Vertical distribution of aerosols and hazes over Jupiter's great red spot and its surroundings in 2016 from HST/WFC3 imaging

In this work, we have analyzed images provided by the Hubble Space Telescope's Wide Field Camera 3 (HST/WFC3) in December 2016, with a spectral coverage from the ultraviolet to the near infrared. We have obtained the spectral reflectivity of the GRS and its surroundings, with particular emphasis on selected, dynamically interesting regions. A spectral characterization of the GRS area is performed following two different procedures: (a) in terms of Altitude/Opacity and Color Indices (AOI and CI); (b) by means of automatic spectral classification. We used the NEMESIS radiative transfer suite to retrieve the main atmospheric parameters (e.g., particle vertical and size distributions, refractive indices) that are able to explain the observed spectral reflectivity. The optimal a priori model atmosphere used for the retrievals is obtained from a grid of about 12,000 different atmospheric models, and choosing the one that best fits South Tropical Zone (STrZ) spectra and its observed limb-darkening. We conclude that the spectral reflectivity of the GRS area is well reproduced with the following layout: (a) a stratospheric haze with its base near the 100 mbar level, with optical depths at 900 nm of the order of unity and particles with a size of 0.3 μm; (b) a more vertically extended tropospheric haze, with τ (900 nm) ∼10 down to 500 mbar and micron sized particles. Both haze layers show a stronger short wavelength absorption, and thus both act as chromophores. The altitude difference between clouds tops in the GRS and surrounding areas is ∼10 km

Color and aerosol changes in Jupiter after a North Temperate Belt disturbance

The banded appearance of Jupiter’s atmosphere shows significant changes over time, sometimes even transforming the reflectivity of a whole latitudinal band in a few weeks, and staying for years with an aspect different from the usual one. The origin of some of these disturbances may be associated with the creation and destruction of the chromophore species that provides Jovian clouds their reddish coloration. In this work, we have focused on the North Temperate Belt (NTB) disturbance detected during the second flyby of Juno mission (NASA) on October 2016, as a series of convective storms interacted with the fastest zonal jet on Jupiter at 24N over months and left a quiet belt characterized by an intense red coloration Sánchez-Lavega et al. (2017). In order to determine the corresponding changes in the upper clouds and hazes we have used images taken in 2016 and 2017 with the Hubble Space Telescope Wide Field Camera 3. Such images were acquired before and after the outbreak, showing an intense color change in a narrow latitude band. The images cover the wavelength range from 250 nm up to the methane absorption band at 890 nm, thus sensitive to a number of atmospheric levels from the lower stratosphere to the upper troposphere where the ammonia condensation cloud is expected to be located. Here we use the radiative transfer suite NEMESIS Irwin et al. (2008) to determine the vertical distribution and properties of the upper hazes that best match the observed dependence of reflectivity with wavelength and geometry. We use two models for the Jovian chromophore: (A) an extended layer whose imaginary refractive index is left as a free parameter; and (B) a concentrated chromophore as in Sromovsky et al. (2017) using the optical properties by Carlson et al. (2016). Both scenarios show an increase in the number of particles responsible for the blue absorption approximately by a factor of 2, and require only small changes in the rest of the atmospheric parameters. We find that, even though results provided by scenario B are also compatible with observations, the limb-darkening is better described by scenario A, where there is also an increase of the particle absorption at the shortest wavelengths. In this work, we also provide an extension of the expected imaginary refractive indices to wavelengths beyond those covered in previous laboratory works, which will be useful for future studies

Color and aerosol changes in Jupiter after a North Temperate Belt disturbance

International audienceThe banded appearance of Jupiter’s atmosphere shows significant changes over time, sometimes even transforming the reflectivity of a whole latitudinal band in a few weeks, and staying for years with an aspect different from the usual one. The origin of some of these disturbances may be associated with the creation and destruction of the chromophore species that provides Jovian clouds their reddish coloration. In this work, we have focused on the North Temperate Belt (NTB) disturbance detected during the second flyby of Juno mission (NASA) on October 2016, as a series of convective storms interacted with the fastest zonal jet on Jupiter at 24N over months and left a quiet belt characterized by an intense red coloration Sánchez-Lavega et al. (2017). In order to determine the corresponding changes in the upper clouds and hazes we have used images taken in 2016 and 2017 with the Hubble Space Telescope Wide Field Camera 3. Such images were acquired before and after the outbreak, showing an intense color change in a narrow latitude band. The images cover the wavelength range from 250 nm up to the methane absorption band at 890 nm, thus sensitive to a number of atmospheric levels from the lower stratosphere to the upper troposphere where the ammonia condensation cloud is expected to be located. Here we use the radiative transfer suite NEMESIS Irwin et al. (2008) to determine the vertical distribution and properties of the upper hazes that best match the observed dependence of reflectivity with wavelength and geometry. We use two models for the Jovian chromophore: (A) an extended layer whose imaginary refractive index is left as a free parameter; and (B) a concentrated chromophore as in Sromovsky et al. (2017) using the optical properties by Carlson et al. (2016). Both scenarios show an increase in the number of particles responsible for the blue absorption approximately by a factor of 2, and require only small changes in the rest of the atmospheric parameters. We find that, even though results provided by scenario B are also compatible with observations, the limb-darkening is better described by scenario A, where there is also an increase of the particle absorption at the shortest wavelengths. In this work, we also provide an extension of the expected imaginary refractive indices to wavelengths beyond those covered in previous laboratory works, which will be useful for future studies

Jupiter’s Great Red Spot: strong interactions with incoming anticyclones in 2019

Jupiter’s Great Red Spot (GRS), a giant anticyclone, is the largest and longest-lived of all the vortices observed in planetary atmospheres. During its history, the GRS has shrunk to half its size since 1879, and encountered many smaller anticyclones and other dynamical features that might tend to erode it. In 2018-2020, while having a historically small size, its structure and even its survival appeared to be threatened when a series of anticyclones moving in from the east tore off large fragments of the red area and distorted its shape. In this work we report observations of the dynamics of these interactions and show that as a result the GRS increased its internal rotation velocity, maintaining its vorticity but decreasing its visible area, and suffering a transient change in its otherwise steady 90-day oscillation in longitude. From a radiative transfer analysis and numerical simulations of the dynamics we show that the interactions affected the upper cloud tops of the GRS. We argue that the intense vorticity of the GRS, together with its larger size and depth compared to the interacting vortices, guarantees its long lifetime.This work has been supported by the Spanish project AYA2015-65041-P and PID2019-109467GB-I00 (MINECO/ FEDER, UE) and Grupos Gobierno Vasco IT1366-19. PI acknowledges a PhD scholarship from Gobierno Vasco. EGM is Serra Hunter Fellow at UPC. This work used data acquired from the NASA/ESA HST Space Telescope, asso- ciated with OPAL program (PI: Simon, GO13937), and archived by the Space Telescope Science Institute, which is operated by the Association of Universi- ties for Research in Astronomy, Inc., under NASA contract NAS 5–26,555. All maps are available at http://dx.doi. org/10.17909/T9G593. PlanetCam ob- servations were collected at the Centro Astronómico Hispánico en Andalucía (CAHA), operated jointly by the Insti- tuto de Astrofisica de Andalucia (CSIC) and the Andalusian Universities (Junta de Andalucía). EGM, MS, APG, MAC and ASL thankfully acknowledge the computer resources at Mare Nostrum and the technical support provided by Barcelona Supercomputing Center (AECT-2019-2-0006). This research has made use of the USGS Integrated Software for Imagers and Spectrometers (ISIS). We appreciate the contribution from all observers cited in TableS1 for his fundamental contribution to this study with Jupiter images obtained with high dedication and skill. GSO and TM were supported by NASA with funds distributed to the Jet Propulsion Laboratory, California Institute of Technology.Peer ReviewedPostprint (author's final draft

Properties and performance of the prototype instrument for the Pierre Auger Observatory

Copyright © 2003 Elsevier B.V. All rights reserved.Construction of the first stage of the Pierre Auger Observatory has begun. The aim of the Observatory is to collect unprecedented information about cosmic rays above 1018 eV. The first phase of the project, the construction and operation of a prototype system, known as the engineering array, has now been completed. It has allowed all of the sub-systems that will be used in the full instrument to be tested under field conditions. In this paper, the properties and performance of these sub-systems are described and their success illustrated with descriptions of some of the events recorded thus far.Auger Collaboration, ..., J. A. Bellido, ..., R. W. Clay, ..., B. R. Dawson, ..., G. J. Thornton, ..., N. R. Wild, et al.http://www.elsevier.com/wps/find/journaldescription.cws_home/505701/description#descriptio

Search for dark QCD with emerging jets in proton-proton collisions at sqrt{s} = 13 TeV

A search for ``emerging jets'' produced in proton-proton collisions at a center-of-mass energy of 13 TeV is performed using data collected by the CMS experiment corresponding to an integrated luminosity of 138 fb−1. This search examines a hypothetical dark quantum chromodynamics (QCD) sector that couples to the standard model (SM) through a scalar mediator. The scalar mediator decays into an SM quark and a dark sector quark. As the dark sector quark showers and hadronizes, it produces long-lived dark mesons that subsequently decay into SM particles, resulting in a jet, known as an emerging jet, with multiple displaced vertices. This search looks for pair production of the scalar mediator at the LHC, which yields events with two SM jets and two emerging jets at leading order. The results are interpreted using two dark sector models with different flavor structures, and exclude mediator masses up to 1950 (1950) GeV for an unflavored (flavor-aligned) dark QCD model. The unflavored results surpass a previous search for emerging jets by setting the most stringent mediator mass exclusion limits to date, while the flavor-aligned results provide the first direct mediator mass exclusion limits to date

Observation of the J/ψ→μ+μ-μ+μ- decay in proton-proton collisions at sqrt(s)=13 TeV

The J/ψ→μ+μ-μ+μ- decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 33.6 fb-1. Normalizing to the J/ψ→μ+μ- decay mode leads to a branching fraction of [10.1-2.7+3.3(stat)±0.4(syst)]×10-7, a value that is consistent with the standard model prediction