Supermassive black holes - University of Texas Astronomy Home
... We don’t know which massive stars do which! Tendency to think that more massive stars are more prone to making black holes, but the rotation of the star, the presence of a binary companion, and other factors may influence the outcome. ...
... We don’t know which massive stars do which! Tendency to think that more massive stars are more prone to making black holes, but the rotation of the star, the presence of a binary companion, and other factors may influence the outcome. ...
Spin-Driven Changes in Neutron Star Magnetic Fields
... expected in a spinning-down neutron star whenever spin-down expels enough flux from the stellar core into the equatorial regions of the lower crust. Although this sort of event should occur less than once a millenium for a Vela-like pulsar, it should happen every few decades in a 104 year old pulsar ...
... expected in a spinning-down neutron star whenever spin-down expels enough flux from the stellar core into the equatorial regions of the lower crust. Although this sort of event should occur less than once a millenium for a Vela-like pulsar, it should happen every few decades in a 104 year old pulsar ...
The discovery based on GLIMPSE data of a protostar driving a
... Lada (1987) developed a widely used classification scheme for YSOs primarily based on their spectral energy distributions (SEDs) and the spectral index at the infrared. With an evolutionary sequence from early to late type, YSOs were classified into Class I to III (Lada 1987). Later on, an earlier e ...
... Lada (1987) developed a widely used classification scheme for YSOs primarily based on their spectral energy distributions (SEDs) and the spectral index at the infrared. With an evolutionary sequence from early to late type, YSOs were classified into Class I to III (Lada 1987). Later on, an earlier e ...
How is Light Made?
... as photons. These photons carry a certain energy which is related to its frequency. This energy is equal to Planck’s constant (h) multiplied by the frequency of the photon. By substituting “nu” with the equation in the previous slide, we can get the equivalent equation in terms of wavelength. Planck ...
... as photons. These photons carry a certain energy which is related to its frequency. This energy is equal to Planck’s constant (h) multiplied by the frequency of the photon. By substituting “nu” with the equation in the previous slide, we can get the equivalent equation in terms of wavelength. Planck ...
Dark matter, neutron stars and strange quark matter
... typically the LSP neutralinos of SUSY models, are the most frequently considered. WIMPs from the galactic halo can be accreted onto compact massive objects [2], such as neutron stars (NS) [3, 4] and white dwarfs [5, 6]. Our focus here will be on the consequences of neutralino WIMP capture by NS. Acc ...
... typically the LSP neutralinos of SUSY models, are the most frequently considered. WIMPs from the galactic halo can be accreted onto compact massive objects [2], such as neutron stars (NS) [3, 4] and white dwarfs [5, 6]. Our focus here will be on the consequences of neutralino WIMP capture by NS. Acc ...
THE YELLOW SUPERGIANT PROGENITOR OF THE TYPE II
... Telescope, the Telescopio Nazionale Galileo, as well as a number of other telescopes available to the collaboration. The results of the complete follow-up campaign will be published in a forthcoming paper (M. Ergon et al. 2011, in preparation). Here we present data obtained during the first ∼50 days ...
... Telescope, the Telescopio Nazionale Galileo, as well as a number of other telescopes available to the collaboration. The results of the complete follow-up campaign will be published in a forthcoming paper (M. Ergon et al. 2011, in preparation). Here we present data obtained during the first ∼50 days ...
A STEP Expected Yield of Planets
... - planetary distribution as a function of stellar type (unknown from G-stars biased RV surveys) - distribution of “Very Hot Jupiter” planets, undiscovered by RV up to date • 2 subsets for planetary distribution to reproduce ...
... - planetary distribution as a function of stellar type (unknown from G-stars biased RV surveys) - distribution of “Very Hot Jupiter” planets, undiscovered by RV up to date • 2 subsets for planetary distribution to reproduce ...
Folie 1
... The difficult problem of calibration at low energies It is dangerous to use theoretical spectra of astrophysical objects to calibrate satellite instruments. E.g. hot white dwarfs with pure hydrogen atmosphere spectra have been used to „recalibrate“ the ROSAT PSPC, EUVE Short Wave ...
... The difficult problem of calibration at low energies It is dangerous to use theoretical spectra of astrophysical objects to calibrate satellite instruments. E.g. hot white dwarfs with pure hydrogen atmosphere spectra have been used to „recalibrate“ the ROSAT PSPC, EUVE Short Wave ...
ASTR1102-002 Potentially useful facts and mathematical relations
... What “astronomer’s technique” does a police officer usually use in order to measure whether or not you are speeding? a. The officer measures your car’s “proper motion.” b. The officer relies on a “Doppler shift” measurement. c. The officer measures the apparent brightness of your headlights. d. The ...
... What “astronomer’s technique” does a police officer usually use in order to measure whether or not you are speeding? a. The officer measures your car’s “proper motion.” b. The officer relies on a “Doppler shift” measurement. c. The officer measures the apparent brightness of your headlights. d. The ...
Chapter15 (with interactive links)
... The stars in globular clusters in the halo have some heavy elements, so at least one prior generation of stars must have existed. Halo objects were formed before interstellar gas was all concentrated into the disk. Later star formation has been concentrated in the disk. ...
... The stars in globular clusters in the halo have some heavy elements, so at least one prior generation of stars must have existed. Halo objects were formed before interstellar gas was all concentrated into the disk. Later star formation has been concentrated in the disk. ...
Eclipsing Binary Stars as Astrophysical Laboratories
... The Stefan-Boltzmann law tells us that the luminosity of the star is the product of a bunch of constants times the radius of the star squared, times the surface temperature raised to the fourth power. If your measurements of the star tell you the luminosity and the temperature, then you can calculat ...
... The Stefan-Boltzmann law tells us that the luminosity of the star is the product of a bunch of constants times the radius of the star squared, times the surface temperature raised to the fourth power. If your measurements of the star tell you the luminosity and the temperature, then you can calculat ...
Document
... This is piecewise, time-weighted summation in an AgeFlux table for stars Ψ(k,j) is the birth rate function of stars of type k in the ...
... This is piecewise, time-weighted summation in an AgeFlux table for stars Ψ(k,j) is the birth rate function of stars of type k in the ...
Variable Blue Stragglers in M67
... study. I report here the progress and some results drawn from this project. ...
... study. I report here the progress and some results drawn from this project. ...
Part 2 - Aryabhat
... degrees Fahrenheit (6,000 to 8,000 Kelvin) -- that has ceased hydrogen fusion and is now in the process of converting its core helium into carbon. This process as led to its current size, 65 times that of the Sun. If we were to replace our Sun with Canopus, it would almost envelope Mercury. Canopus ...
... degrees Fahrenheit (6,000 to 8,000 Kelvin) -- that has ceased hydrogen fusion and is now in the process of converting its core helium into carbon. This process as led to its current size, 65 times that of the Sun. If we were to replace our Sun with Canopus, it would almost envelope Mercury. Canopus ...
S1-4-03 - Celestial Navigation
... Part A: Star Trails Begin by showing students a star trails photograph of how stars move across the night sky in the northern hemisphere. Try to draw out more in-depth reasoning for the circular pattern and the star in the middle, explaining that the picture is of star trails due to the earth's rota ...
... Part A: Star Trails Begin by showing students a star trails photograph of how stars move across the night sky in the northern hemisphere. Try to draw out more in-depth reasoning for the circular pattern and the star in the middle, explaining that the picture is of star trails due to the earth's rota ...
February 2004
... After a cloudy, rainy week, there was not much hope of seeing anything, but in the event, the clouds cleared for an hour or so, and the five of us who came (Brian, Jean, Wayne Michael and Johan Smit) saw some fine sights. Mars is still in the evening sky in the north west, perhaps almost forgotten a ...
... After a cloudy, rainy week, there was not much hope of seeing anything, but in the event, the clouds cleared for an hour or so, and the five of us who came (Brian, Jean, Wayne Michael and Johan Smit) saw some fine sights. Mars is still in the evening sky in the north west, perhaps almost forgotten a ...
Part1
... Low mass galaxies have less heavy elements relative to their mass: There is a strong relationship between stellar mass and heavy element abundance (gas phase & stellar) spanning many orders of magnitude. ...
... Low mass galaxies have less heavy elements relative to their mass: There is a strong relationship between stellar mass and heavy element abundance (gas phase & stellar) spanning many orders of magnitude. ...
The surface composition of Beta Pictoris
... stars with equatorial velocities of 125 km s−1 or less, and accreting at a rate of 10−13 M yr−1 , rotationally induced meridional circulation has no significant influence on the evolution of surface abundances, during the accretion episode itself.’ The true equatorial velocity of β Pic is probably ...
... stars with equatorial velocities of 125 km s−1 or less, and accreting at a rate of 10−13 M yr−1 , rotationally induced meridional circulation has no significant influence on the evolution of surface abundances, during the accretion episode itself.’ The true equatorial velocity of β Pic is probably ...
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.