CONSTELLATION TAURUS, THE BULL The Taurus constellation
... the vicinity of Orion constellation, and the three bright stars that form Orion’s Belt point in its direction. Aldebaran lies pretty Aldebaran forms the bull's bloodshot eye, described as "glaring menacingly at the hunter Orion" close to the ecliptic and can be occulted by the Moon. Elnath – Beta Ta ...
... the vicinity of Orion constellation, and the three bright stars that form Orion’s Belt point in its direction. Aldebaran lies pretty Aldebaran forms the bull's bloodshot eye, described as "glaring menacingly at the hunter Orion" close to the ecliptic and can be occulted by the Moon. Elnath – Beta Ta ...
Section 4
... Multiple Star Systems Star systems that have two stars are called double stars or binary stars. (The prefix bi means “two.”) Those with three stars are called triple stars. The nearby star Proxima Centauri may be part of a triple star system. The other two stars in the system, Alpha Centauri A and A ...
... Multiple Star Systems Star systems that have two stars are called double stars or binary stars. (The prefix bi means “two.”) Those with three stars are called triple stars. The nearby star Proxima Centauri may be part of a triple star system. The other two stars in the system, Alpha Centauri A and A ...
Phases of Stellar Evolution
... “Low” mass stars have convective envelopes instigated by “large” H and He ionization zones. Note that μ changes dramatically in an ionization zone and they are intrinsically unstable. “High” mass stars have “shallow” ionization zones which do not perturb the structure as much. ...
... “Low” mass stars have convective envelopes instigated by “large” H and He ionization zones. Note that μ changes dramatically in an ionization zone and they are intrinsically unstable. “High” mass stars have “shallow” ionization zones which do not perturb the structure as much. ...
Slide 1
... Introduction Intermediate mass stars (1 M to 8 M) evolve through Asymptotic Giant Branch (AGB) and eventually become Planetary Nebulae (PN) ...
... Introduction Intermediate mass stars (1 M to 8 M) evolve through Asymptotic Giant Branch (AGB) and eventually become Planetary Nebulae (PN) ...
Notes (PowerPoint)
... o Asteroids (planetoids), diameters from two miles or less, up to 500 mi o Moons (sixty total in solar system) o Comet – visible only on approach to sun (tail points away from sun). Comets discovered constantly but most invisible. ...
... o Asteroids (planetoids), diameters from two miles or less, up to 500 mi o Moons (sixty total in solar system) o Comet – visible only on approach to sun (tail points away from sun). Comets discovered constantly but most invisible. ...
Analytic Models for the Mechanical Structure of the Solar Core
... In the homogeneous ZAMS Sun, 1 + ne ≡ d ln P/d ln(P/ρ) is identical to 1 + N ≡ d ln P/d ln T ≡ 1/∇ and varies from the almost adiabatic value 2.52 at z = 0 to a maximum value 5.21 at z = 0.32 (r = 0.506 of ZAMS solar radius). Where the radiative zone meets the convective core, 1 + ne shows a discont ...
... In the homogeneous ZAMS Sun, 1 + ne ≡ d ln P/d ln(P/ρ) is identical to 1 + N ≡ d ln P/d ln T ≡ 1/∇ and varies from the almost adiabatic value 2.52 at z = 0 to a maximum value 5.21 at z = 0.32 (r = 0.506 of ZAMS solar radius). Where the radiative zone meets the convective core, 1 + ne shows a discont ...
t 0 (radioactive decay)
... unstable isotopes as a way to estimate the age of stars and the Milky Way Galaxy, and thus t0. Briefly, radioactive decay is the process by which “parent” isotopes spontaneously lose energy and turn into new “daughter” isotopes. The parent isotope’s half-life defines the rate at which this decay occ ...
... unstable isotopes as a way to estimate the age of stars and the Milky Way Galaxy, and thus t0. Briefly, radioactive decay is the process by which “parent” isotopes spontaneously lose energy and turn into new “daughter” isotopes. The parent isotope’s half-life defines the rate at which this decay occ ...
Shape of a slowly rotating star measured by asteroseismology
... implies that KIC 11145123 is a terminal-age main sequence A star. It has a small convective core (r < 0.04 R), in which the fraction of hydrogen content is less than 5%. Outside this convective core, energy is transported by radiation up to the surface layers of the star. In the top few thousand kil ...
... implies that KIC 11145123 is a terminal-age main sequence A star. It has a small convective core (r < 0.04 R), in which the fraction of hydrogen content is less than 5%. Outside this convective core, energy is transported by radiation up to the surface layers of the star. In the top few thousand kil ...
00 T Tauri Stars Have Extensive Coronae?
... If there is substantial disagreement between an observational result and its expectation from established theory, astronomers tend to speak of a "problem". One of those problems wh ich bothered optical and UV astronomers during the past years is the discrepancy of the observed ratio of the Lya and H ...
... If there is substantial disagreement between an observational result and its expectation from established theory, astronomers tend to speak of a "problem". One of those problems wh ich bothered optical and UV astronomers during the past years is the discrepancy of the observed ratio of the Lya and H ...
Stellar Helium Burning in Other Universes: A
... that is not equal to twice the binding energy of helium, i.e., we require δE8 6= 2(δE4 ). This condition can be realized as long as the derivatives from equation (4) do not have specific values, i.e., we required ∂E8 /∂Mπ 6= 2 ∂E4 /∂Mπ and/or ∂E8 /∂α 6= 2 ∂E4 /∂α. Reference [14] carries out a calcul ...
... that is not equal to twice the binding energy of helium, i.e., we require δE8 6= 2(δE4 ). This condition can be realized as long as the derivatives from equation (4) do not have specific values, i.e., we required ∂E8 /∂Mπ 6= 2 ∂E4 /∂Mπ and/or ∂E8 /∂α 6= 2 ∂E4 /∂α. Reference [14] carries out a calcul ...
Neutron stars - Institut de Physique Nucleaire de Lyon
... Introduction: Neutron stars and their importance for fundamental physics Neutron-star envelopes – link between the superdense core and observations Conductivities and thermal structure of neutron star envelopes Atmospheres and thermal radiation spectra of neutron stars with magnetic fields E ...
... Introduction: Neutron stars and their importance for fundamental physics Neutron-star envelopes – link between the superdense core and observations Conductivities and thermal structure of neutron star envelopes Atmospheres and thermal radiation spectra of neutron stars with magnetic fields E ...
Neutrino hot dark matter and hydrodynamics of structure formation
... • Lynden Bell: violent relaxation, faster than collisional • Relaxation in time-dependent potential: every object (individual particle, galaxy) exchanges energy with the whole cluster • Iff phase space density becomes uniform, then Fermi-Dirac distribution • X-ray radiation helps to maintain the vir ...
... • Lynden Bell: violent relaxation, faster than collisional • Relaxation in time-dependent potential: every object (individual particle, galaxy) exchanges energy with the whole cluster • Iff phase space density becomes uniform, then Fermi-Dirac distribution • X-ray radiation helps to maintain the vir ...
X-ray Emission from Massive Stars
... Could we have been wrong about the lack of a magnetic dynamo - might massive star X-rays be similar to solar X-rays? Before we address this directly, we need to know about one very important property of massive stars (that might provide an alternate explanation for their X-rays)… ...
... Could we have been wrong about the lack of a magnetic dynamo - might massive star X-rays be similar to solar X-rays? Before we address this directly, we need to know about one very important property of massive stars (that might provide an alternate explanation for their X-rays)… ...
Magnetars origin and progenitors with enhanced rotation'
... Magnetars origin and progenitors with enhanced rotation S.B. Popov, M.E. Prokhorov (Sternberg Astronomical Institute) ...
... Magnetars origin and progenitors with enhanced rotation S.B. Popov, M.E. Prokhorov (Sternberg Astronomical Institute) ...
in the milky way - Chandra X
... velocity (i.e. speed) of a few hundred kilometers per second, completing one orbit around the center of the Milky Way about every 230 million years. In addition, the solar system is moving at about 20 kilometers per second with respect to the nearby stars. There is also a small amount of motion with ...
... velocity (i.e. speed) of a few hundred kilometers per second, completing one orbit around the center of the Milky Way about every 230 million years. In addition, the solar system is moving at about 20 kilometers per second with respect to the nearby stars. There is also a small amount of motion with ...
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.