www.astro.org.uk www.facebook.com/Stra ordAstro www.twi er.com
... measurements of cosmological distances. The astronomers worked out the distance to the Large Magellanic Cloud by observing rare close pairs of stars, known as eclipsing binaries . As these stars orbit each other they pass in front of each other. When this happens, as seen from Earth, the total brigh ...
... measurements of cosmological distances. The astronomers worked out the distance to the Large Magellanic Cloud by observing rare close pairs of stars, known as eclipsing binaries . As these stars orbit each other they pass in front of each other. When this happens, as seen from Earth, the total brigh ...
The Evening Sky Map
... Conjunction – An alignment of two celestial bodies such that they present the least angular separation as viewed from Earth. Constellation – A defined area of the sky containing a star pattern. Diffuse Nebula – A cloud of gas illuminated by nearby stars. Double Star – Two stars that appear close to ...
... Conjunction – An alignment of two celestial bodies such that they present the least angular separation as viewed from Earth. Constellation – A defined area of the sky containing a star pattern. Diffuse Nebula – A cloud of gas illuminated by nearby stars. Double Star – Two stars that appear close to ...
27B Star Life Cycle and the HR Diagram
... all of the known stars were put on their graph, several obvious groups became apparent. By examining the differences in these groups, later astronomers were able to realize that the groups were best described as stars in different periods in their life cycle, rather than completely different types o ...
... all of the known stars were put on their graph, several obvious groups became apparent. By examining the differences in these groups, later astronomers were able to realize that the groups were best described as stars in different periods in their life cycle, rather than completely different types o ...
Determination of kinetic energies of stars using Hipparcos data *
... that remains, can be explained by inaccuracy in mass N 1526 determination or other reasons and needs to studied in 7085 detail. In our opinion, there are two directions, in which the present paper can be extended: – The individual radial velocities can be used to obtain the spatial velocity for each ...
... that remains, can be explained by inaccuracy in mass N 1526 determination or other reasons and needs to studied in 7085 detail. In our opinion, there are two directions, in which the present paper can be extended: – The individual radial velocities can be used to obtain the spatial velocity for each ...
Life as a Low Mass Red Giant
... first, moving to Red Giant stage: The point where stars are just leaving the Main Sequence is called "main sequence turnoff" point. http://www.astro.ubc.ca/~scharein/a311/Sim.html The age of a cluster is just the main sequence lifetime of the stars at the main sequence turnoff • This is about the on ...
... first, moving to Red Giant stage: The point where stars are just leaving the Main Sequence is called "main sequence turnoff" point. http://www.astro.ubc.ca/~scharein/a311/Sim.html The age of a cluster is just the main sequence lifetime of the stars at the main sequence turnoff • This is about the on ...
Galaxy formation and evolution in the CDM model
... surprisingly mergers do play a major role in disk growth Gas-rich major mergers can build large disk galaxies rather than ellipticals! (see also Robertson et al. 2006) - (high) Orbital angular momentum converted into angular momentum of infalling gas during merger Mechanism clear in HI component, ...
... surprisingly mergers do play a major role in disk growth Gas-rich major mergers can build large disk galaxies rather than ellipticals! (see also Robertson et al. 2006) - (high) Orbital angular momentum converted into angular momentum of infalling gas during merger Mechanism clear in HI component, ...
How Many Stars in the Sky?
... 8. The truthful answer to how many stars are in the sky is that no one really knows, because there are just too many to count. Stars are not evenly spread out in our universe but instead group together in galaxies. Our Milky Way galaxy alone is made up of an estimated 100 thousand million (100,000,0 ...
... 8. The truthful answer to how many stars are in the sky is that no one really knows, because there are just too many to count. Stars are not evenly spread out in our universe but instead group together in galaxies. Our Milky Way galaxy alone is made up of an estimated 100 thousand million (100,000,0 ...
The University of Sydney Page
... Very low mass stars Very low mass stars (mass less than about 0.4 solar masses) are different in one important respect from heavier stars: their interiors are fully convective. The fused helium is stirred through the whole star, so it has the whole of its hydrogen mass to prolong its stay on the ma ...
... Very low mass stars Very low mass stars (mass less than about 0.4 solar masses) are different in one important respect from heavier stars: their interiors are fully convective. The fused helium is stirred through the whole star, so it has the whole of its hydrogen mass to prolong its stay on the ma ...
Using Photometric Data to Derive an HR Diagram
... That’s where STAR CLUSTERS come in! All the stars in a cluster are at the same distance from us (neglecting the depth of the cluster itself, which is tiny compared with its overall distance from us). All the stars in a cluster are the same absolute age, although at different stages of evolution, dep ...
... That’s where STAR CLUSTERS come in! All the stars in a cluster are at the same distance from us (neglecting the depth of the cluster itself, which is tiny compared with its overall distance from us). All the stars in a cluster are the same absolute age, although at different stages of evolution, dep ...
Galactic Evolution - Harvard-Smithsonian Center for Astrophysics
... stars existing today, hence very much shorter lived than any stars now known. Such pure gas, lacking in C and O that normally help clouds to cool and condense, would have needed more mass to contract than stars typically now, >10 Gy after the bang. Without those heavy-element cooling agents, the ear ...
... stars existing today, hence very much shorter lived than any stars now known. Such pure gas, lacking in C and O that normally help clouds to cool and condense, would have needed more mass to contract than stars typically now, >10 Gy after the bang. Without those heavy-element cooling agents, the ear ...
white dwarfs, neutron stars, black hole
... and very dramatic, in store for stars which are some 5 or more times as massive as our Sun. After the outer layers of the star have swollen into a red supergiant (i.e., a very big red giant), the core begins to yield to gravity and starts to shrink. As it shrinks, it grows hotter and denser, and a n ...
... and very dramatic, in store for stars which are some 5 or more times as massive as our Sun. After the outer layers of the star have swollen into a red supergiant (i.e., a very big red giant), the core begins to yield to gravity and starts to shrink. As it shrinks, it grows hotter and denser, and a n ...
Lecture12
... Cepheid variable stars are very luminous and can be observed over very large distances. Why are such stars important to astronomers? A. They confirm the theory of nuclear fusion as the energy source for stars. B. They can be used as distance indicators because their luminosity can be determined fro ...
... Cepheid variable stars are very luminous and can be observed over very large distances. Why are such stars important to astronomers? A. They confirm the theory of nuclear fusion as the energy source for stars. B. They can be used as distance indicators because their luminosity can be determined fro ...
Lecture 11: Stars, HR diagram.
... If we have a higher mass star, how can we keep it from collapsing under its own weight? The pressure needs to balance the gravitational force. Higher mass = higher core pressure and higher core temperature fusion rate increases until it supports the star’s mass Lower mass = lower core pressure and l ...
... If we have a higher mass star, how can we keep it from collapsing under its own weight? The pressure needs to balance the gravitational force. Higher mass = higher core pressure and higher core temperature fusion rate increases until it supports the star’s mass Lower mass = lower core pressure and l ...
Chapter 12 - Indiana State University
... ionized state • A stars have just the right temperature to put electrons into hydrogen’s 2nd energy level, which results in strong absorption lines in the visible • F, G, and K stars are of a low enough temperature to show absorption lines of metals such as calcium and iron, elements that are typica ...
... ionized state • A stars have just the right temperature to put electrons into hydrogen’s 2nd energy level, which results in strong absorption lines in the visible • F, G, and K stars are of a low enough temperature to show absorption lines of metals such as calcium and iron, elements that are typica ...
Images from the Las Cumbres Observatory Global Telescope
... The name ‘Cancer’ means ‘the crab’ in Latin. It is the faintest of the 12 zodiac constellations and contains some famous DSOs: the open cluster Praesepe, aka the Beehive Cluster (M44), and the open cluster M67. Cancer does not have any stars brighter than 4th mag. Stars α, δ, and γ Cancri lie close ...
... The name ‘Cancer’ means ‘the crab’ in Latin. It is the faintest of the 12 zodiac constellations and contains some famous DSOs: the open cluster Praesepe, aka the Beehive Cluster (M44), and the open cluster M67. Cancer does not have any stars brighter than 4th mag. Stars α, δ, and γ Cancri lie close ...
3.7 Isotope Effect - Institute for Astronomy | ETH
... The solar isotope ratios, e.g. 12C/13C = 80, corresponds to the chemical composition of our galaxy 4.6 × 109 years ago at the birthplace of the Sun. A comparison with today’s isotope ratios in the interstellar medium provides important clues on the production rate of heavier elements in stars and al ...
... The solar isotope ratios, e.g. 12C/13C = 80, corresponds to the chemical composition of our galaxy 4.6 × 109 years ago at the birthplace of the Sun. A comparison with today’s isotope ratios in the interstellar medium provides important clues on the production rate of heavier elements in stars and al ...
REVIEWS 18 years of science with the Hubble Space Telescope Julianne J. Dalcanton
... Moreover, because the HST’s view of the Universe is unperturbed by the turbulent, chaotic atmosphere, the images and spectra taken by the telescope are stable and reproducible. This stability allows for an unprecedented level of precision when measuring the brightness and structure of astrophysical ...
... Moreover, because the HST’s view of the Universe is unperturbed by the turbulent, chaotic atmosphere, the images and spectra taken by the telescope are stable and reproducible. This stability allows for an unprecedented level of precision when measuring the brightness and structure of astrophysical ...
Science and the Universe - Wayne State University Physics and
... From our location within the Galaxy, we cannot see through its far rim because the space between stars is not empty, but contains (an extremely sparse distribution of) interstellar dust or gas which absorbs visible light The interstellar gas and dust are believed to be the raw material for future fo ...
... From our location within the Galaxy, we cannot see through its far rim because the space between stars is not empty, but contains (an extremely sparse distribution of) interstellar dust or gas which absorbs visible light The interstellar gas and dust are believed to be the raw material for future fo ...
The Sun
... – By measuring distances to stars and observing how they interact with each other, scientists can determine which stars are gravitationally bound to each other. – A group of stars that are gravitationally bound to each other is called a cluster. • In an open cluster, the stars are not densely packed ...
... – By measuring distances to stars and observing how they interact with each other, scientists can determine which stars are gravitationally bound to each other. – A group of stars that are gravitationally bound to each other is called a cluster. • In an open cluster, the stars are not densely packed ...
The Milky Way and Andromeda galaxies in a constrained
... For Milky Way-mass galaxies, the most efficient feedback mechanism is believed to be that produced by stars, via the injection of energy into the interstellar medium during different phases of stellar evolution. In particular, various models for feedback from supernovae (SNe) have been included in simu ...
... For Milky Way-mass galaxies, the most efficient feedback mechanism is believed to be that produced by stars, via the injection of energy into the interstellar medium during different phases of stellar evolution. In particular, various models for feedback from supernovae (SNe) have been included in simu ...
13.5 The HR Diagram By the early 1900s, astronomers had learned
... Giants, white dwarfs, and mainsequence stars differ in more than just diameter. They also differ dramatically in their overall density. Recall that density is a body's mass divided by its volume. For a given mass, a larger body will therefore have a lower density, and so a giant star is much less d ...
... Giants, white dwarfs, and mainsequence stars differ in more than just diameter. They also differ dramatically in their overall density. Recall that density is a body's mass divided by its volume. For a given mass, a larger body will therefore have a lower density, and so a giant star is much less d ...
CH15.AST1001.S15.EDS
... • Atomic hydrogen (H) gas forms as hot gas cools, allowing electrons to join with protons. Atomic hydrogen is observed by radio telescopes in the 21 cm emission line. • Molecular clouds (H2) form next, after gas cools enough to allow atoms to combine into molecules. Molecular hydrogen is difficult ...
... • Atomic hydrogen (H) gas forms as hot gas cools, allowing electrons to join with protons. Atomic hydrogen is observed by radio telescopes in the 21 cm emission line. • Molecular clouds (H2) form next, after gas cools enough to allow atoms to combine into molecules. Molecular hydrogen is difficult ...
ph507lecnote06
... electron volt is a non- metric unit of energy that is a good size for measuring energies associated with changes of electron levels in atoms, and also for measuring energy of visible light photons. 1 eV = 1.602 x 10-19 Joules.) In purely astronomical terms, the optical portion of the spectrum is imp ...
... electron volt is a non- metric unit of energy that is a good size for measuring energies associated with changes of electron levels in atoms, and also for measuring energy of visible light photons. 1 eV = 1.602 x 10-19 Joules.) In purely astronomical terms, the optical portion of the spectrum is imp ...
E8B6_CRT_CR_MSTIPS_Final
... C. the Milky Way Galaxy is a barred-spiral galaxy which has several tentacle-like arms. D. dense regions of dust and gas block light from stars in portions of the Milky Way Galaxy. ...
... C. the Milky Way Galaxy is a barred-spiral galaxy which has several tentacle-like arms. D. dense regions of dust and gas block light from stars in portions of the Milky Way Galaxy. ...
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.