Thermal Phase Variations of WASP-12b: Defying Predictions

[Abridged] We report Warm Spitzer full-orbit phase observations of WASP-12b at 3.6 and 4.5 micron. We are able to measure the transit depths, eclipse depths, thermal and ellipsoidal phase variations at both wavelengths. The large amplitude phase variations, combined with the planet's previously-measured day-side spectral energy distribution, is indicative of non-zero Bond albedo and very poor day-night heat redistribution. The transit depths in the mid-infrared indicate that the atmospheric opacity is greater at 3.6 than at 4.5 micron, in disagreement with model predictions, irrespective of C/O ratio. The secondary eclipse depths are consistent with previous studies. We do not detect ellipsoidal variations at 3.6 micron, but our parameter uncertainties -estimated via prayer-bead Monte Carlo- keep this non-detection consistent with model predictions. At 4.5 micron, on the other hand, we detect ellipsoidal variations that are much stronger than predicted. If interpreted as a geometric effect due to the planet's elongated shape, these variations imply a 3:2 ratio for the planet's longest:shortest axes and a relatively bright day-night terminator. If we instead presume that the 4.5 micron ellipsoidal variations are due to uncorrected systematic noise and we fix the amplitude of the variations to zero, the best fit 4.5 micron transit depth becomes commensurate with the 3.6 micron depth, within the uncertainties. The relative transit depths are then consistent with a Solar composition and short scale height at the terminator. Assuming zero ellipsoidal variations also yields a much deeper 4.5 micron eclipse depth, consistent with a Solar composition and modest temperature inversion. We suggest future observations that could distinguish between these two scenarios.Comment: 19 pages, 10 figures, ApJ in press. Improved discussion of gravity brightenin

Spitzer IRAC Secondary Eclipse Photometry of the Transiting Extrasolar Planet HAT-P-1b

We report Spitzer/IRAC photometry of the transiting giant exoplanet HAT-P-1b during its secondary eclipse. This planet lies near the postulated boundary between the pM and pL-class of hot Jupiters, and is important as a test of models for temperature inversions in hot Jupiter atmospheres. We derive eclipse depths for HAT-P-1b, in units of the stellar flux, that are: 0.080% +/- 0.008%,[3.6um], 0.135% +/- 0.022%,[4.5um],0.203% +/- 0.031%,[5.8um], and $0.238% +/- 0.040%,[8.0um]. These values are best fit using an atmosphere with a modest temperature inversion, intermediate between the archetype inverted atmosphere (HD209458b) and a model without an inversion. The observations also suggest that this planet is radiating a large fraction of the available stellar irradiance on its dayside, with little available for redistribution by circulation. This planet has sometimes been speculated to be inflated by tidal dissipation, based on its large radius in discovery observations, and on a non-zero orbital eccentricity allowed by the radial velocity data. The timing of the secondary eclipse is very sensitive to orbital eccentricity, and we find that the central phase of the eclipse is 0.4999 +/- 0.0005. The difference between the expected and observed phase indicates that the orbit is close to circular, with a 3-sigma limit of |e cosw| < 0.002.Comment: 5 pages, 6 figures, 1 table. Accepted by The Astrophysical Journal, 10 Nov 200

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

Interferons Regulate the Phenotype of Wild-type and Mutant Herpes Simplex Viruses In Vivo

Mechanisms responsible for neuroattenuation of herpes simplex virus (HSV) have been defined previously by studies of mutant viruses in cultured cells. The hypothesis that null mutations in host genes can override the attenuated phenotype of null mutations in certain viral genes was tested. Mutants such as those in infected cell protein (ICP) 0, thymidine kinase, ribonucleotide reductase, virion host shutoff, and ICP34.5 are reduced in their capacity to replicate in nondividing cells in culture and in vivo. The replication of these viruses was examined in eyes and trigeminal ganglia for 1–7 d after corneal inoculation in mice with null mutations (−/−) in interferon receptors (IFNR) for type I IFNs (IFN-α/βR), type II IFN (IFN-γR), and both type I and type II IFNs (IFN-α/β/γR). Viral titers in eyes and ganglia of IFN-γR−/− mice were not significantly different from congenic controls. However, in IFN-α/βR−/− or IFN-α/β/γR−/− mice, growth of all mutants, including those with significantly impaired growth in cell culture, was enhanced by up to 1,000-fold in eyes and trigeminal ganglia. Blepharitis and clinical signs of infection were evident in IFN-α/βR−/− and IFN-α/β/γR−/− but not control mice for all viruses. Also, IFNs were shown to significantly reduce productive infection of, and spread from intact, but not scarified, corneas. Particularly striking was restoration of near-normal trigeminal ganglion replication and neurovirulence of an ICP34.5 mutant in IFN-α/βR−/− mice. These data show that IFNs play a major role in limiting mutant and wild-type HSV replication in the cornea and in the nervous system. In addition, the in vivo target of ICP34.5 may be host IFN responses. These experiments demonstrate an unsuspected role for host factors in defining the phenotypes of some HSV mutants in vivo. The phenotypes of mutant viruses therefore cannot be interpreted based solely upon studies in cell culture but must be considered carefully in the context of host factors that may define the in vivo phenotype

XO-5b: A Transiting Jupiter-sized Planet With A Four Day Period

The star XO-5 (GSC 02959-00729, V=12.1, G8V) hosts a Jupiter-sized, Rp=1.15+/-0.12 Rjup, transiting extrasolar planet, XO-5b, with an orbital period of P=4.187732+/-0.00002 days. The planet mass (Mp=1.15+/-0.08 Mjup) and surface gravity (gp=22+/-5 m/s^2) are significantly larger than expected by empirical Mp-P and Mp-P-[Fe/H] relationships. However, the deviation from the Mp-P relationship for XO-5b is not large enough to suggest a distinct type of planet as is suggested for GJ 436b, HAT-P-2b, and XO-3b. By coincidence XO-5 overlies the extreme H I plume that emanates from the interacting galaxy pair NGC 2444/NGC 2445 (Arp 143).Comment: 10 pages, 9 Figures, Submitted to Ap

The XO Planetary Survey Project - Astrophysical False Positives

Searches for planetary transits find many astrophysical false positives as a by-product. There are four main types analyzed in the literature: a grazing-incidence eclipsing binary star, an eclipsing binary star with a small radius companion star, a blend of one or more stars with an unrelated eclipsing binary star, and a physical triple star system. We present a list of 69 astrophysical false positives that had been identified as candidates of transiting planets of the on-going XO survey. This list may be useful in order to avoid redundant observation and characterization of these particular candidates independently identified by other wide-field searches for transiting planets. The list may be useful for those modeling the yield of the XO survey and surveys similar to it. Subsequent observations of some of the listed stars may improve mass-radius relations, especially for low-mass stars. From the candidates exhibiting eclipses, we report three new spectroscopic double-line binaries and give mass function estimations for 15 single lined spectroscopic binaries.Comment: 13 pages, 4 figures, accepted to ApJ

Thermal Emission of WASP-14b Revealed with Three Spitzer Eclipses

Exoplanet WASP-14b is a highly irradiated, transiting hot Jupiter. Joshi et al. calculate an equilibrium temperature Teq of 1866 K for zero albedo and reemission from the entire planet, a mass of 7.3 +/- 0.5 Jupiter masses and a radius of 1.28 +/- 0.08 Jupiter radii. Its mean density of 4.6 g/cm3 is one of the highest known for planets with periods less than 3 days. We obtained three secondary eclipse light curves with the Spitzer Space Telescope. The eclipse depths from the best jointly fit model are $0.224\%$ +/- $0.018\%$ at 4.5 {\mu}m and $0.181\%$ +/- $0.022\%$ at 8.0 {\mu}m. The corresponding brightness temperatures are 2212 +/- 94 K and 1590 +/- 116 K. A slight ambiguity between systematic models suggests a conservative 3.6 {\mu}m eclipse depth of $0.19\%$ +/- $0.01\%$ and brightness temperature of 2242 +/- 55 K. Although extremely irradiated, WASP-14b does not show any distinct evidence of a thermal inversion. In addition, the present data nominally favor models with day night energy redistribution less than $~30\%$. The current data are generally consistent with oxygen-rich as well as carbon-rich compositions, although an oxygen-rich composition provides a marginally better fit. We confirm a significant eccentricity of e = 0.087 +/- 0.002 and refine other orbital parameters.Comment: 16 pages, 16 figure

Secondary Eclipse Photometry of WASP-4b with Warm Spitzer

We present photometry of the giant extrasolar planet WASP-4b at 3.6 and 4.5 micron taken with the Infrared Array Camera on board the Spitzer Space Telescope as part of Spitzer's extended warm mission. We find secondary eclipse depths of 0.319+/-0.031% and 0.343+/-0.027% for the 3.6 and 4.5 micron bands, respectively and show model emission spectra and pressure-temperature profiles for the planetary atmosphere. These eclipse depths are well fit by model emission spectra with water and other molecules in absorption, similar to those used for TrES-3 and HD 189733b. Depending on our choice of model, these results indicate that this planet has either a weak dayside temperature inversion or no inversion at all. The absence of a strong thermal inversion on this highly irradiated planet is contrary to the idea that highly irradiated planets are expected to have inversions, perhaps due the presence of an unknown absorber in the upper atmosphere. This result might be explained by the modestly enhanced activity level of WASP-4b's G7V host star, which could increase the amount of UV flux received by the planet, therefore reducing the abundance of the unknown stratospheric absorber in the planetary atmosphere as suggested in Knutson et al. (2010). We also find no evidence for an offset in the timing of the secondary eclipse and place a 2 sigma upper limit on |ecos(omega)| of 0.0024, which constrains the range of tidal heating models that could explain this planet's inflated radius.Comment: 8 pages, 7 figures (some in color), accepted for publication in Ap

Effect on genital warts in Australian female and heterosexual male individuals after introduction of the national human papillomavirus gender-neutral vaccination programme: an analysis of national sentinel surveillance data from 2004–18

Background: In Australia, the government-funded human papillomavirus (HPV) vaccination programme was introduced in April, 2007, for girls and young women, and in February, 2013, for boys. As of Dec 31, 2018, all Australian-born female individuals younger than 38 years and male individuals younger than 21 years have been eligible for the free quadrivalent or nonavalent HPV vaccine. We aimed to examine the trends in genital wart diagnoses among Australian-born female and heterosexual male individuals who attended sexual health clinics throughout Australia before and after the introduction of the gender-neutral HPV vaccination programme in February, 2013. Methods: We did a serial cross-sectional analysis of genital wart diagnoses among Australian-born female and heterosexual male individuals attending a national surveillance network of 35 clinics between Jan 1, 2004, and Dec 31, 2018. We calculated prevalence ratios of genital warts, using log-binomial regression models, for the female-only vaccination period (July 1, 2007, to Feb 28, 2013), gender-neutral vaccination period (March 1, 2013, to Dec 31, 2018), and the whole vaccination period (July 1, 2007, to Dec 31, 2018) compared with the pre-vaccination period (Jan 1, 2004, to June 30, 2007). Findings: We included 121 038 men and 116 341 women in the analysis. Overall, we observed a 58% reduction (prevalence ratio 0·42, 95% CI 0·40–0·44) in genital wart diagnoses in female individuals and a 45% reduction (0·55, 0·53–0·57) in genital wart diagnoses in heterosexual male individuals after the introduction of the vaccination programme in 2007. The largest reduction in genital warts was observed in younger individuals, and there was a decreasing magnitude of reduction with increasing age (80%, 72%, 61%, 41%, and 16% reductions in female individuals aged 15–20 years, 21–25 years, 26–30 years, 31–35 years, and ≥36 years, respectively; 70%, 61%, 49%, 37%, and 29% reductions in male individuals aged 15–20 years, 21–25 years, 26–30 years, 31–35 years, and ≥36 years, respectively). Significant reductions observed in female individuals (0·32, 0·28–0·36) and male individuals (0·51, 0·43–0·61) aged 15–20 years in the female-only vaccination period were followed by a more substantial reduction in female individuals (0·07, 0·06–0·09) and male individuals (0·11, 0·08–0·15) aged 15–20 years in the gender-neutral vaccination period. Interpretation: The national gender-neutral HPV vaccination programme has led to substantial and ongoing reduction in genital warts among Australian female and heterosexual male individuals, with a marked reduction in young individuals who received the vaccine at school. Funding: Seqirus Australia and the Australian Government Department of Health