellar activity level and transit-measured planet-to-star radius contrast, which is in good agreement with predictions. We find a planetary transmission spectrum in good agreement with that of Rayleigh scattering from a high-altitude atmospheric haze as previously found from HST ACS camera. The high-altitude haze is now found to cover the entire optical regime and is well characterised by Rayleigh scattering. These findings suggest that haze may be a globally dominant atmospheric feature of the planet which would result in a high optical albedo at shorter optical wavelengths.Comment: 14 pages, 14 figures, 4 tables, accepted to MNRAS, revised version has minor change

Future changes in tropical cyclone activity in the North Indian Ocean projected by high-resolution MRI-AGCMs

Open Access at publisher's web site: http://www.springerlink.com/content/b682734237171631