WORD - Astrophysics
... elements like Mg or Ca that have been empirically calibrated to relate to the metallicity (or iron abundance) of the star in which they are measured, e.g., the Ca II triplet absorption lines at 8500A (Figure 4.2). This is merely considered a metallicity indicator- it gives a rough estimate of the to ...
... elements like Mg or Ca that have been empirically calibrated to relate to the metallicity (or iron abundance) of the star in which they are measured, e.g., the Ca II triplet absorption lines at 8500A (Figure 4.2). This is merely considered a metallicity indicator- it gives a rough estimate of the to ...
GRB jets and their interaction with the progenitor star
... smaller for more massive and large stars ...
... smaller for more massive and large stars ...
POSTERS SESSION I: Atmospheres of Massive Stars
... Many classes of these stars are also seen, via photometric or line-profile variability, to pulsate radially or nonradially. It has been suspected for some time that these oscillations can induce periodic modulations in the surrounding stellar wind and produce observational signatures in line profile ...
... Many classes of these stars are also seen, via photometric or line-profile variability, to pulsate radially or nonradially. It has been suspected for some time that these oscillations can induce periodic modulations in the surrounding stellar wind and produce observational signatures in line profile ...
The Relationship Between a Star`s Brightness and its Distance
... • Using parallax to find distances has limits. • Because we can only accurately measure a parallax angle to about 0.01 arcseconds, parallax is only accurate to about 100 pc or roughly 300 LY. • Since the galaxy is 30,000 to 40,000 pc wide, parallax can only find the distances to stars that are in ou ...
... • Using parallax to find distances has limits. • Because we can only accurately measure a parallax angle to about 0.01 arcseconds, parallax is only accurate to about 100 pc or roughly 300 LY. • Since the galaxy is 30,000 to 40,000 pc wide, parallax can only find the distances to stars that are in ou ...
Stellar Magnitudes & Distances
... • Using parallax to find distances has limits. • Because we can only accurately measure a parallax angle to about 0.01 arcseconds, parallax is only accurate to about 100 pc or roughly 300 LY. • Since the galaxy is 30,000 to 40,000 pc wide, parallax can only find the distances to stars that are in ou ...
... • Using parallax to find distances has limits. • Because we can only accurately measure a parallax angle to about 0.01 arcseconds, parallax is only accurate to about 100 pc or roughly 300 LY. • Since the galaxy is 30,000 to 40,000 pc wide, parallax can only find the distances to stars that are in ou ...
AST 207 Final Exam 14 December 2009
... a. (2 pts.) Explain why the sun moves with respect to the stars. b. (2 pts.) Explain why the planets sometimes moves east to west with respect to the stars, which is opposite the way the sun moves. c. (2 pts.) Explain why Mars moves east to west with respect to the horizon. d. (3 pts.) Copernicus’s ...
... a. (2 pts.) Explain why the sun moves with respect to the stars. b. (2 pts.) Explain why the planets sometimes moves east to west with respect to the stars, which is opposite the way the sun moves. c. (2 pts.) Explain why Mars moves east to west with respect to the horizon. d. (3 pts.) Copernicus’s ...
MIXED CHEMISTRY
... flight (TOF) mass spectrometry. A notable feature is the appearance of … fullerenes such as C50 , C60 , and C70 . There is also evidence in these mass spectra for the ejection of small dehydrogenated polycyclic ...
... flight (TOF) mass spectrometry. A notable feature is the appearance of … fullerenes such as C50 , C60 , and C70 . There is also evidence in these mass spectra for the ejection of small dehydrogenated polycyclic ...
Discovering X-ray Bright Neutron Stars for Current and Next-Generation
... – No binary companions – No supernova remnant ...
... – No binary companions – No supernova remnant ...
molecular observations of H CO , 13CO, HCN how to determine
... also much easier to excite high dipole mom. mol. can show analytically : Tx varies as (α nm nH2 Cul )1/2 è Tx depends only on mol. abundance ! (not A-coef.) Note : 13CO vs CO -- lower intensity does not mean τ < 1 ! ...
... also much easier to excite high dipole mom. mol. can show analytically : Tx varies as (α nm nH2 Cul )1/2 è Tx depends only on mol. abundance ! (not A-coef.) Note : 13CO vs CO -- lower intensity does not mean τ < 1 ! ...
Stellar Dynamics
... of statistical overdensity among the less massive particles passing through the wake. These gravitating collective modes of many small masses interact with each other, enhancing their lifetimes and producing a larger effective statistical condensation behind M through which particles of mass m move ...
... of statistical overdensity among the less massive particles passing through the wake. These gravitating collective modes of many small masses interact with each other, enhancing their lifetimes and producing a larger effective statistical condensation behind M through which particles of mass m move ...
Primary-centric World-View proposes a Fractal Architecture
... • Figure 6. The map above is a slice of the Universe which shows the Sculptor Wall. • The map is a plot 7400 bright galaxies in the vicinity of the Sculptor Wall. • Top of the map is 800Mly from the bottom where Milky Way is situated. • Red line shows the Sculptor Wall. • Nearest part of the wall (P ...
... • Figure 6. The map above is a slice of the Universe which shows the Sculptor Wall. • The map is a plot 7400 bright galaxies in the vicinity of the Sculptor Wall. • Top of the map is 800Mly from the bottom where Milky Way is situated. • Red line shows the Sculptor Wall. • Nearest part of the wall (P ...
Spiral Arms - Harry Kroto
... The spiral arms are regions where stars' and gas clouds' orbits bunch up closer to one another and the region becomes overdense. Stars go in and move out of the pattern, but the pattern persists and moves at its own rate. Since the region is overdense when gas clouds enter it they are compressed and ...
... The spiral arms are regions where stars' and gas clouds' orbits bunch up closer to one another and the region becomes overdense. Stars go in and move out of the pattern, but the pattern persists and moves at its own rate. Since the region is overdense when gas clouds enter it they are compressed and ...
PHY104 - Introduction to Astrophysics
... see each one hit the screen individually. The location of each photon as it hits the screen is seemingly random; one photon arrives at a given location and a moment later another photon arrives somewhere else. Over time, however, as we watch the photons arrive one-by-one, we find more photons are hi ...
... see each one hit the screen individually. The location of each photon as it hits the screen is seemingly random; one photon arrives at a given location and a moment later another photon arrives somewhere else. Over time, however, as we watch the photons arrive one-by-one, we find more photons are hi ...
"The Probability and Effects of an Asteroid Impact with Earth"
... Tex = temperature derived using the Boltzmann equation to establish a match to the observed energy level populations of atoms. Tion = temperature derived using the Saha equation to establish a match to the observed ionization states of atoms. Tkin = temperature as inferred from the Maxwell-Boltzmann ...
... Tex = temperature derived using the Boltzmann equation to establish a match to the observed energy level populations of atoms. Tion = temperature derived using the Saha equation to establish a match to the observed ionization states of atoms. Tkin = temperature as inferred from the Maxwell-Boltzmann ...
doc - StealthSkater
... The article states that the study of the paths for the parts of Sagittarius gives different parameters for the dark matter distribution. Maybe the "parts" refer to the 4 globular clusters of stars belonging to Sagittarius. In any case, a highly-refined study of the structure of the star stream left ...
... The article states that the study of the paths for the parts of Sagittarius gives different parameters for the dark matter distribution. Maybe the "parts" refer to the 4 globular clusters of stars belonging to Sagittarius. In any case, a highly-refined study of the structure of the star stream left ...
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.