Today`s Powerpoint
... Also, squeezing of clouds initiates collapse within them => star formation. Bright young massive stars live and die in spiral arms. Emission nebulae mostly in spiral arms. So arms always contain same types of objects, but individual objects come and go. ...
... Also, squeezing of clouds initiates collapse within them => star formation. Bright young massive stars live and die in spiral arms. Emission nebulae mostly in spiral arms. So arms always contain same types of objects, but individual objects come and go. ...
lecture2 - X-Ray
... Accretion in close binaries Accretion is the most powerful source of energy realized in Nature, which can give a huge energy output. When matter fall down onto the surface of a neutron star up to 10% of mc2 can be released. ...
... Accretion in close binaries Accretion is the most powerful source of energy realized in Nature, which can give a huge energy output. When matter fall down onto the surface of a neutron star up to 10% of mc2 can be released. ...
Structure of Neutron Stars - Relativistic Astrophysics Department
... Kv – observed semi-amplitude of line of sight velocity of the normal star (in km/s), P – orbital period (in days), e – orbital eccentricity, i – orbital inclination (the angle between the prbital plane and line of sight). ...
... Kv – observed semi-amplitude of line of sight velocity of the normal star (in km/s), P – orbital period (in days), e – orbital eccentricity, i – orbital inclination (the angle between the prbital plane and line of sight). ...
Celestial Distances
... Henrietta Levitt (1908): systematic search found many Cepheid variables including hundreds in the Magellanic Clouds The Magellanic Clouds are nearby “dwarf” galaxies All stars in the Magellanic Clouds are roughly same distance away -- like observing the Moon from Earth ...
... Henrietta Levitt (1908): systematic search found many Cepheid variables including hundreds in the Magellanic Clouds The Magellanic Clouds are nearby “dwarf” galaxies All stars in the Magellanic Clouds are roughly same distance away -- like observing the Moon from Earth ...
Physics 306
... o Coronal gas – million degrees K (very hot), low density; thought to form by supernovae exploding. *makes up about 5% of interstellar mass Wavelength Observations: o 21 cm observations – can map the distribution of neutral hydrogen (HI) not ionized hydrogen b/c it lacks an electron and can’t emit ...
... o Coronal gas – million degrees K (very hot), low density; thought to form by supernovae exploding. *makes up about 5% of interstellar mass Wavelength Observations: o 21 cm observations – can map the distribution of neutral hydrogen (HI) not ionized hydrogen b/c it lacks an electron and can’t emit ...
2014 State Test
... A. Lagrange exchange C. Wien barrier mass loss B. Tidal stream transfer D. Roche lobe overflow B10. The process mentioned in question B9 is responsible for which variety of variable star? A. S Doradus C. Mira B. Recurrent novae D. T Tauri B11. While a star is on the main sequence, the vast majority ...
... A. Lagrange exchange C. Wien barrier mass loss B. Tidal stream transfer D. Roche lobe overflow B10. The process mentioned in question B9 is responsible for which variety of variable star? A. S Doradus C. Mira B. Recurrent novae D. T Tauri B11. While a star is on the main sequence, the vast majority ...
Poster 49 | PDF (852 kB)
... formation?” and “How important is dynamical evolution for cluster mass functions?”. In recent years, methane imaging has emerged as a powerful tool for identifying T dwarf candidates in very young clusters, where T dwarfs are at their brightest and have not yet been subject to possible dynamical eje ...
... formation?” and “How important is dynamical evolution for cluster mass functions?”. In recent years, methane imaging has emerged as a powerful tool for identifying T dwarf candidates in very young clusters, where T dwarfs are at their brightest and have not yet been subject to possible dynamical eje ...
Outline - Picnic Point High School
... The Universe began with a singularity in space-time. After the initial explosion, the Universe started to expand, cool and condense, forming matter. As part of this ongoing process the Sun and the Solar System were formed over 4x109 years ago from a gas cloud which resulted from a supernova explosio ...
... The Universe began with a singularity in space-time. After the initial explosion, the Universe started to expand, cool and condense, forming matter. As part of this ongoing process the Sun and the Solar System were formed over 4x109 years ago from a gas cloud which resulted from a supernova explosio ...
5. Star Formation and the Interstellar Medium in the Milky Way
... interstellar chemistry. Nonetheless, the great bulk of the relevant data come from heterodyne observations of rotational spectra at mm and sub-mm wavelengths. The high sensitivity, angular resolution, and mapping speed of the LMT will enable detailed investigations of the chemistry of interstellar m ...
... interstellar chemistry. Nonetheless, the great bulk of the relevant data come from heterodyne observations of rotational spectra at mm and sub-mm wavelengths. The high sensitivity, angular resolution, and mapping speed of the LMT will enable detailed investigations of the chemistry of interstellar m ...
Mass loss of massive stars near the Eddington luminosity by core
... observations may infer that some WR stars explode with much larger radii than those predicted by the current stellar evolution theory. One of the characteristics of massive stars shortly before the explosion is their huge neutrino luminosities. Neutrinos are constantly emitted from the stellar core ...
... observations may infer that some WR stars explode with much larger radii than those predicted by the current stellar evolution theory. One of the characteristics of massive stars shortly before the explosion is their huge neutrino luminosities. Neutrinos are constantly emitted from the stellar core ...
The physics of white dwarfs
... for reasons that are not yet fully understood. In ordinary stars, differences among the spectra are primarily due to differences in effective surface temperatures Teff (and, to a lesser extent, in surface gravities), rather than to large intrinsic differences in abundances. Near Tef(« 10 000 K, norm ...
... for reasons that are not yet fully understood. In ordinary stars, differences among the spectra are primarily due to differences in effective surface temperatures Teff (and, to a lesser extent, in surface gravities), rather than to large intrinsic differences in abundances. Near Tef(« 10 000 K, norm ...
AS1001:Extra-Galactic Astronomy Stars and Gas in Galaxies
... Stars and Gas in Galaxies • Stars are born from gas in high-density regions. • Compressing gas (e.g. in collisions, or spiral arms) triggers gravitational collapse to form stars. – Ellipticals: very little gas ...
... Stars and Gas in Galaxies • Stars are born from gas in high-density regions. • Compressing gas (e.g. in collisions, or spiral arms) triggers gravitational collapse to form stars. – Ellipticals: very little gas ...
black_holes
... A star shines because its center is so hot and dense that hydrogen nuclei fuse together, creating tremendous energy. It lives for millions or billions of years while the inward pull from its own gravity is balanced by the outward pressure from nuclear fusion. Its life ends when the nuclear fuel has ...
... A star shines because its center is so hot and dense that hydrogen nuclei fuse together, creating tremendous energy. It lives for millions or billions of years while the inward pull from its own gravity is balanced by the outward pressure from nuclear fusion. Its life ends when the nuclear fuel has ...
Slide 1
... •Ellipticals have lots of globular clusters (about twice that of disk galaxies) •these fall into two groups based on color •color determined by metallicity, with more metal-rich GCs (redder) possibly the result of galaxy mergers •Ellipticals have much less cool, atomic gas than spiral galaxies •< 1 ...
... •Ellipticals have lots of globular clusters (about twice that of disk galaxies) •these fall into two groups based on color •color determined by metallicity, with more metal-rich GCs (redder) possibly the result of galaxy mergers •Ellipticals have much less cool, atomic gas than spiral galaxies •< 1 ...
Photometric analysis of the globular cluster NGC5466
... between 3.1 and 3.3. The globular cluster NGC5466 results to be at a distance of 14.7 Kpc and to have metallicity Z=0.0004. The very low value of metallicity reflects some characteristics of the HR-diagram, such as the remarkable length of the horizontal branch and the marked slope of the giant bran ...
... between 3.1 and 3.3. The globular cluster NGC5466 results to be at a distance of 14.7 Kpc and to have metallicity Z=0.0004. The very low value of metallicity reflects some characteristics of the HR-diagram, such as the remarkable length of the horizontal branch and the marked slope of the giant bran ...
Expected Coalescence Rate of NS/NS Binaries for Laser Beam
... the star formation rate is proportional to the available mass of gas as, R*(t) ~ e-at present work: the star formation history is reconstructed from observations: ages of 552 stars derived from chromospheric activity index (Rocha-Tinto et al., 2000) enhanced periods of star formation at 1 Gyr, 2 ...
... the star formation rate is proportional to the available mass of gas as, R*(t) ~ e-at present work: the star formation history is reconstructed from observations: ages of 552 stars derived from chromospheric activity index (Rocha-Tinto et al., 2000) enhanced periods of star formation at 1 Gyr, 2 ...
Red Supergiants, Luminous Blue Variables and Wolf
... der Hucht 1988) are too weak for producing this kind of evolution for stars in the mass range between 12 and 25-30 M (at least for standard non-rotating models). However the uncertainties are large, actually, the determinations of the mass loss during the RSG phase is still more difficult than in t ...
... der Hucht 1988) are too weak for producing this kind of evolution for stars in the mass range between 12 and 25-30 M (at least for standard non-rotating models). However the uncertainties are large, actually, the determinations of the mass loss during the RSG phase is still more difficult than in t ...
Astrophysics E1. This question is about stars.
... ● therefore in the distant past the universe must have been a very small/hot/dense point-like object; or ● Doppler shift of spectral lines; ● indicates galaxies moving away so in the past they were close to each other; ...
... ● therefore in the distant past the universe must have been a very small/hot/dense point-like object; or ● Doppler shift of spectral lines; ● indicates galaxies moving away so in the past they were close to each other; ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.