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... the photodissociation rate for H2 O in exoplanets with solar-type and M dwarf host stars including the observed UV fluxes and Lyman-α corrected for interstellar absorption to evaluate the H2 O loss rate. At this time, however, there are very few disequilibrium chemistry calculations that include obs ...
... the photodissociation rate for H2 O in exoplanets with solar-type and M dwarf host stars including the observed UV fluxes and Lyman-α corrected for interstellar absorption to evaluate the H2 O loss rate. At this time, however, there are very few disequilibrium chemistry calculations that include obs ...
sections 16-18 instructor notes
... stars chosen spectroscopically will include objects of various origins, unless the group is so young that the stars have not had time to travel far from their places of formation. The increasing density gradient in the disk of the Galaxy towards the Galactic centre implies that the majority of stars ...
... stars chosen spectroscopically will include objects of various origins, unless the group is so young that the stars have not had time to travel far from their places of formation. The increasing density gradient in the disk of the Galaxy towards the Galactic centre implies that the majority of stars ...
REVIEW Early star-forming galaxies and the reionization of the Universe
... galaxies. Second, fQ and fesc must be observationally estimated by determining the relative effects of stars, dust and nebular emission on the rest-frame ultraviolet region of high-redshift galaxy spectral energy distributions or by direct observations in the Lyman continuum at lower redshift. To re ...
... galaxies. Second, fQ and fesc must be observationally estimated by determining the relative effects of stars, dust and nebular emission on the rest-frame ultraviolet region of high-redshift galaxy spectral energy distributions or by direct observations in the Lyman continuum at lower redshift. To re ...
STAR FORMATION IN ISOLATED DISK GALAXIES. II. SCHMIDT
... a Schmidt law with power-law index of 1.3. However, these simulations included only stars and gas, and no dark matter. More recently, Kravtsov (2003) reproduced the global Schmidt law using self-consistent cosmological simulations of high-redshift galaxy formation. He argued that the global Schmidt ...
... a Schmidt law with power-law index of 1.3. However, these simulations included only stars and gas, and no dark matter. More recently, Kravtsov (2003) reproduced the global Schmidt law using self-consistent cosmological simulations of high-redshift galaxy formation. He argued that the global Schmidt ...
the inclination of the dwarf irregular galaxy
... Recent studies indicate that galactic disks stabilize to a constant stability parameter across the optical galaxy (Meurer et al. 2013; Zheng et al. 2013), lending support to the phenomenon of self-regulation by star formation, as suggested by Quirk (1972). However, although the value of the Qg -para ...
... Recent studies indicate that galactic disks stabilize to a constant stability parameter across the optical galaxy (Meurer et al. 2013; Zheng et al. 2013), lending support to the phenomenon of self-regulation by star formation, as suggested by Quirk (1972). However, although the value of the Qg -para ...
Searching for the oldest, most metal-poor stars in the SkyMapper Survey
... been an evolution of element production. The first stars were formed from only hydrogen and helium. However, over time, the amount of elements heavier than those two has increased with each new generation of stars. This research examined absorption-line spectra of 215 stars in the Milky Way that pos ...
... been an evolution of element production. The first stars were formed from only hydrogen and helium. However, over time, the amount of elements heavier than those two has increased with each new generation of stars. This research examined absorption-line spectra of 215 stars in the Milky Way that pos ...
A dust ring around Epsilon Eridani: analogue to the young Solar
... per unit mass than individual grains). The ǫ Eri system could thus be analogous to the young Solar System, seen when planet formation is ongoing or complete, but some dust is still present at all radii out to about 36′′ (115 AU). The age of the star is not well-defined, but can be estimated from the ...
... per unit mass than individual grains). The ǫ Eri system could thus be analogous to the young Solar System, seen when planet formation is ongoing or complete, but some dust is still present at all radii out to about 36′′ (115 AU). The age of the star is not well-defined, but can be estimated from the ...
Facilitator`s Guide
... People young and old have always been fascinated and awed by imagining how large and how old the Universe is and how far away the stars and the galaxies are from us. Today, many simply accept these huge numbers they hear as fact, without wondering how they are ascertained. In a typical introductory ...
... People young and old have always been fascinated and awed by imagining how large and how old the Universe is and how far away the stars and the galaxies are from us. Today, many simply accept these huge numbers they hear as fact, without wondering how they are ascertained. In a typical introductory ...
Galaxy formation in the Planck cosmology - II. Star
... Voort (2015). The difference between the two reflects the merger history of galaxies. The term SFH is often loosely used in papers without being defined. Observationally, the only direct measure of SFHs corresponds to that described in this paper, i.e. the distribution of formation times of all the ...
... Voort (2015). The difference between the two reflects the merger history of galaxies. The term SFH is often loosely used in papers without being defined. Observationally, the only direct measure of SFHs corresponds to that described in this paper, i.e. the distribution of formation times of all the ...
ISA_lecture01 - School of Physics
... Astrophysics has long been one of the driving forces for the advancement of physics in general. It has been closely linked to advances in quantum mechanics and nuclear physics in particular. Stellar astrophysics in particular is also firmly rooted in classical physics - the familiar laws of mechanic ...
... Astrophysics has long been one of the driving forces for the advancement of physics in general. It has been closely linked to advances in quantum mechanics and nuclear physics in particular. Stellar astrophysics in particular is also firmly rooted in classical physics - the familiar laws of mechanic ...
black holes can play a constructive role as well
... length, and the rotational velocity of the cloud supports it from collapsing towards the nucleus (Schiminovich et al. 1994). Moreover, the stellar age of ∼ 10 − 15 Myrs (Rejkuba et al. 2002) is consistent with the crossing time of the cloud across the radio jet, and the ionized gas velocities within ...
... length, and the rotational velocity of the cloud supports it from collapsing towards the nucleus (Schiminovich et al. 1994). Moreover, the stellar age of ∼ 10 − 15 Myrs (Rejkuba et al. 2002) is consistent with the crossing time of the cloud across the radio jet, and the ionized gas velocities within ...
Entropy
... because, according to the modern concepts, stars of the same cluster are formed from the same molecular cloud and therefore have the same age (which is relatively easy to determine) and the same composition (e.g., metallicity [Fe/H]). Furthermore, cluster stars are located at the same distance from ...
... because, according to the modern concepts, stars of the same cluster are formed from the same molecular cloud and therefore have the same age (which is relatively easy to determine) and the same composition (e.g., metallicity [Fe/H]). Furthermore, cluster stars are located at the same distance from ...
Journey through the cosmos
... of our own Galaxy with the naked eye. The darker the skies, the more stars you can see. Of course, there are billions more stars but they are so far away. You can see stars because they are luminous, which means that they give out their own energy as light. Each galaxy is a collection of many millio ...
... of our own Galaxy with the naked eye. The darker the skies, the more stars you can see. Of course, there are billions more stars but they are so far away. You can see stars because they are luminous, which means that they give out their own energy as light. Each galaxy is a collection of many millio ...
Star Formation in the Orion Nebula II: Gas, Dust, Proplyds and
... Radial velocities have been determined across the face of the Huygens region with spatial resolutions of a few seconds of arc and velocity resolutions of better than 10 km s−1 (Doi et al. 2004; Henney et al. 2007; Garcı́a-Dı́az & Henney 2007; Garcı́aDı́az et al. 2008). In the central portion of the ...
... Radial velocities have been determined across the face of the Huygens region with spatial resolutions of a few seconds of arc and velocity resolutions of better than 10 km s−1 (Doi et al. 2004; Henney et al. 2007; Garcı́a-Dı́az & Henney 2007; Garcı́aDı́az et al. 2008). In the central portion of the ...
Entropy Production of Main-Sequence Stars
... and generalize gravitation theories, etc. (see, e.g., [6–10]). The majority of the papers, being strictly theoretical, place principal emphasis on functional relations between variables established through the analysis of entropy and its production. There are almost no quantitative calculations of e ...
... and generalize gravitation theories, etc. (see, e.g., [6–10]). The majority of the papers, being strictly theoretical, place principal emphasis on functional relations between variables established through the analysis of entropy and its production. There are almost no quantitative calculations of e ...
Sample
... neutron star with a mass that is three times greater than the mass of the Sun cannot hold itself up under its own gravity and will compress into an infinitesimal point called a singularity, where the original matter is lost from view forever and only gravity remains, thus forming what is referred to ...
... neutron star with a mass that is three times greater than the mass of the Sun cannot hold itself up under its own gravity and will compress into an infinitesimal point called a singularity, where the original matter is lost from view forever and only gravity remains, thus forming what is referred to ...
Notes for Class 5, February 16
... Built great observatories on his island Fights, duels, possibly died from being drunk, but also careful astronomical measurements • Convinced astronomy needed good measurements ...
... Built great observatories on his island Fights, duels, possibly died from being drunk, but also careful astronomical measurements • Convinced astronomy needed good measurements ...
Dr. Amanda Karakas and Prof. John Lattanzio
... supernova (> 10 solar masses); 2. Stars that evolve through the first and asymptotic giant branches (< 10 solar masses) ...
... supernova (> 10 solar masses); 2. Stars that evolve through the first and asymptotic giant branches (< 10 solar masses) ...
Examining the M67 Classification as an Open Cluster
... in the galactic field the total internal energy of a cluster should rise, ultimately leading to a complete breakup of the cluster. It turned out that the characteristic time for this process of destruction of dense stellar clusters is at most 1010 yr. Spitzer [16,17] has calculated the increase of e ...
... in the galactic field the total internal energy of a cluster should rise, ultimately leading to a complete breakup of the cluster. It turned out that the characteristic time for this process of destruction of dense stellar clusters is at most 1010 yr. Spitzer [16,17] has calculated the increase of e ...
Ch 11a (Measuring Stars 10-28-10)
... IV. Stellar sizes (radius) Luminosity is proportional to surface area (how large) x temperature (how hot): L= 4R2T4 If we can measure the Luminosity and the temperature of a star we can tell how large its ...
... IV. Stellar sizes (radius) Luminosity is proportional to surface area (how large) x temperature (how hot): L= 4R2T4 If we can measure the Luminosity and the temperature of a star we can tell how large its ...
in BRIGHTEST STARS
... the figure of 3,230 light-years, whereas the refined data yield just over 1,400 light-years. At any of these estimates distances, Deneb is one of the farthest stars the unaided human eye can see. It is so far, that the light that reaches the Earth today started on its journey well more than 1,000 ye ...
... the figure of 3,230 light-years, whereas the refined data yield just over 1,400 light-years. At any of these estimates distances, Deneb is one of the farthest stars the unaided human eye can see. It is so far, that the light that reaches the Earth today started on its journey well more than 1,000 ye ...
The star-forming content of the W3 giant molecular cloud
... distribution in the detected clump sample depends somewhat on assumptions of dust temperature and is not a simple, single power law but contains significant structure at intermediate masses. This structure is likely to be due to crowding of sources near or below the spatial resolution of the observa ...
... distribution in the detected clump sample depends somewhat on assumptions of dust temperature and is not a simple, single power law but contains significant structure at intermediate masses. This structure is likely to be due to crowding of sources near or below the spatial resolution of the observa ...
Institute for Astrophysical Research Seminar Series
... Factory Trawling the X-ray Sky: The Chandra Multiwavelength Project ...
... Factory Trawling the X-ray Sky: The Chandra Multiwavelength Project ...
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.