J: Chapter 4: Stars and Galaxies
... How do scientists determine distance to stars from the solar system that Earth is part of? One way is to measure its parallax—the apparent shift in the position of an object when viewed from two different positions. Extend your arm and look at your thumb first with your left eye closed and then with ...
... How do scientists determine distance to stars from the solar system that Earth is part of? One way is to measure its parallax—the apparent shift in the position of an object when viewed from two different positions. Extend your arm and look at your thumb first with your left eye closed and then with ...
High Resolution Spectroscopy of Stars with GMTNIRS
... Discovered the infra-red in 1800 “By placing one thermometer within the [solar] red rays, separated by a prism, and another beyond them, he found the temperature of the outside thermometer raised by more than that of the inside.” Humphrey Davy to Davies Giddy 3 July 1800 ...
... Discovered the infra-red in 1800 “By placing one thermometer within the [solar] red rays, separated by a prism, and another beyond them, he found the temperature of the outside thermometer raised by more than that of the inside.” Humphrey Davy to Davies Giddy 3 July 1800 ...
Lesson 1 The Sun and Other Stars
... magnitude. Apparent magnitude depends on how much light a star gives off and how far away it is from Earth. ...
... magnitude. Apparent magnitude depends on how much light a star gives off and how far away it is from Earth. ...
Lecture notes 17: Active Galaxies
... Also radio quiet quasars have been discovered, these are also known as as QSO’s (quasi-stellar objects). In total 10% of quasars are radio-loud, 90% radio-quiet. There are now 10 000 quasars known with red-shifts z = 0.06−5.8. Most quasars are at z > 0.3, i.e at distances greater than 1000 Mpc. Red- ...
... Also radio quiet quasars have been discovered, these are also known as as QSO’s (quasi-stellar objects). In total 10% of quasars are radio-loud, 90% radio-quiet. There are now 10 000 quasars known with red-shifts z = 0.06−5.8. Most quasars are at z > 0.3, i.e at distances greater than 1000 Mpc. Red- ...
Star Clock
... This clock is calibrated for Alaska Daylight Time, and works best on clear nights. It can be tested in the Planetarium as a project for young students. ...
... This clock is calibrated for Alaska Daylight Time, and works best on clear nights. It can be tested in the Planetarium as a project for young students. ...
Neutron stars: compact objects with relativistic
... compactness and curvature assert that relativistic gravity is indispensable for the description of neutron stars. One may thus hope to employ neutron stars for seeking deviations from general relativity or as test beds to constrain alternative or modified models of gravity [25, 27, 28]. The discover ...
... compactness and curvature assert that relativistic gravity is indispensable for the description of neutron stars. One may thus hope to employ neutron stars for seeking deviations from general relativity or as test beds to constrain alternative or modified models of gravity [25, 27, 28]. The discover ...
Linking Asteroids and Meteorites through Reflectance
... What is a galaxy? • Is a massive, gravitationally bound system consisting of stars, gas and dust, and dark matter. Galaxies can contain between ten million and a trillion stars • Dark matter is matter that does not emit or reflect enough radiation to be seen, but whose gravitation effects can be fe ...
... What is a galaxy? • Is a massive, gravitationally bound system consisting of stars, gas and dust, and dark matter. Galaxies can contain between ten million and a trillion stars • Dark matter is matter that does not emit or reflect enough radiation to be seen, but whose gravitation effects can be fe ...
Geoscience
... New Earth is formed near what feature? For those of you who like to split hairs, the age of the atoms are the same. We speak of the time when the molten material hardened into stone. a. Subduction zone c. Lithosphere b. Mid-ocean ridge d. Epicenters Plates tend to move about the Earth. Why do they ...
... New Earth is formed near what feature? For those of you who like to split hairs, the age of the atoms are the same. We speak of the time when the molten material hardened into stone. a. Subduction zone c. Lithosphere b. Mid-ocean ridge d. Epicenters Plates tend to move about the Earth. Why do they ...
Distance Measurement in Astronomy
... The direction of Centauri is measured against the background of the distant stars at the two points P1 and P2. The angle 2A is measured and so the parallax (angle A) can be found. If you know the angle A and the radius of the Earth’s orbit (R) you can find the distance of the star (D). Stars that ...
... The direction of Centauri is measured against the background of the distant stars at the two points P1 and P2. The angle 2A is measured and so the parallax (angle A) can be found. If you know the angle A and the radius of the Earth’s orbit (R) you can find the distance of the star (D). Stars that ...
Solutions for Midterm
... Answer as many of the following questions as you can. Full credit for this part is 90 points; any additional points you earn above this will be added as 30% bonus points (for a maximum of ...
... Answer as many of the following questions as you can. Full credit for this part is 90 points; any additional points you earn above this will be added as 30% bonus points (for a maximum of ...
Lecture 26
... center and also centered in the dense star cluster • About 1000 solar luminosities • Many astronomers believed the radio emissions was coming from hot gas in orbit around a supermassive black hole ...
... center and also centered in the dense star cluster • About 1000 solar luminosities • Many astronomers believed the radio emissions was coming from hot gas in orbit around a supermassive black hole ...
Searching for the Secrets of Massive Star Birth
... increasing the probability of one or more being massive? What can multiplicity reveal about protostar / core collisions and competitive accretion? What role does cluster dynamics play in determining the IMF? Under what circumstances are massive stars ejected? Do low mass stars form first, with star ...
... increasing the probability of one or more being massive? What can multiplicity reveal about protostar / core collisions and competitive accretion? What role does cluster dynamics play in determining the IMF? Under what circumstances are massive stars ejected? Do low mass stars form first, with star ...
Section9 - University of Chicago
... Simulations of reionization suggest that it occurs in a clumpy fashion – with individual zones of ionized hydrogen first forming around the first stars and quasars, and then growing and connecting until most of the universe is reionized – by about z=6 as quasar data suggest. ...
... Simulations of reionization suggest that it occurs in a clumpy fashion – with individual zones of ionized hydrogen first forming around the first stars and quasars, and then growing and connecting until most of the universe is reionized – by about z=6 as quasar data suggest. ...
NASSP Class Test – 2008 April 7th Section A
... and hence explain why the spectral type sequence OBAFGKM is principally a temperature sequence. ...
... and hence explain why the spectral type sequence OBAFGKM is principally a temperature sequence. ...
Downloadable Full Text
... The UFD Reticulum II (Ret II) was recently discovered with Dark Energy Survey data12,13 and confirmed to be one of the most metal-poor galaxies known14. On 1-4 Oct 2015, we obtained high-resolution spectra of the nine brightest member stars in Ret II (see Table 1, Extended Data Figure 1). The abunda ...
... The UFD Reticulum II (Ret II) was recently discovered with Dark Energy Survey data12,13 and confirmed to be one of the most metal-poor galaxies known14. On 1-4 Oct 2015, we obtained high-resolution spectra of the nine brightest member stars in Ret II (see Table 1, Extended Data Figure 1). The abunda ...
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.