A5062339384- Astro and Planetary Science
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Ionosphere and magnetosphere dynamics
- Space Exploration and Technology
- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Astrophysics and Star Formation Studies
- Geophysics and Gravity Measurements
- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Laser-induced spectroscopy and plasma
- Scientific Research and Discoveries
- Nuclear physics research studies
- Spacecraft and Cryogenic Technologies
- Cardiac tumors and thrombi
- Space Satellite Systems and Control
- Cardiovascular and Diving-Related Complications
- Pulsars and Gravitational Waves Research
- High Altitude and Hypoxia
- Environmental, Ecological, and Cultural Studies
- Earth Systems and Cosmic Evolution
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
Northumbria University
2022-2025
Boston University
2024
University of Leicester
2014-2023
University College London
2000-2014
University of Hawaii System
1999-2010
Google (United States)
2006
European Southern Observatory
2005
University of Maryland, College Park
2005
University of Liège
2005
Pomona College
2005
Abstract Juno's highly eccentric polar orbit takes it to perijove distances of 1.06 on each orbit. For the first perijove, this occurred just north jovigraphic equator, but has precessed by about a degree per over mission. Minimum altitudes vary from 3,200–8,000 km through The Waves instrument observes number plasma wave modes in and near non‐auroral ionosphere that provide information local electron density, including oscillations occur at frequency whistler‐mode hiss which an upper limit...
While the terrestrial aurorae are known to be driven primarily by interaction of Earth's magnetosphere with solar wind, there is considerable evidence that auroral emissions on Jupiter and Saturn internal processes, main energy source being planets' rapid rotation. Prior observations have suggested might some influence wind Jupiter's indicated storms can occur at times pressure increases. To investigate in detail dependence processes conditions, a large campaign these planets has been...
Contrary to the case of Earth, main auroral oval on Jupiter is related breakdown plasma corotation in middle magnetosphere. Even if root causes for emissions are Io's volcanism and Jupiter's fast rotation, changes aurora could be attributed either these internal factors or fluctuations solar wind. Here we show multiple lines evidence from a major internally‐controlled magnetospheric reconfiguration that took place Spring 2007. Hubble Space Telescope far‐UV images continuously expanded over...
Prompted by recent observations of ion flows from Doppler measurements infrared auroras, we here discuss the nature plasma flow in Jupiter's high‐latitude ionosphere. The physical picture is based on a combination three elements, namely an inner Hill‐type sub‐corotating region containing outward‐diffusing iogenic plasma, outer where lost down tail, principally dusk and midnight sector via reconnection‐related Vasyliunas‐cycle, finally outermost boundary located dawn‐side magnetosphere which...
From the 27th to 28th January 2009, Cassini spacecraft remotely acquired combined observations of Saturns southern aurorae at radio, ultraviolet and infrared wavelengths, while monitoring ion injections in middle magnetosphere from energetic neutral atoms. Simultaneous measurements included sampling a full planetary rotation, relevant timescale investigate auroral emissions driven by processes internal magnetosphere. In addition, this interval coincidently matched powerful substorm-like...
We present the first comparison of Jupiter's auroral morphology with an extended, continuous, and complete set near‐Jupiter interplanetary data, revealing response auroras to conditions. show that for ∼1–3 days following compression region onset, planet's main emission brightened. A duskside poleward also brightened during compressions, as well shallow rarefaction conditions at start program. The power emitted from noon active did not exhibit dependence on any parameter, though typically...
${\text{H}}_{3}^{+}$, the simplest polyatomic molecular ion, has been discovered to play an extensive role in physics and chemistry of astrophysical environments such as interstellar clouds atmosphere giant planets our Solar System beyond. This review presents account progress achieved this realm after three decades planetary observations, starting from its first, unexpected identification Jupiter's up most recent data returned by...
Spectroscopic studies of the upper atmospheres giant planets using infrared wavelengths sensitive to H3+ molecular ion show that this species plays a critical role in determining physical conditions there. For Jupiter, we propose recently detected electrojet holds key mechanism by which equatorial plasma sheet is kept (partial) co–rotation with planet, and also provides previously unconsidered source energy helps explain why jovian thermosphere considerably hotter than expected. Saturn,...
We review the role of H3+ in planetary atmospheres, with a particular emphasis on its effect cooling and stabilising, an that has been termed "H3+ thermostat" (see Miller et al., Philos. Trans. R. Soc. London, Ser. A, 2000, 58, 2485). In course our analysis this effect, we found functions make use partition function, Q(T) based calculated energy levels Neale Tennyson (Astrophys. J., 1995, 454, L169) may underestimate just how much ion is radiating to space. So present new fit values accurate...
This study is based on multi‐planet multi‐wavelength observations of planetary aurorae throughout the heliosphere, acquired along propagation path a series consecutive interplanetary shocks. The underlying motivation to track shocks was increase probability detection auroral emissions at Uranus. Despite several Earth‐based attempts in past few years, Far‐UV (FUV) and Near‐IR (NIR) wavelengths, such have never been unambiguously re‐observed since their discovery by Voyager 2 1986. Here, we...
Abstract Jupiter’s upper atmosphere is considerably hotter than expected from the amount of sunlight that it receives 1–3 . Processes couple magnetosphere to give rise intense auroral emissions and enormous deposition energy in magnetic polar regions, so has been presumed redistribution this could heat rest planet 4–6 Instead, most thermospheric global circulation models demonstrate trapped at high latitudes by strong winds on rapidly rotating 3,5,7–10 Consequently, other possible sources...
Abstract Jupiter’s upper atmosphere is composed of a neutral thermosphere and charged ionosphere. In the latter, dominant molecular ion H 3 + emits in near-infrared, allowing for remote exploration physical properties atmosphere. However, Jovian low-latitude ionosphere remains largely unexplored because emissions from this region are faint spectrally entangled with bright species, such as CH 4 . Here, we present James Webb Space Telescope observations Great Red Spot, showing unexpected...
Recent analysis of high‐resolution spectra Doppler‐shifted H 3 + emission from the auroral/polar regions Jupiter revealed a complex wind system, with persistent auroral electrojet and strong anti‐sunward flows in region lesser intensity centred around magnetic pole [ Stallard et al. , 2001 ]. This region, which we have called Dark Polar Region (DPR), is re‐investigated, transforming observed line‐of‐sight velocities into frame reference fixed respect to pole. The DPR shown include...
We present Cassini Visual and Infrared Mapping Spectrometer observations of infrared auroral emissions from the noon sector Saturn's ionosphere revealing multiple intense arcs separated by dark regions poleward main oval. The are interpreted as ionospheric signatures bursts reconnection occurring at dayside magnetopause. were associated with upward field‐aligned currents, magnetic which detected high planetary latitudes. Magnetic field particle in adjacent downward current showed 100–360 keV...
We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts emission at poleward boundary a solar wind-induced storm, propagating ∼330% rigid corotation from near ∼01 h LT toward ∼08 LT. suggest that these are indicative ongoing, bursty reconnection lobe flux magnetotail, providing strong evidence Saturn's caused by large-scale closure. also later evolution similar storm...
Abstract Jupiter's South Polar Region (SPR) was observed by James Webb Space Telescope/Mid‐Infrared Instrument in December 2022. We used the Medium Resolution Spectrometer mode to provide new information about stratosphere. The southern auroral region visible and influenced atmosphere several ways: (a) In interior of oval, we retrieved peak temperatures at two distinct pressure levels near 0.01 1 mbar, with warmer respect non‐auroral regions 12 ± 2 K 37 4 respectively. A cold polar vortex is...
The incredible sensitivity of the James Webb Space Telescope has enable completely new views faint H3+ ionospheric emission from giant planets, revealing features that were not visible existing observing facilities. At Jupiter, above Great Red Spot, an intricate pattern was observed in ionosphere using NIRSpec IFU (Early Release Science programme #1373), with bright and dark bands, arcs, spots. This surprising, since low-latitude previously rendered relatively bland by modelling. We suggest...
Ground-based telescope observations of H3+ are critical because they currently the only way to remotely measure ionospheric flows at giant planets. These Jupiter for supporting space missions, such as Juno, IR instruments, JIRAM, lack spectral resolution Doppler shift spectra, from which line-of-sight velocity can be derived and inferred. Furthermore, spacecraft provide information along orbital path swathes aurora, however, ground-based a global view aurora.Past studies, using spectroscopic...
Abstract To date, no investigation has documented ionospheric flows at Uranus. Previous investigations of Jupiter and Saturn have demonstrated that mapping ion winds can be used to understand currents how these connect magnetosphere‐ionosphere coupling. We present a study Uranus's near infrared emissions (NIR) using data from the Keck II Telescope's Near InfraRed SPECtrograph (NIRSPEC) Telescope Facility's iSHELL spectrograph. H 3 + emission lines were derive dawn‐to‐dusk intensity,...
Abstract Jupiter's polar aurorae deliver significant heating at the poles, thought to spread across planet through atmospheric winds. Additionally, ground‐based Keck observations have revealed a large‐scale high‐temperature region, spatially distinct from aurorae. Here, we investigate origins and characteristics of feature using data, in‐situ Juno spacecraft measurements, solar wind modeling. exited magnetosphere on approach Jupiter, coinciding with modeled high‐speed impact that compressed...