The development of the Space Environment Viability of Organics (SEVO) experiment aboard the Organism/Organic Exposure to Orbital Stresses (O/OREOS) satellite     

Nathan E. Bramall  Richard Quinn  Andrew Mattioda  Kathryn Bryson  Julie D. Chittenden  Amanda Cook  Cindy Taylor  Giovanni Minelli  Pascale Ehrenfreund  Antonio J. Ricco  David Squires  Orlando Santos  Charles Friedericks  David Landis  Nykola C. Jones  Farid Salama  Louis J. Allamandola  Søren V. Hoffmann 《Planetary and Space Science》2012,60(1):121-130

The Space Environment Viability of Organics (SEVO) experiment is one of two scientific payloads aboard the triple-cube satellite Organism/ORganic Exposure to Orbital Stresses (O/OREOS). O/OREOS is the first technology demonstration mission of the NASA Astrobiology Small Payloads Program. The 1-kg, 1000-cm³ SEVO cube is investigating the chemical evolution of organic materials in interstellar space and planetary environments by exposing organic molecules under controlled conditions directly to the low-Earth orbit (LEO) particle and electromagnetic radiation environment. O/OREOS was launched on November 19, 2010 into a 650-km, 72°-inclination orbit and has a nominal operational lifetime of six months. Four classes of organic compounds, namely an amino acid, a quinone, a polycyclic aromatic hydrocarbon (PAH), and a metallo-porphyrin are being studied. Initial reaction conditions were established by hermetically sealing the thin-film organic samples in self-contained micro-environments. Chemical changes in the samples caused by direct exposure to LEO radiation and by interactions with the irradiated microenvironments are monitored in situ by ultraviolet/visible/near-infrared (UV/VIS/NIR) absorption spectroscopy using a novel compact fixed-grating CCD spectrometer with the Sun as its light source. The goals of the O/OREOS mission include: (1) demonstrating key small satellite technologies that can enable future low-cost astrobiology experiments, (2) deploying a miniature UV/VIS/NIR spectrometer suitable for in-situ astrobiology and other scientific investigations, (3) testing the capability to establish a variety of experimental reaction conditions to enable the study of astrobiological processes on small satellites, and (4) measuring the chemical evolution of organic molecules in LEO under conditions that can be extrapolated to interstellar and planetary environments. In this paper, the science and technology development of the SEVO instrument payload and its measurements are described.  相似文献   

Patterns of Surf Smelt, Hypomesus pretiosus, Intertidal Spawning Habitat Use in Puget Sound, Washington State     

Timothy Quinn  Kirk Krueger  Ken Pierce  Daniel Penttila  Kurt Perry  Tiffany Hicks  Dayv Lowry 《Estuaries and Coasts》2012,35(5):1214-1228

Surf smelt Hypomesus pretiosus are an important part of the Salish Sea food web and obligate beach spawners, yet little is known about the spatiotemporal distribution of spawning and beach characteristics related to spawning success. We counted smelt eggs at 51 sites around Camano Island, Puget Sound, Washington every 2?weeks for 1?year and at 13 of those 51 sites each month in the following year. At each site, we measured beach characteristics hypothesized to affect spawning habitat suitability as measured by egg abundance and mortality. Eggs were collected at 45 sites and pooled by month for analyses. Few sites (N?=?10, 19.6?%) contributed 87?% of total eggs and 89?% of all live eggs collected. Mean total egg counts at sites were higher (p?<?0.019) in Jul?CSep (1,790.7, SE?=?829.5) than in Jan?CMar (26.1, SE?=?10.2). Principal component and regression analyses suggested that aspect, fetch, solar radiation, and beach temperature predicted egg abundance but not mortality. Because a small proportion of sites appear to support most spawning activity, a conclusion consistent with year?2 egg counts, impacts to relatively few beaches could greatly affect surf smelt production.  相似文献   

The impact of mergers on relaxed X-ray clusters – I. Dynamical evolution and emergent transient structures     

Gregory B. Poole  Mark A. Fardal  Arif Babul  Ian G. McCarthy  Thomas Quinn  James Wadsley 《Monthly notices of the Royal Astronomical Society》2006,373(3):881-905

  相似文献   

Planetary nebula velocities in the disc and bulge of M31     

C. Halliday  D. Carter  T. J. Bridges  Z. C. Jackson  M. I. Wilkinson  D. P. Quinn  N. W. Evans  N. G. Douglas  H. R. Merrett  M. R. Merrifield  A. J. Romanowsky  K. Kuijken  M. J. Irwin 《Monthly notices of the Royal Astronomical Society》2006,369(1):97-119

We present radial velocities for a sample of 723 planetary nebulae in the disc and bulge of M31, measured using the WYFFOS fibre spectrograph on the William Herschel Telescope. Velocities are determined using the [O  iii ] λ5007 emission line. Rotation and velocity dispersion are measured to a radius of 50 arcmin (11.5 kpc), the first stellar rotation curve and velocity dispersion profile for M31 to such a radius. Our kinematics are consistent with rotational support at radii well beyond the bulge effective radius of 1.4 kpc, although our data beyond a radius of 5 kpc are limited. We present tentative evidence for kinematic substructure in the bulge of M31 to be studied fully in a later work. This paper is part of an ongoing project to constrain the total mass, mass distribution and velocity anisotropy of the disc, bulge and halo of M31.  相似文献   

Spectral comparison of heavily hydrated salts with disrupted terrains on Europa   总被引：1，自引：0，他引：1  

J.B. Dalton  O. Prieto-Ballesteros  C.S. Jamieson  R. Quinn 《Icarus》2005,177(2):472-490

Hydrated magnesium sulfate salts have been proposed as major components of the disrupted, reddish terrains on the surface of Europa. This is based on near-infrared reflectance spectra which contain distorted and asymmetric water absorption features typical of moderately hydrated materials such as hexahydrite (MgSO₄⋅6H₂O) and epsomite (MgSO₄⋅7H₂O). Hydrated magnesium sulfates having many waters of hydration could produce improved spectral matches. Here we present cryogenic laboratory spectra of highly hydrated sulfur-bearing salts, including hexahydrite, epsomite, bloedite (Na₂Mg(SO₄)₂⋅4H₂O), mirabilite (Na₂SO₄⋅10H₂O), sodium sulfide nonahydrate (Na₂S⋅9H₂O), supersaturated MgSO₄, NaHCO₃, and Na₂SO₄ brines, and magnesium sulfate dodecahydrate (MgSO₄⋅12H₂O). All have been measured under conditions of pressure and temperature appropriate to the surface environment of Europa. Novel methods for preparation, verification and analysis of MgSO₄⋅12H₂O, which is not stable at standard temperature and pressure (STP), are described. At 100 K, all of these materials exhibit distorted and asymmetric absorption features similar to those in the Europa observations, as well as several weaker, narrow absorptions having widths ranging from 15 to 80 nm. While the agreement with Galileo NIMS observations of dark terrains on Europa is indeed better for highly hydrated salts than for salts of lower hydration states, we conclude that none of these materials alone can account for all of the observed spectral character. As previously suggested, Europa's reddish material appears to be a complex mixture of sulfate hydrates and other materials.  相似文献   

The inner structure of ΛCDM haloes – III. Universality and asymptotic slopes     

J. F. Navarro †  E. Hayashi  C. Power  A. R. Jenkins  C. S. Frenk  S. D. M. White  V. Springel  J. Stadel  T. R. Quinn 《Monthly notices of the Royal Astronomical Society》2004,349(3):1039-1051

  相似文献   

Evolution of the density profiles of dark matter haloes     

Darren Reed  Fabio Governato  Licia Verde  Jeffrey Gardner  Thomas Quinn  Joachim Stadel  David Merritt  George Lake 《Monthly notices of the Royal Astronomical Society》2005,357(1):82-96

  相似文献   

A geovisual analytics exploration of the OpenStreetMap crowd     

Sterling D. Quinn  Alan M. MacEachren 《制图学和地理信息科学》2018,45(2):140-155

It is sometimes easy to forget that massive crowdsourced data products such as Wikipedia and OpenStreetMap (OSM) are the sum of individual human efforts stemming from a variety of personal and institutional interests. We present a geovisual analytics tool called Crowd Lens for OpenStreetMap designed to help professional users of OSM make sense of the characteristics of the “crowd” that constructed OSM in specific places. The tool uses small multiple maps to visualize each contributor’s piece of the crowdsourced whole, and links OSM features with the free-form commit messages supplied by their contributors. Crowd Lens allows sorting and filtering contributors by characteristics such as number of contributions, most common language used, and OSM attribute tags applied. We describe the development and evaluation of Crowd Lens, showing how a multiple-stage user-centered design process (including testing by geospatial technology professionals) helped shape the tool’s interface and capabilities. We also present a case study using Crowd Lens to examine cities in six continents. Our findings should assist institutions deliberating OSM’s fitness for use for different applications. Crowd Lens is also potentially informative for researchers studying Internet participation divides and ways that crowdsourced products can be better comprehended with visual analytics methods.  相似文献   

Evidence of multidecadal climate variability and the Atlantic Multidecadal Oscillation from a Gulf of Mexico sea-surface temperature-proxy record   总被引：1，自引：1，他引：0  

Richard Z. Poore  Kristine L. DeLong  Julie N. Richey  Terrence M. Quinn 《Geo-Marine Letters》2009,29(6):477-484

A comparison of a Mg/Ca-based sea-surface temperature (SST)-anomaly record from the northern Gulf of Mexico, a calculated index of variability in observed North Atlantic SST known as the Atlantic Multidecadal Oscillation (AMO), and a tree-ring reconstruction of the AMO contain similar patterns of variation over the last 110 years. Thus, the multidecadal variability observed in the instrumental record is present in the tree-ring and Mg/Ca proxy data. Frequency analysis of the Gulf of Mexico SST record and the tree-ring AMO reconstruction from 1550 to 1990 found similar multidecadal-scale periodicities (~30–60 years). This multidecadal periodicity is about half the observed (60–80 years) variability identified in the AMO for the 20th century. The historical records of hurricane landfalls reveal increased landfalls in the Gulf Coast region during time intervals when the AMO index is positive (warmer SST), and decreased landfalls when the AMO index is negative (cooler SST). Thus, we conclude that alternating intervals of high and low hurricane landfall occurrences may continue on multidecadal timescales along the northern Gulf Coast. However, given the short length of the instrumental record, the actual frequency and stability of the AMO are uncertain, and additional AMO proxy records are needed to establish the character of multidecadal-scale SST variability in the North Atlantic.  相似文献   

Eclipsing binaries in the MOST satellite fields     

T. Pribulla  S.M. Rucinski  D.W. Latham  S.N. Quinn  M. Siwak  J.M. Matthews  R. Kuschnig  J.F. Rowe  D.B. Guenther  A.F.J. Moffat  D. Sasselov  G.A.H. Walker  W.W. Weiss 《Astronomische Nachrichten》2010,331(4):397-411

Sixteen new eclipsing binaries have been discovered by the MOST satellite among guide stars used to point its telescope in various fields. Several previously known eclipsing binaries were also observed by MOST with unprecedented quality. Among the objects we discuss in more detail are short‐period eclipsing binaries with eccentric orbits in young open clusters: V578 Mon in NGC 2244 and HD 47934 in NGC 2264. Long nearly‐continuous photometric runs made it possible to discover three long‐period eclipsing binaries with orbits seen almost edge‐on: HD 45972 with P = 28.1 days and two systems (GSC 154 1247 and GSC 2141 526) with P > 25 days. The high precision of the satellite data led to discoveries of binaries with very shallow eclipses (e.g., HD 46180 with A = 0.016 mag, and HD 47934 with A = 0.025 mag). Ground‐based spectroscopy to support the space‐based photometry was used to refine the models of several of the systems (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献