22 research outputs found

    Overview of HST observa7ons of Jupiter’s ultraviolet aurora during Juno orbits 3 to 7

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    Jupiter’s permanent ultraviolet auroral emissions have been systematically monitored from Earth orbit with the Hubble Space Telescope (HST) during an 8-month period. The Girst part of this HST large program (GO-14634) was meant to support the NASA Juno prime mission during orbits PJ03 through PJ07. The HST program will resume in Feb 2018, in time for Juno’s PJ11 perijove, right after HST’s solar and lunar avoidance periods. HST observations are designed to provide a Jovian auroral activity background for all instruments on-board Juno and for the numerous ground based and space based observatories participating to the Juno mission. In particular, several HST visits were programmed in order to obtain as many simultaneous observations with Juno-UVS as possible, sometimes in the same hemisphere, sometimes in the opposite one. In addition, the timing of some HST visits was set to take advantage of Juno’s multiple crossings of the current sheet and of the magnetic Gield lines threading the auroral emissions. These observations are obtained with the Space Telescope Imaging Spectrograph (STIS) in time-tag mode, they consist in spatially resolved movies of Jupiter’s highly dynamic aurora with timescales ranging from seconds to several days. Here, we present an overview of the present -numerous- HST results. They demonstrate that while Jupiter is always showing the same basic auroral components, it is also displaying an ever-changing auroral landscape. The complexity of the auroral morphology is such that no two observations are alike. Still, in this apparent chaos some patterns emerge. This information is giving clues on magnetospheric processes at play at the local and global scales, the latter being only accessible to remote sensing instruments such as HST

    Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

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    A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk

    Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

    Get PDF
    A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P = 9.2 x 10(-20)), ER-negative BC (P = 1.1 x 10(-13)), BRCA1-associated BC (P = 7.7 x 10(-16)) and triple negative BC (P-diff = 2 x 10(-5)). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P = 2 x 10(-3)) and ABHD8 (PPeer reviewe

    Evolution of the auroral signatures of Jupiter’s magnetospheric injections

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    We report on the longitudinal and azimuthal motions of auroral signatures of Jupiter’s magnetospheric injections appearing in Hubble Space Telescope (HST) images in the northern and southern hemispheres. Based on HST spectral observations of time-tag mode and numerical simulations, we estimate the age of auroral signatures of plasma injections

    Ultraviolet auroral emissions on giant planets

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    The aurorae on Jupiter and Saturn are the most powerful proper ultraviolet emissions in our solar system, after the Sun’s. They can only be observed outside the absorbing atmosphere of the Earth with space telescopes such as the Hubble Space Telescope or the Hisaki Telescope, or from Spacecraft orbiting these planets, like Cassini for Saturn and Juno for Jupiter. We will review the types of observation that can be obtained with these different instruments and how this information can be used to interpret the auroral emissions

    Isolated transient UV auroral structures at Jupiter: possible signatures of magnetospheric injections 

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    We investigate transient ultraviolet auroral features located equatorward of the main emission (130 features) based on Hubble Space Telescope (HST) observations of the northern and southern Jovian hemispheres (2000-2007). Several properties of the auroral emissions are analyzed, such as their position in auroral region, power and brightness. Additionally, we magnetically map the auroral structures to the equatorial plane using VIPAL model and we compare their observed properties with those of magnetospheric injections observed by Galileo. We suggest that these transient auroral structures could be related to magnetospheric injections. The mapped radial position and system III longitude of the observed auroral features are in good agreement with those of the injections observed in the equatorial plane by Galileo. Based on power and brightness of the auroral features, we discuss the mechanisms involved in the ionosphere-magnetosphere coupling injections. This comparative study demonstrates that the structures under study are related to magnetospheric injections and sheds light to the mechanism involved in the magnetosphere-ionosphere dynamics

    Jupiter's equatorward auroral features: possible signatures of magnetospheric injections

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    The present study investigates the characteristics of ultraviolet auroral features located equatorward of the main emission appearing in Hubble Space Telescope images of the northern and southern Jovian hemispheres obtained in 2000-2007. On average, one feature is observed every day, but several auroral structures are occasionally seen over a wide range of local times in the same image. Several properties of these features are analyzed, such as their location, emitted power and lifetime. Additionally, we magnetically map the auroral features to the equatorial plane using the VIPAL model in order to compare their observed properties with those of magnetospheric injections detected by the Galileo spacecraft. The equatorward auroral features show up between the Io footpath and the main auroral emission, at all System III longitudes, in agreement with Galileo measurements. Moreover, we compare the magnetic flux associated with these features with estimates of the out-going flux related to the radial transport of plasma in the Jovian magnetosphere and we find that they could account for at least one third of this flux. This comparative study shows that the auroral features under study are most probably related to magnetospheric injections and thus sheds light on the processes involved in the magnetosphere-ionosphere dynamics
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