NSDL_WS_1_Astonomy
... http://www.compadre.org/Astronomy Hubble Space Telescope http://hubblesite.org International Year of Astronomy 2009 http://astronomy2009.us http://astronomy2009.org ...
... http://www.compadre.org/Astronomy Hubble Space Telescope http://hubblesite.org International Year of Astronomy 2009 http://astronomy2009.us http://astronomy2009.org ...
hwd_ewd_v3 - X-ray and Observational Astronomy Group
... The basis for understanding the nature of most stars is analysis of their optical spectra and classification according to the characteristics revealed. A number of physical processes can alter the atmospheric composition of a white dwarf as it cools. As noted by Schatzman4, the strong gravitational ...
... The basis for understanding the nature of most stars is analysis of their optical spectra and classification according to the characteristics revealed. A number of physical processes can alter the atmospheric composition of a white dwarf as it cools. As noted by Schatzman4, the strong gravitational ...
Molecular Cloud Evolution II. From cloud formation to the early
... and colder, its Jeans mass decreases substantially. Moreover, its own mass is increasing, so it rapidly becomes much more massive than its own Jeans mass. Also, as the cloud becomes more massive, its total gravitational energy (in absolute value) |Eg | increases substantially, and eventually overcom ...
... and colder, its Jeans mass decreases substantially. Moreover, its own mass is increasing, so it rapidly becomes much more massive than its own Jeans mass. Also, as the cloud becomes more massive, its total gravitational energy (in absolute value) |Eg | increases substantially, and eventually overcom ...
Astronomy Astrophysics
... near dawn, he considered the emission spike as an artefact from residual night sky emission. We inspected Reid’s spectrum but could not find any other residual night sky emission throughout the entire spectrum. We noticed, however, that the line core of Hβ displays a slight asymmetry. The Hα profile ...
... near dawn, he considered the emission spike as an artefact from residual night sky emission. We inspected Reid’s spectrum but could not find any other residual night sky emission throughout the entire spectrum. We noticed, however, that the line core of Hβ displays a slight asymmetry. The Hα profile ...
Astronomy
... • Some oceans are 25-30 degrees celsius all year round • Greenhouse effect also counters this ...
... • Some oceans are 25-30 degrees celsius all year round • Greenhouse effect also counters this ...
Hot subdwarf stars-galactic orbits and distribution perpendicular to
... Since these proper motions are based on only one first epoch position, we are not able to calculate proper motion errors. An indication of the proper motion uncertainty may be the uncertainty of the zero point shift, representing a lower limit to our errors. In Table 2, δ(µα cosδ) and δ(µδ ) designa ...
... Since these proper motions are based on only one first epoch position, we are not able to calculate proper motion errors. An indication of the proper motion uncertainty may be the uncertainty of the zero point shift, representing a lower limit to our errors. In Table 2, δ(µα cosδ) and δ(µδ ) designa ...
Galaxies
... Meaning of Hubble Law • Distant objects are moving away from us ! Universe is expanding • This was predicted by Einstein’s general theory of relativity (~1915) but Einstein thought it was a mistake in the theory prior to results from Hubble and others observations in 1926-1935 • Measurement of H ...
... Meaning of Hubble Law • Distant objects are moving away from us ! Universe is expanding • This was predicted by Einstein’s general theory of relativity (~1915) but Einstein thought it was a mistake in the theory prior to results from Hubble and others observations in 1926-1935 • Measurement of H ...
File
... This unusual long arm shows lots of young blue star clusters. But NGC 772 also possesses many weak, tightly coiled arms which, although well formed, are relatively smooth, indicating only a small current rate of star formation. The relatively smooth multiple arms on the opposite side from the promin ...
... This unusual long arm shows lots of young blue star clusters. But NGC 772 also possesses many weak, tightly coiled arms which, although well formed, are relatively smooth, indicating only a small current rate of star formation. The relatively smooth multiple arms on the opposite side from the promin ...
THE MONTHLY SKY GUIDE, SIXTH EDITION
... streak of light dash across the sky like a cosmic laser beam, lasting no more than a second or so. This is a meteor, popularly termed a shooting star. Do not misidentify shooting stars with satellites or high-flying aeroplanes, which look like moving stars but drift at a more leisurely pace. Despite ...
... streak of light dash across the sky like a cosmic laser beam, lasting no more than a second or so. This is a meteor, popularly termed a shooting star. Do not misidentify shooting stars with satellites or high-flying aeroplanes, which look like moving stars but drift at a more leisurely pace. Despite ...
Head–tail Galaxies: beacons of high
... on the major merger A3125/A3128 yields 582 redshifts. When compiling a catalogue from several different sources which have overlapping observations of the same galaxies, care must be taken to ensure that individual objects do not appear more than once in the final catalogue or that close, but indepe ...
... on the major merger A3125/A3128 yields 582 redshifts. When compiling a catalogue from several different sources which have overlapping observations of the same galaxies, care must be taken to ensure that individual objects do not appear more than once in the final catalogue or that close, but indepe ...
silicon and oxygen abundances in planet-host stars
... elements. They observe no difference in the overall trends of [X/Fe] between planet hosts and their volume-limited sample of stars without any known planetary-mass companions. Based on their results, stars with planets appear to be indistinguishable from other field stars and seem to simply lie on t ...
... elements. They observe no difference in the overall trends of [X/Fe] between planet hosts and their volume-limited sample of stars without any known planetary-mass companions. Based on their results, stars with planets appear to be indistinguishable from other field stars and seem to simply lie on t ...
Surface Gravity as a Diagnostic ... Youth Cameron Higby-Naquin Advisor: Eric Jensen
... field since the discovery of the first recognizably pre-main-sequence (PMS) stars by Joy in the 1940's. Astronomers created a class of variable stars called T Tauri Stars (TTS) when they discovered similar properties in all of them [2]. Later, it was determined that many of these properties signify ...
... field since the discovery of the first recognizably pre-main-sequence (PMS) stars by Joy in the 1940's. Astronomers created a class of variable stars called T Tauri Stars (TTS) when they discovered similar properties in all of them [2]. Later, it was determined that many of these properties signify ...
Triggered/sequential star formation? A multi
... with the molecular clump G18.93/m being IR dark from near-IR wavelength up to 160 μm. Spitzer composite images show an IR bubble spatially associated with G18.93-0.03. We use GRS 13 CO and IRAM 30 m H13 CO+ data to disentangle the large and small scale spatial structure of the region. From ATLASGAL ...
... with the molecular clump G18.93/m being IR dark from near-IR wavelength up to 160 μm. Spitzer composite images show an IR bubble spatially associated with G18.93-0.03. We use GRS 13 CO and IRAM 30 m H13 CO+ data to disentangle the large and small scale spatial structure of the region. From ATLASGAL ...
The Physics of Star Formation: Understanding the Youngest Protostars
... cloud cores. Most have only been detected at far{IR (e.g., 25 , 60m IRAS data) and sub{mm wavelengths. They appear to be protostars that have yet to accrete the bulk of their masses and are characterized by very cold (T 30 K), extended (r 1000 AU) envelopes and powerful bipolar out ows. The ...
... cloud cores. Most have only been detected at far{IR (e.g., 25 , 60m IRAS data) and sub{mm wavelengths. They appear to be protostars that have yet to accrete the bulk of their masses and are characterized by very cold (T 30 K), extended (r 1000 AU) envelopes and powerful bipolar out ows. The ...
Astro 102 Practice Test 3
... c. indicates that the sun's core is much hotter than expected. d. indicates the sun's core is convective. e. none of the above 6. The carbon-nitrogen-oxygen cycle a. operates at a slightly lower temperature than the proton-proton chain. b. is most efficient in a star less massive than the sun. c. oc ...
... c. indicates that the sun's core is much hotter than expected. d. indicates the sun's core is convective. e. none of the above 6. The carbon-nitrogen-oxygen cycle a. operates at a slightly lower temperature than the proton-proton chain. b. is most efficient in a star less massive than the sun. c. oc ...
Part IV: Stars
... interior, photons can only travel a fraction of a millimeter before “colliding” with an electron and deflecting into a new direction. So photons bounce around at random and only slowly make their way out of the Sun. Mathematical models use the observed composition and mass of the Sun, along with the ...
... interior, photons can only travel a fraction of a millimeter before “colliding” with an electron and deflecting into a new direction. So photons bounce around at random and only slowly make their way out of the Sun. Mathematical models use the observed composition and mass of the Sun, along with the ...
The dense gas mass fraction in the W51 cloud and its protoclusters
... 104 cm−3 , in the Galactic disk (Lada et al. 2010, who advocate a column density threshold corresponding to this density); note however that the threshold is smooth, not a step function as implied by the term (Padoan et al. 2014). The dense gas mass fraction has been measured for various definitions ...
... 104 cm−3 , in the Galactic disk (Lada et al. 2010, who advocate a column density threshold corresponding to this density); note however that the threshold is smooth, not a step function as implied by the term (Padoan et al. 2014). The dense gas mass fraction has been measured for various definitions ...
103-122
... necessarily compatible with the theories of Galactic chemical evolution. If the αelements and the iron-group are synthesized in different stars, and gas clouds in the early Galaxy were poorly mixed, one may expect, as earlier and earlier generations of stars are examined, [α/Fe] to show an increasin ...
... necessarily compatible with the theories of Galactic chemical evolution. If the αelements and the iron-group are synthesized in different stars, and gas clouds in the early Galaxy were poorly mixed, one may expect, as earlier and earlier generations of stars are examined, [α/Fe] to show an increasin ...
galaxy formation and evolution - Yale Astronomy
... we now observe may then just represent the smallest structures that have survived as discrete units (Peebles 1974). The detailed way in which structure develops and galaxies form depends on the nature of the initial density fluctuation spectrum, so it is important to try to constrain the form of thi ...
... we now observe may then just represent the smallest structures that have survived as discrete units (Peebles 1974). The detailed way in which structure develops and galaxies form depends on the nature of the initial density fluctuation spectrum, so it is important to try to constrain the form of thi ...
Do We Know of Any Maunder Minimum Stars?
... Studies of the star formation history of the galaxy, searches for extrasolar planets, and studies of the Sun as a star often benefit from the ability to determine the age of sun-like stars. But, because stars change very little during their lifetime on the main sequence, determining their age is dif ...
... Studies of the star formation history of the galaxy, searches for extrasolar planets, and studies of the Sun as a star often benefit from the ability to determine the age of sun-like stars. But, because stars change very little during their lifetime on the main sequence, determining their age is dif ...
hr diagrams of star clusters
... Star clusters are groups of stars which, astronomers believe, were born together at roughly the same time from the same cloud of interstellar gas. HR diagrams are particularly useful for studying the characteristics of such clusters. The stars in a cluster have a range of stellar masses, from very m ...
... Star clusters are groups of stars which, astronomers believe, were born together at roughly the same time from the same cloud of interstellar gas. HR diagrams are particularly useful for studying the characteristics of such clusters. The stars in a cluster have a range of stellar masses, from very m ...
The absence of CO from the dust peak around ϵ Eri
... present during the epoch of star and planet formation should have been removed (e.g. Lissauer 1993). Submillimetre images of the dust around the nearest such stars – Vega itself (α Lyrae), Fomalhaut (α Piscis Austrini), β Pictoris and Eri (Greaves et al. 1998; Holland et al. 1998, 2003) – show dis ...
... present during the epoch of star and planet formation should have been removed (e.g. Lissauer 1993). Submillimetre images of the dust around the nearest such stars – Vega itself (α Lyrae), Fomalhaut (α Piscis Austrini), β Pictoris and Eri (Greaves et al. 1998; Holland et al. 1998, 2003) – show dis ...
THE PERIOD OF ROTATION OF THE SUN
... Star clusters are groups of stars which, astronomers believe, were born together at roughly the same time from the same cloud of interstellar gas. HR diagrams are particularly useful for studying the characteristics of such clusters. The stars in a cluster have a range of stellar masses, from very m ...
... Star clusters are groups of stars which, astronomers believe, were born together at roughly the same time from the same cloud of interstellar gas. HR diagrams are particularly useful for studying the characteristics of such clusters. The stars in a cluster have a range of stellar masses, from very m ...
HR DIAGRAMS OF STAR CLUSTERS
... Star clusters are groups of stars which, astronomers believe, were born together at roughly the same time from the same cloud of interstellar gas. HR diagrams are particularly useful for studying the characteristics of such clusters. The stars in a cluster have a range of stellar masses, from very m ...
... Star clusters are groups of stars which, astronomers believe, were born together at roughly the same time from the same cloud of interstellar gas. HR diagrams are particularly useful for studying the characteristics of such clusters. The stars in a cluster have a range of stellar masses, from very m ...
A COMPREHENSIVE COMPARISON OF THE SUN TO
... 53% 2% of the stars in the thin disk of our Galaxy. Overplotted is the cosmic SFR derived by Hopkins & Beacom (2006). According to this distribution with a median 1=2 ¼ 9:15 Gyr, the Sun was born after 86% 5% of the stars that have ever been born. The Galactic and cosmic SFRs are different beca ...
... 53% 2% of the stars in the thin disk of our Galaxy. Overplotted is the cosmic SFR derived by Hopkins & Beacom (2006). According to this distribution with a median 1=2 ¼ 9:15 Gyr, the Sun was born after 86% 5% of the stars that have ever been born. The Galactic and cosmic SFRs are different beca ...
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.