135 research outputs found
Roche lobe effects on the atmospheric loss of "Hot Jupiters"
Observational evidence of a hydrodynamically evaporating upper atmosphere of
HD209458b (Vidal-Madjar et al. 2003; 2004) and recent theoretical studies on
evaporation scenarios of ``Hot Jupiters'' in orbits around solar-like stars
with the age of the Sun indicate that the upper atmospheres of short-periodic
exoplanets experience hydrodynamic blow-off conditions resulting in loss rates
of the order of about 10^10 - 10^12 g s^-1 (Lammer et al. 2003; Yelle 2004;
Baraffe et al. 2004; Lecavlier des Etangs et al. 2004; Jaritz et al. 2005, Tian
et al. 2005; Penz et al. 2007). By studying the effect of the Roche lobe on the
atmospheric loss from short-periodic gas giants we found, that the effect of
the Roche lobe can enhance the hydrodynamic evaporation from HD209458b by about
2 and from OGLE-TR-56b by about 2.5 times. For similar exoplanets which are
closer to their host star than OGLE-TR-56b, the enhancement of the mass loss
can be even larger. Moreover, we show that the effect of the Roche lobe raises
the possibility that ``Hot Jupiters'' can reach blow-off conditions at
temperatures which are less than expected (< 10000 K) due to the stellar X-ray
and EUV (XUV) heating.Comment: 4 pages, 2 figures, submitted to A&
A review of composite product data interoperability and product life-cycle management challenges in the composites industry
A review of composite product data interoperability and product life-cycle management challenges is presented, which addresses “Product Life-cycle Management”, developments in materials. The urgent need for this is illustrated by the life-cycle management issues faced in modern military aircraft, where in-service failure of composite parts is a problem, not just in terms of engineering understanding, but also in terms of the process for managing and maintaining the fleet. A demonstration of the use of ISO 10303-235 for a range of through-life composite product data is reported. The standardization of the digital representation of data can help businesses to automate data processing. With the development of new materials, the requirements for data information models for materials properties are evolving, and standardization drives transparency, improves the efficiency of data analysis, and enhances data accuracy. Current developments in Information Technology, such as big data analytics methodologies, have the potential to be highly transformative
Galileo Probe Mass Spectrometer experiment
The Galileo Probe Mass Spectrometer (GPMS) is a Probe instrument designed to measure the chemical and isotopic composition including vertical variations of the constituents in the atmosphere of Jupiter. The measurement will be performed by in situ sampling of the ambient atmosphere in the pressure range from approximately 150 mbar to 20 bar. In addition batch sampling will be performed for noble gas composition measurement and isotopic ratio determination and for sensitivity enhancement of non-reactive trace gases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43775/1/11214_2004_Article_BF00216852.pd
Atmospheric Evolution
Earth's atmosphere has evolved as volatile species cycle between the
atmosphere, ocean, biomass and the solid Earth. The geochemical, biological and
astrophysical processes that control atmospheric evolution are reviewed from an
"Earth Systems" perspective, with a view not only to understanding the history
of Earth, but also to generalizing to other solar system planets and
exoplanets.Comment: 34 pages, 3 figures, 2 tables. Accepted as a chapter in
"Encyclopaedia of Geochemistry", Editor Bill White, Springer-Nature, 201
The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe
Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens probe, launched from the Cassini spacecraft, has made the first direct observations of the satellite's surface and lower atmosphere. Here we report direct atmospheric measurements from the Gas Chromatograph Mass Spectrometer (GCMS), including altitude profiles of the constituents, isotopic ratios and trace species ( including organic compounds). The primary constituents were confirmed to be nitrogen and methane. Noble gases other than argon were not detected. The argon includes primordial Ar-36, and the radiogenic isotope Ar-40, providing an important constraint on the outgassing history of Titan. Trace organic species, including cyanogen and ethane, were found in surface measurements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62703/1/nature04122.pd
KOSMOS and COSMOS: New facility instruments for the NOAO 4-meter telescopes
We describe the design, construction and measured performance of the Kitt
Peak Ohio State Multi-Object Spectrograph (KOSMOS) for the 4-m Mayall telescope
and the Cerro Tololo Ohio State Multi-Object Spectrograph (COSMOS) for the 4-m
Blanco telescope. These nearly identical imaging spectrographs are modified
versions of the OSMOS instrument; they provide a pair of new, high-efficiency
instruments to the NOAO user community. KOSMOS and COSMOS may be used for
imaging, long-slit, and multi-slit spectroscopy over a 100 square arcminute
field of view with a pixel scale of 0.29 arcseconds. Each contains two VPH
grisms that provide R~2500 with a one arcsecond slit and their wavelengths of
peak diffraction efficiency are approximately 510nm and 750nm. Both may also be
used with either a thin, blue-optimized CCD from e2v or a thick, fully
depleted, red-optimized CCD from LBNL. These instruments were developed in
response to the ReSTAR process. KOSMOS was commissioned in 2013B and COSMOS was
commissioned in 2014A.Comment: SPIE 2014 Astronomical Telescopes + Instrumentation, Proc. SPIE
9147-3
Upper atmospheres and ionospheres of planets and satellites
The upper atmospheres of the planets and their satellites are more directly
exposed to sunlight and solar wind particles than the surface or the deeper
atmospheric layers. At the altitudes where the associated energy is deposited,
the atmospheres may become ionized and are referred to as ionospheres. The
details of the photon and particle interactions with the upper atmosphere
depend strongly on whether the object has anintrinsic magnetic field that may
channel the precipitating particles into the atmosphere or drive the
atmospheric gas out to space. Important implications of these interactions
include atmospheric loss over diverse timescales, photochemistry and the
formation of aerosols, which affect the evolution, composition and remote
sensing of the planets (satellites). The upper atmosphere connects the planet
(satellite) bulk composition to the near-planet (-satellite) environment.
Understanding the relevant physics and chemistry provides insight to the past
and future conditions of these objects, which is critical for understanding
their evolution. This chapter introduces the basic concepts of upper
atmospheres and ionospheres in our solar system, and discusses aspects of their
neutral and ion composition, wind dynamics and energy budget. This knowledge is
key to putting in context the observations of upper atmospheres and haze on
exoplanets, and to devise a theory that explains exoplanet demographics.Comment: Invited Revie
First optical observation of the Moon’s sodium exosphere from the lunar orbiter SELENE (Kaguya)
Organic environments on Saturn’s moon, Titan: Simulating chemical reactions and analyzing products by FT-ICR and ion-trap mass spectrometry
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