ExoOrg_NAI
... classes of comets, based on their organic chemistry, and to tie each class to a place of origin in the protoplanetary disk. We propose to evaluate the size distribution of icy planetesimals scattered towards Earth, and to assess the delivery of organics from each giant-planets’ zone. Organics contai ...
... classes of comets, based on their organic chemistry, and to tie each class to a place of origin in the protoplanetary disk. We propose to evaluate the size distribution of icy planetesimals scattered towards Earth, and to assess the delivery of organics from each giant-planets’ zone. Organics contai ...
Composition and Evolution of Interstellar Clouds
... HIM and WIM, i.e., the shocks and pressures from ionized gas, can sweep up and compress WNM or shear apart CNM diffuse clouds. Hence, primarily supernovae, and to a lesser extent stellar winds, are responsible for the turbulent nature of the ISM, the multiple components of the ISM, and the structure ...
... HIM and WIM, i.e., the shocks and pressures from ionized gas, can sweep up and compress WNM or shear apart CNM diffuse clouds. Hence, primarily supernovae, and to a lesser extent stellar winds, are responsible for the turbulent nature of the ISM, the multiple components of the ISM, and the structure ...
Observations, Modeling and Theory of Debris Disks
... Universidad Autónoma de Madrid Main sequence stars, like the Sun, are often found to be orbited by circumstellar material that can be categorized into two groups, planets and debris. The latter is made up of asteroids and comets, as well as the dust and gas derived from them, which makes debris dis ...
... Universidad Autónoma de Madrid Main sequence stars, like the Sun, are often found to be orbited by circumstellar material that can be categorized into two groups, planets and debris. The latter is made up of asteroids and comets, as well as the dust and gas derived from them, which makes debris dis ...
Abstracts - Physics of Evolved Stars 2015
... intermediate main-sequence mass (5-8 solar masses) stars before they evolve into the post-AGB and planetary-nebula stages. AGB stars lose most of their stellar envelope in the form of a gaseous and dusty stellar wind. This wind eventually grows to such high mass-loss rates that the central star beco ...
... intermediate main-sequence mass (5-8 solar masses) stars before they evolve into the post-AGB and planetary-nebula stages. AGB stars lose most of their stellar envelope in the form of a gaseous and dusty stellar wind. This wind eventually grows to such high mass-loss rates that the central star beco ...
Nebulae.The Lagoon and Dumbbell Nebulae
... M42 – The Orion Nebula: photography ......................................................................................................... 12 Conclusion ................................................................................................................................................ ...
... M42 – The Orion Nebula: photography ......................................................................................................... 12 Conclusion ................................................................................................................................................ ...
Observations, Modeling and Theory of Debris Disks
... Universidad Autónoma de Madrid Main sequence stars, like the Sun, are often found to be orbited by circumstellar material that can be categorized into two groups, planets and debris. The latter is made up of asteroids and comets, as well as the dust and gas derived from them, which makes debris dis ...
... Universidad Autónoma de Madrid Main sequence stars, like the Sun, are often found to be orbited by circumstellar material that can be categorized into two groups, planets and debris. The latter is made up of asteroids and comets, as well as the dust and gas derived from them, which makes debris dis ...
SPATIAL STUDY WITH THE VERY LARGE TELESCOPE OF A NEW
... (VLT) under 0>4 seeing conditions, which unveil a dark dust lane oriented east-west between two characteristic northern and southern reflection nebulae. This new circumstellar dust disk has a radius of 2>15 (300 AU at 140 pc) and a width of 1>2 (170 AU at 140 pc). Thanks to its location at the periph ...
... (VLT) under 0>4 seeing conditions, which unveil a dark dust lane oriented east-west between two characteristic northern and southern reflection nebulae. This new circumstellar dust disk has a radius of 2>15 (300 AU at 140 pc) and a width of 1>2 (170 AU at 140 pc). Thanks to its location at the periph ...
The dust temperatures of the pre-stellar cores in the ρ Oph main
... Each clump is surrounded by a virtual ambient cloud, which has a uniform density. The role of these ambient clouds is to modify the ambient radiation field that heats each clump externally. The optical extinction through the ambient cloud is chosen so that the peak of computed SED of each clump corr ...
... Each clump is surrounded by a virtual ambient cloud, which has a uniform density. The role of these ambient clouds is to modify the ambient radiation field that heats each clump externally. The optical extinction through the ambient cloud is chosen so that the peak of computed SED of each clump corr ...
25June2004 - Division of Geological and Planetary Sciences
... In older systems, CO disk emission is common: Herbig Ae stars, from ~face-on (AB Aur) to highly inclined (HD 163296). CO lines correlated with inclination and much narrower than those of H I Disk! ...
... In older systems, CO disk emission is common: Herbig Ae stars, from ~face-on (AB Aur) to highly inclined (HD 163296). CO lines correlated with inclination and much narrower than those of H I Disk! ...
GALEX and Star Formation
... Why is UV data sensitive to star formation? Young massive stars, hot, luminous, and short-lived, are the unambiguous tracers of star formation. They are luminous enough that they can be seen in distant galaxies. They evolve on fast timescales (.10 Myrs for Otype stars), therefore they also trace the ...
... Why is UV data sensitive to star formation? Young massive stars, hot, luminous, and short-lived, are the unambiguous tracers of star formation. They are luminous enough that they can be seen in distant galaxies. They evolve on fast timescales (.10 Myrs for Otype stars), therefore they also trace the ...
Astrochemistry and Star Formation
... those that include the dust particles in some active manner (Herbst 2005a). Dust particles are important to chemistry for a variety of reasons; most crucially they provide a surface on which chemical reactions can occur. Taking account of this surface chemistry is extraordinarily difficult, however, ...
... those that include the dust particles in some active manner (Herbst 2005a). Dust particles are important to chemistry for a variety of reasons; most crucially they provide a surface on which chemical reactions can occur. Taking account of this surface chemistry is extraordinarily difficult, however, ...
Physical Properties of the Gas and Dust in the Orion B Molecular
... distinguish these units from the clumps described above, we call them dense “cores” (see Table 1). These cloud cores are, however, not the progenitors of individual stars. Their masses are, in general, much higher than the masses of the stars they form and their mass spectrum (LBS; Tatematsu et al. ...
... distinguish these units from the clumps described above, we call them dense “cores” (see Table 1). These cloud cores are, however, not the progenitors of individual stars. Their masses are, in general, much higher than the masses of the stars they form and their mass spectrum (LBS; Tatematsu et al. ...
PDF only - at www.arxiv.org.
... 1972 (Hartogh et al. 2010). While the column density is (within the error bars) compatible with the 1972 observations and shows only small deviations to recent ground-based in situ measurements of Curiosity, HIFI derived deviations from the constant vertical altitude profile not predict ...
... 1972 (Hartogh et al. 2010). While the column density is (within the error bars) compatible with the 1972 observations and shows only small deviations to recent ground-based in situ measurements of Curiosity, HIFI derived deviations from the constant vertical altitude profile not predict ...
The Galactic Environment of the Sun
... moves with a speed of about 16.5 kilometers per second, or nearly 50 lightyears per million years. The sun’s path is inclined about 25 degrees to the plane of the galaxy and is headed toward a region in the constellation of Hercules near its border with Lyra. The sun oscillates through the plane of ...
... moves with a speed of about 16.5 kilometers per second, or nearly 50 lightyears per million years. The sun’s path is inclined about 25 degrees to the plane of the galaxy and is headed toward a region in the constellation of Hercules near its border with Lyra. The sun oscillates through the plane of ...
Jon Abbatt - Earth, Atmospheric, and Planetary Physics
... To some degree, this depends on the setting. For example, in a large dust storm coming off the Gobi desert, the total particle surface area and mass will be overwhelmingly dominated by mineral dust. But, as this mineral dust “ages”, it will pick up a thin mixed sulfate/organic coating in addition to ...
... To some degree, this depends on the setting. For example, in a large dust storm coming off the Gobi desert, the total particle surface area and mass will be overwhelmingly dominated by mineral dust. But, as this mineral dust “ages”, it will pick up a thin mixed sulfate/organic coating in addition to ...
Photoprocesses in protoplanetary disks
... CH2+. Accurate CI calculations by Theodorakopoulos & Petsalakis69 show many dipole-allowed excited states below 13.6 eV. Their 1, 2 and 3 2B2, 2, 3 and 4 2A1 and 2 2B1 states have been included with f = 0.008, 0.0001, 0.02, 0.01, 0.06, 0.05 and 0.03, respectively. CH4+. Detailed studies of the CH4+ ...
... CH2+. Accurate CI calculations by Theodorakopoulos & Petsalakis69 show many dipole-allowed excited states below 13.6 eV. Their 1, 2 and 3 2B2, 2, 3 and 4 2A1 and 2 2B1 states have been included with f = 0.008, 0.0001, 0.02, 0.01, 0.06, 0.05 and 0.03, respectively. CH4+. Detailed studies of the CH4+ ...
Seminar Outburst of Comet 17P/Holmes
... velocity of expanding dust coma was obtained vc = 0.57 ± 0.02 km s−1 . This is consistent with photographically obtained radial velocity [16]. ...
... velocity of expanding dust coma was obtained vc = 0.57 ± 0.02 km s−1 . This is consistent with photographically obtained radial velocity [16]. ...
Nucleosynthesis and Chemical Evolution of Oxygen
... NASA Johnson Space Center Houston, TX 77058 Abstract. Of the elements strictly synthesized in stars, oxygen is by far the most abundantly produced. We review the nucleosynthesis and Galactic chemical evolution of this important element. We then review its isotopic composition in presolar grains reco ...
... NASA Johnson Space Center Houston, TX 77058 Abstract. Of the elements strictly synthesized in stars, oxygen is by far the most abundantly produced. We review the nucleosynthesis and Galactic chemical evolution of this important element. We then review its isotopic composition in presolar grains reco ...
The mass-loss return from evolved stars to the Large Magellanic Cloud
... fix the outer radius at 1000 Rin . Based on the results from our previous study, we use amorphous carbon dust mixed with 10% silicon carbide by mass. The grain size distribution follows a power-law and an exponential falloff at large sizes. The models span twenty-six values of 11.3 μm optical depth, ...
... fix the outer radius at 1000 Rin . Based on the results from our previous study, we use amorphous carbon dust mixed with 10% silicon carbide by mass. The grain size distribution follows a power-law and an exponential falloff at large sizes. The models span twenty-six values of 11.3 μm optical depth, ...
Injection mechanisms of short-lived radionuclides and their
... plasma source mass spectrometry, and the need for improved inter-laboratory calibrations. Two recent reports (Bizzarro et al., 2007; Quitté and Markowski, 2007), however, did not find the expected excess 60Ni in SAH99555, a basaltic angrite with a well-constrained Pb–Pb age of 4564.55 ± 0.16 Myr (Co ...
... plasma source mass spectrometry, and the need for improved inter-laboratory calibrations. Two recent reports (Bizzarro et al., 2007; Quitté and Markowski, 2007), however, did not find the expected excess 60Ni in SAH99555, a basaltic angrite with a well-constrained Pb–Pb age of 4564.55 ± 0.16 Myr (Co ...
Astrophysical and astrochemical insights into the origin of life
... The clouds, which are thought to occupy only a minor volume fraction of the overall ISM, are in turn divisible into the so-called diffuse clouds which are characterized by visual extinctions Av ∼ 1 mag, densities of the order of 100 atoms cm−3 , and temperatures ∼100 K; dense clouds with Av > 5 mag, ...
... The clouds, which are thought to occupy only a minor volume fraction of the overall ISM, are in turn divisible into the so-called diffuse clouds which are characterized by visual extinctions Av ∼ 1 mag, densities of the order of 100 atoms cm−3 , and temperatures ∼100 K; dense clouds with Av > 5 mag, ...
Galactic Nebulae
... Planetary Nebulae(medium- low mass stars) Layers of gas expelled from star at end of star`s life Core of star – hot/ bright – uv radiation ionizes ejected layers Ejected layers – radiate at visible wavelengths Planetary nebulae – return elements to interstellar medium ...
... Planetary Nebulae(medium- low mass stars) Layers of gas expelled from star at end of star`s life Core of star – hot/ bright – uv radiation ionizes ejected layers Ejected layers – radiate at visible wavelengths Planetary nebulae – return elements to interstellar medium ...
The prebiotic molecules observed in the interstellar gas
... intensity of the molecular radio emission lines in space depends mainly on two factors, both of which can be well determined: the molecular electric dipole moment and the rotational partition function, which depends on the populations of the various levels. For stable molecules, the dipole moment ca ...
... intensity of the molecular radio emission lines in space depends mainly on two factors, both of which can be well determined: the molecular electric dipole moment and the rotational partition function, which depends on the populations of the various levels. For stable molecules, the dipole moment ca ...
astro-ph/0303282 PDF
... V=3.7 star, producing good AO correction (Strehl ~ 0.4 at 2.1 µm). Although NIRC2 has a focalplane coronagraph and selectable Lyot pupil stops, these modes had not been fully commissioned and we did not use them for these observations. At each position we obtained 15 K’ (2.1 µm) images in a 5-posit ...
... V=3.7 star, producing good AO correction (Strehl ~ 0.4 at 2.1 µm). Although NIRC2 has a focalplane coronagraph and selectable Lyot pupil stops, these modes had not been fully commissioned and we did not use them for these observations. At each position we obtained 15 K’ (2.1 µm) images in a 5-posit ...
Cosmic dust
Cosmic dust is dust which exists in space. It is for the most part a type of small dust particles which are a few molecules to 0.1 µm in size. A smaller fraction of all dust in space consists of larger refractory minerals that condensed as matter left the stars. It is called ""stardust"" and is included in a separate section below. The dust density in the local interstellar medium of the Local Bubble is approximately 10−6 × dust grain/m3 with each grain having a mass of approximately 10−17 kg.Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust (such as in the zodiacal cloud) and circumplanetary dust (such as in a planetary ring). In the Solar System, interplanetary dust causes the zodiacal light. Sources of Solar System dust include comet dust, asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through the Solar System. The terminology has no specific application for describing materials found on the planet Earth except for dust that has demonstrably fallen to Earth. By one estimate, as much as 40,000 tons of cosmic dust reaches the Earth's surface every year. In October 2011, scientists reported that cosmic dust contains complex organic matter (""amorphous organic solids with a mixed aromatic–aliphatic structure"") that could be created naturally, and rapidly, by stars.On August 14, 2014, scientists announced the collection of possible interstellar dust particles from the Stardust spacecraft since returning to Earth in 2006.