Comets and astrobiology
... Comets are leftovers of the formation of planets in the Solar System. They formed in the first Myrs in the colder part of the protosolar nebula, where the temperature was low enough for water ice to condense, embedding “dust” particles made of organic and/ or mineral material. The resulting “dirty s ...
... Comets are leftovers of the formation of planets in the Solar System. They formed in the first Myrs in the colder part of the protosolar nebula, where the temperature was low enough for water ice to condense, embedding “dust” particles made of organic and/ or mineral material. The resulting “dirty s ...
Star formation rates from young-star counts and the structure of the
... Evans et al. (2009) and Lada et al. (2010) present the total SFRs based on young stellar object (YSO) candidates, identified from their mid-IR excess using Spitzer and compare those to molecular cloud masses derived using extinction maps for ∼10 nearby molecular clouds. These studies show that there ...
... Evans et al. (2009) and Lada et al. (2010) present the total SFRs based on young stellar object (YSO) candidates, identified from their mid-IR excess using Spitzer and compare those to molecular cloud masses derived using extinction maps for ∼10 nearby molecular clouds. These studies show that there ...
Debris disks and the search for life in the universe Gianni Cataldi
... medium (ISM). By mass, the ISM consists of 99% gas and 1% dust (Boulanger et al. 2000). The gas is composed of hydrogen (∼70% by mass) and helium (∼28%), the rest being heavier elements referred to as metals in astronomy. The ISM is far from homogeneous. Temperature and density vary considerably for ...
... medium (ISM). By mass, the ISM consists of 99% gas and 1% dust (Boulanger et al. 2000). The gas is composed of hydrogen (∼70% by mass) and helium (∼28%), the rest being heavier elements referred to as metals in astronomy. The ISM is far from homogeneous. Temperature and density vary considerably for ...
A trio of metalrich dust and gas discs found orbiting candidate white
... emissions consistent with warm circumstellar dust. These latter targets have spectral energy distributions similar to known dusty white dwarfs with high fractional infrared luminosities (thus the K-band excesses). Optical spectroscopy reveals the stars with disc-like excesses are polluted with heavy ...
... emissions consistent with warm circumstellar dust. These latter targets have spectral energy distributions similar to known dusty white dwarfs with high fractional infrared luminosities (thus the K-band excesses). Optical spectroscopy reveals the stars with disc-like excesses are polluted with heavy ...
Evolution of the Highest Redshift Quasars
... Large cosmic variance in deep field data Galaxy luminosity function at high-z ...
... Large cosmic variance in deep field data Galaxy luminosity function at high-z ...
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... and compare it with both the early and the present Solar System. The disk has very little gas and therefore is more evolved and older than the primordial solar nebulae, which persist for 1–10 Myr. We concentrate on the observed optical properties, spatial and size distribution, mineralogy, and physi ...
... and compare it with both the early and the present Solar System. The disk has very little gas and therefore is more evolved and older than the primordial solar nebulae, which persist for 1–10 Myr. We concentrate on the observed optical properties, spatial and size distribution, mineralogy, and physi ...
Debris Disks: Seeing Dust, Thinking of Planetesimals and Planets
... Mustill & Wyatt, 2009). Further possibilities which, however, are not considered typical for the majority of the disks, include “fast ignition” by the abrupt injection of a planet (suggestively of Neptune masses) into the disk after planet-planet scattering (Raymond et al., 2009) or external events ...
... Mustill & Wyatt, 2009). Further possibilities which, however, are not considered typical for the majority of the disks, include “fast ignition” by the abrupt injection of a planet (suggestively of Neptune masses) into the disk after planet-planet scattering (Raymond et al., 2009) or external events ...
Circumstellar dust emission from nearby Solar
... imperfect balance in the ratioing process. For further explanation, see text.” ...
... imperfect balance in the ratioing process. For further explanation, see text.” ...
Migrating Dust Particles
... size they drifted towards the Sun. This material was later accreted to planetesimals which are held together by self-gravity. As the planetesimals extend their gravitational range they have a run-away growth towards becoming planets. In this step the planetesimals grow more the larger they get. This ...
... size they drifted towards the Sun. This material was later accreted to planetesimals which are held together by self-gravity. As the planetesimals extend their gravitational range they have a run-away growth towards becoming planets. In this step the planetesimals grow more the larger they get. This ...
Document
... about 10 light-years across. 2. The disk. The part of the pancake outside the bulge is called the Galactic disk. It extends 45,000 light-years or so out from the center of our Galaxy. The Sun is located about one half to two thirds of the way out. The disk is very thin— 2 per cent of its width—like ...
... about 10 light-years across. 2. The disk. The part of the pancake outside the bulge is called the Galactic disk. It extends 45,000 light-years or so out from the center of our Galaxy. The Sun is located about one half to two thirds of the way out. The disk is very thin— 2 per cent of its width—like ...
The composition and nature of the dust shell surrounding the binary
... in the Tycho catalogue). The correct identifications should be HD 302821 and CPD -58◦ 2154. The central star was classified as a G2 supergiant by Garcı́aLario et al. (1994). The combination of a cool central star with low surface gravity and a relatively warm (i.e. young) detached dust shell is typi ...
... in the Tycho catalogue). The correct identifications should be HD 302821 and CPD -58◦ 2154. The central star was classified as a G2 supergiant by Garcı́aLario et al. (1994). The combination of a cool central star with low surface gravity and a relatively warm (i.e. young) detached dust shell is typi ...
UvA-DARE (Digital Academic Repository)
... For thousands of generations people have looked up to the night sky at the stars. But only in the modern scientific age have we begun to understand what it is that we see in the night sky, and what we can learn from it. Most importantly, we have learned that the stars in the sky are glowing balls of ...
... For thousands of generations people have looked up to the night sky at the stars. But only in the modern scientific age have we begun to understand what it is that we see in the night sky, and what we can learn from it. Most importantly, we have learned that the stars in the sky are glowing balls of ...
The major properties of the Interstellar Medium (ISM) are described
... interstellar medium various kinds of regions which are distinguishable by some combination of that temperature, density, chemical make up. Temperatures in the interstellar medium range from about 10 degrees above absolute 0 up to over one million degrees. The densities are much lower, covering a ran ...
... interstellar medium various kinds of regions which are distinguishable by some combination of that temperature, density, chemical make up. Temperatures in the interstellar medium range from about 10 degrees above absolute 0 up to over one million degrees. The densities are much lower, covering a ran ...
Dynamics of small bodies in planetary systems
... [92]. Naturally, the fact that these disks have inner holes similar in size to the planetary system in our solar system leads to the intriguing possibility that there is an (as yet) unseen planetary system sweeping these regions free of both planetesimals and dust. I will return to the putative plan ...
... [92]. Naturally, the fact that these disks have inner holes similar in size to the planetary system in our solar system leads to the intriguing possibility that there is an (as yet) unseen planetary system sweeping these regions free of both planetesimals and dust. I will return to the putative plan ...
12-iim fine-structure emission line and continuum images of G333.6
... (i.e. Ne iii producing) photons for the above stellar parameters. The photon flux is also a function of R. Rubin et al. (1994) estimated that, in order to reproduce the observed FIR flux, the central star (if single) in G333.6-0.2 would have to be as large as 12,, = 30.8 R o . The photoionization cr ...
... (i.e. Ne iii producing) photons for the above stellar parameters. The photon flux is also a function of R. Rubin et al. (1994) estimated that, in order to reproduce the observed FIR flux, the central star (if single) in G333.6-0.2 would have to be as large as 12,, = 30.8 R o . The photoionization cr ...
large particles in active asteroid p/2010 a2
... We computed models to follow the motion of spherical particles (density ρ = 3000 kg m−3 ) under the action of solar gravity and radiation pressure. In these models, the ratio of the radiation pressure acceleration to gravitational acceleration is β = 0.2 aµ−1 , where aµ is the particle radius in mic ...
... We computed models to follow the motion of spherical particles (density ρ = 3000 kg m−3 ) under the action of solar gravity and radiation pressure. In these models, the ratio of the radiation pressure acceleration to gravitational acceleration is β = 0.2 aµ−1 , where aµ is the particle radius in mic ...
Galactic Chemical Evolution and the Oxygen Isotopic Composition
... between δ17O and δ18O in the ISM need not necessarily reflect an O isotopic gradient, and any slope-one galactocentric gradient need not correspond to evolution in time. Instead, increasing 17O/18O is consistent both with observational data from molecular clouds and with modeling of the compositions ...
... between δ17O and δ18O in the ISM need not necessarily reflect an O isotopic gradient, and any slope-one galactocentric gradient need not correspond to evolution in time. Instead, increasing 17O/18O is consistent both with observational data from molecular clouds and with modeling of the compositions ...
SciPoster_Jan2009
... Our team observed two Lynds clouds (LDN 425 and LDN 981) using the Spitzer Space Telescope IRAC (3.6, 4.5, 5.8, and 8 microns), and MIPS (24 microns). A preliminary literature search provided IRAS data indicating star formation may be taking place in LDN 425 and LDN 981. The goals of this project we ...
... Our team observed two Lynds clouds (LDN 425 and LDN 981) using the Spitzer Space Telescope IRAC (3.6, 4.5, 5.8, and 8 microns), and MIPS (24 microns). A preliminary literature search provided IRAS data indicating star formation may be taking place in LDN 425 and LDN 981. The goals of this project we ...
... Chondrites are meteorites that contain millimeter-sized objects called chondrules. In the 1960s and 70s, there was great hope that chondrules formed directly from the cloud of gas and dust that surrounded the Sun as it was still forming. The intellectual battle was between direct condensation from t ...
A Search for Exozodiacal Dust and Faint Companions near Sirius
... the circular masked regions. The symmetry planes of the model disks are inclined 30¡ from edge-on. The dust densities in these have been enhanced to more than 105 times solar levels, so they are marginally discernible from the residuals from the point-spread function (PSF) subtraction. We used these ...
... the circular masked regions. The symmetry planes of the model disks are inclined 30¡ from edge-on. The dust densities in these have been enhanced to more than 105 times solar levels, so they are marginally discernible from the residuals from the point-spread function (PSF) subtraction. We used these ...
Emission from dust in galaxies: Metallicity dependence
... Abstract. Infrared (IR) dust emission from galaxies is frequently used as an indicator of star formation rate (SFR). However, the effect of the dust-to-gas ratio (i.e., amount of the dust) on the conversion law from IR luminosity to SFR has not so far been considered. Then, in this paper, we present ...
... Abstract. Infrared (IR) dust emission from galaxies is frequently used as an indicator of star formation rate (SFR). However, the effect of the dust-to-gas ratio (i.e., amount of the dust) on the conversion law from IR luminosity to SFR has not so far been considered. Then, in this paper, we present ...
The Kuiper Belt and Other Debris Disks - UCLA
... they are certainly not solid bodies but are merely composed of molecules which, if they were much colder, would be simple ices. In terms of their mode of formation, the difference between the ice giants and the gas giants may be largely one of timescale. It is widely thought that the ice giants corr ...
... they are certainly not solid bodies but are merely composed of molecules which, if they were much colder, would be simple ices. In terms of their mode of formation, the difference between the ice giants and the gas giants may be largely one of timescale. It is widely thought that the ice giants corr ...
DUSTY CIRCUMSTELLAR DISKS B. Zuckerman
... giants and white dwarfs. Surprisingly, a small percentage of such stars appears to be surrounded by orbiting dusty disks. The origins of most of these disks are mysteries whose eventual understanding will, no doubt, reveal interesting and important astronomical phenomena. Following discussion of ste ...
... giants and white dwarfs. Surprisingly, a small percentage of such stars appears to be surrounded by orbiting dusty disks. The origins of most of these disks are mysteries whose eventual understanding will, no doubt, reveal interesting and important astronomical phenomena. Following discussion of ste ...
SUB-KILOPARSEC IMAGING OF COOL MOLECULAR GAS IN
... conducted by the South Pole Telsecope (SPT; Carlstrom et al. 2011; Vieira et al. 2010; Mocanu et al. 2013) and Herschel (Negrello et al. 2010; Wardlow et al. 2013) have discovered large numbers of lensed DSFGs. Subsequent spectroscopy and high-resolution imaging have confirmed that the large majorit ...
... conducted by the South Pole Telsecope (SPT; Carlstrom et al. 2011; Vieira et al. 2010; Mocanu et al. 2013) and Herschel (Negrello et al. 2010; Wardlow et al. 2013) have discovered large numbers of lensed DSFGs. Subsequent spectroscopy and high-resolution imaging have confirmed that the large majorit ...
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.