A5048042559- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Space Exploration and Technology
- Spectroscopy and Laser Applications
- Isotope Analysis in Ecology
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Methane Hydrates and Related Phenomena
- Calibration and Measurement Techniques
- Solar and Space Plasma Dynamics
- Geology and Paleoclimatology Research
- Cloud Computing and Resource Management
- Geophysics and Gravity Measurements
- Molecular Spectroscopy and Structure
- Software-Defined Networks and 5G
- Spacecraft and Cryogenic Technologies
- Spaceflight effects on biology
- Atmospheric and Environmental Gas Dynamics
- Scientific Research and Discoveries
- Space Science and Extraterrestrial Life
- Space exploration and regulation
Carnegie Institution for Science
2021-2025
Naval University of Engineering
2024-2025
Earth and Planets Laboratory
2022-2024
Planetary Science Institute
2024
University of California, Santa Cruz
2020-2022
University of Amsterdam
2022
University of California, Berkeley
2014-2021
University of Nevada, Reno
2021
Ames Research Center
2017-2020
California Institute of Technology
2012-2018
Large-scale Internet applications, such as content distribution networks, are deployed across multiple datacenters and consume massive amounts of electricity. To provide uniformly low access latencies, these geographically distributed the deployment size at each location reflects regional demand for application. Consequently, an application's environmental impact can vary significantly depending on geographical end-users, electricity cost carbon footprint per watt is specific. In this paper,...
Results from the Kepler mission indicate that occurrence rate of small planets ($<3$ $R_\oplus$) in habitable zone nearby low-mass stars may be as high 80%. Despite this abundance, probing conditions and atmospheric properties on any habitable-zone planet is extremely difficult has remained elusive to date. Here, we report detection water vapor likely presence liquid icy clouds atmosphere $2.6$ $R_\oplus$ K2-18b. The simultaneous mid-atmosphere K2-18b particularly intriguing because receives...
We present the results of a precise near-infrared (NIR) radial velocity (RV) survey 32 low-mass stars with spectral types K2-M4 using CSHELL at NASA IRTF in $K$-band an isotopologue methane gas cell to achieve wavelength calibration and novel iterative RV extraction method. surveyed 14 members young ($\approx$ 25-150 Myr) moving groups, field star $\varepsilon$ Eridani as well 18 nearby ($<$ 25 pc) achieved typical single-measurement precisions 8-15 m s$^{-1}$ long-term stability 15-50...
Traditional datacenters are designed as a collection of servers, each which tightly couples the resources required for computing tasks. Recent industry trends suggest paradigm shift to disaggregated datacenter (DDC) architecture containing pool resources, built standalone resource blade and interconnected using network fabric.A key enabling (or blocking) factor disaggregation will be - support good application-level performance it becomes critical that fabric provide low latency...
Transmission spectroscopy1-3 of exoplanets has revealed signatures water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble Spitzer Space Telescopes were hindered by observations' relatively narrow wavelength range spectral resolving power, which precluded unambiguous identification other chemical species-in particular primary carbon-bearing molecules6,7. Here we report broad-wavelength 0.5-5.5 µm atmospheric...
Transmission spectroscopy provides insight into the atmospheric properties and consequently formation history, physics, chemistry of transiting exoplanets. However, obtaining precise inferences from transmission spectra requires simultaneously measuring strength shape multiple spectral absorption features a wide range chemical species. This has been challenging given precision wavelength coverage previous observatories. Here, we present spectrum Saturn-mass exoplanet WASP-39b obtained using...
Abstract Carbon dioxide (CO 2 ) is a key chemical species that found in wide range of planetary atmospheres. In the context exoplanets, CO an indicator metal enrichment (that is, elements heavier than helium, also called ‘metallicity’) 1–3 , and thus formation processes primary atmospheres hot gas giants 4–6 . It one most promising to detect secondary terrestrial exoplanets 7–9 Previous photometric measurements transiting planets with Spitzer Space Telescope have given hints presence but not...
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability. However, no unambiguous photochemical products have been detected in exoplanet to date. Recent observations from JWST Transiting Exoplanet Early Release Science Program found spectral absorption feature at 4.05 $\mu$m arising SO$_2$ atmosphere WASP-39b. WASP-39b 1.27-Jupiter-radii, Saturn-mass (0.28 M$_J$) gas giant orbiting Sun-like star with an equilibrium temperature...
Abstract Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining dominant chemical processes at work and, if equilibrium, revealing planet formation histories. Transmission spectroscopy (for example, refs. 1,2 ) provides necessary means by abundances of oxygen- carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution high precision, which, together, are not achievable with...
The recent inference of sulfur dioxide (SO2) in the atmosphere hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1-3 suggests that photochemistry is a key process high-temperature atmospheres4. This because low (<1 ppb) abundance SO2 under thermochemical equilibrium compared with produced H2O and H2S (1-10 ppm)4-9. However, was made single, small molecular feature transmission spectrum at 4.05 μm and, therefore, detection other absorption bands...
Abstract Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on nightside molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum hot Jupiter WASP-43b measured from 5 μm to 12 JWST’s Mid-Infrared Instrument. The spectra reveal large day–night temperature contrast (with...
The importance of minimizing flow completion times (FCT) in datacenters has led to a growing literature on new network transport designs. Of particular note is pFabric, protocol that achieves near-optimal FCTs. However, pFabric's performance comes at the cost generality, since pFabric requires specialized hardware embeds specific scheduling policy within fabric, making it hard meet diverse goals. Aiming for recent Fastpass proposal returns design based commodity and instead relies...
Large-scale Internet applications, such as content distribution networks, are deployed across multiple datacenters and consume massive amounts of electricity. To provide uniformly low access latencies, these geographically distributed the deployment size at each location reflects regional demand for application. Consequently, an application's environmental impact can vary significantly depending on geographical end-users, electricity cost carbon footprint per watt is specific. In this paper,...
Network middleboxes must offer high availability, with automatic failover when a device fails. Achieving availability is challenging because correctly restore lost state (e.g., activity logs, port mappings) but do so quickly in less than typical transport timeout values to minimize disruption applications) and little overhead failure-free operation additional per-packet latencies of 10-100s us). No existing middlebox design provides that correct, fast recover, imposes increased latency on...
We investigate the chemical stability of CO2-dominated atmospheres desiccated M dwarf terrestrial exoplanets using a one-dimensional photochemical model. Around Sun-like stars, CO2 photolysis by Far-UV (FUV) radiation is balanced recombination reactions that depend on water abundance. Planets orbiting stars experience more FUV radiation, and could be depleted in due to dwarfs' prolonged, high-luminosity pre-main sequences. show that, for water-depleted planets, catalytic cycle relying H2O2...
The James Webb Space Telescope (JWST) presents the opportunity to transform our understanding of planets and origins life by revealing atmospheric compositions, structures, dynamics transiting exoplanets in unprecedented detail. However, high-precision, timeseries observations required for such investigations have unique technical challenges, prior experience with Hubble, Spitzer, other facilities indicates that there will be a steep learning curve when JWST becomes operational. In this...
We quantify the amount of nitrogen oxides (NOx) produced through lightning and photochemical processes in Hadean atmosphere to be available ocean for emergence life. Atmospherically generated nitrate (NO3-) nitrite (NO2-) are most attractive high-potential electron acceptors pulling enabling crucial redox reactions autotrophic metabolic pathways at submarine alkaline hydrothermal vents. The atmosphere, dominated by CO2 N2, will produce nitric oxide (NO) when shocked lightning. Photochemical...
Heating, Ventilation, and Air Conditioning (HVAC) accounts for about half of the energy consumption in buildings. HVAC can be reduced by changing indoor air temperature setpoint, but setpoint too aggressively overly reduce user comfort. We have therefore designed implemented SPOT: a Smart Personalized Office Thermal control system that balances conservation with personal thermal comfort an office environment. SPOT relies on new model we call Predicted Personal Vote model. This quantitatively...
Abstract We present the first application of a bin-scheme microphysical and vertical transport model to determine size distribution titanium silicate cloud particles in atmospheres hot Jupiters. predict particle distributions from principles for grid planets at four representative equatorial longitudes, investigate how observed properties depend on atmospheric thermal structure mixing. The predicted are frequently bimodal irregular shape. There is negative correlation between total mass...
We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. obtained spectra and 100 $\mu$as precision astrometry both b c in two epochs, as well spatially resolving hot inner disk around star. Rejecting unstable orbits, we found a nonzero eccentricity for $0.17 \pm 0.06$, near-circular orbit c, an orbital configuration that is consistent planets migrating into 2:1 mean motion resonance. Enforcing dynamical stability, 95% upper...
We determine the observability in transmission of inhomogeneous cloud cover on limbs hot Jupiters through post processing a general circulation model to include distributions computed using microphysics model. find that both east and west limb often form clouds, but different properties these clouds enhances differences compared clear case. Using JWST it should be possible detect presence inhomogeneities by comparing shape transit lightcurve at multiple wavelengths because impart...
Abstract We present L ’-band imaging of the PDS 70 planetary system with Keck/NIRC2 using new infrared pyramid wave front sensor. detected both b and c in our images, as well rim circumstellar disk. After subtracting off a model disk, we measured astrometry photometry planets. Placing priors based on dynamics system, estimated to have semimajor axis <?CDATA ${20}_{-4}^{+3}$?> au ${34}_{-6}^{+12}$?> (95% credible interval). fit spectral energy distribution (SED) For b, were able place better...