Stars - CBSD.org
... • Hipparchus decided that all the brightest stars in the night sky were “first order magnitude” stars. • As they got dimmer, he classified them as “second magnitude,” “third magnitude,” and so on… • He got up to magnitude 6, after which stars are too dim to be seen without a telescope. • So, a star’ ...
... • Hipparchus decided that all the brightest stars in the night sky were “first order magnitude” stars. • As they got dimmer, he classified them as “second magnitude,” “third magnitude,” and so on… • He got up to magnitude 6, after which stars are too dim to be seen without a telescope. • So, a star’ ...
Disks around low-mass stars in extreme environments
... → requires observations with high resolution & sensitivity ...
... → requires observations with high resolution & sensitivity ...
JCMT Debris Disks Survey - Physics and Astronomy
... • Flux list for nearby star photospheric fluxes where no disk is detected ...
... • Flux list for nearby star photospheric fluxes where no disk is detected ...
Inti didn`t form in the X wind (and neither did most CAIs)
... and both dumped mass onto star and fed the decretion flow. Inferred surface densities are those of planetesimals when they could accrete into planetary cores = densities of planetesimals when they grew large enough to dynamically decouple from the gas. Steady state presumed reached within ~ 105 year ...
... and both dumped mass onto star and fed the decretion flow. Inferred surface densities are those of planetesimals when they could accrete into planetary cores = densities of planetesimals when they grew large enough to dynamically decouple from the gas. Steady state presumed reached within ~ 105 year ...
Observations of gravitational microlensing events with OSIRIS
... camera - reaching point sources of about 19 mag - is good enough for any event spotted by OGLE or MOA (Microlensing Observations in Astrophysics), but it cannot readily be applied to the dense star fields close to the Galactic Centre. From an image that was taken with OSIRIS at Right Ascension 18h 2 ...
... camera - reaching point sources of about 19 mag - is good enough for any event spotted by OGLE or MOA (Microlensing Observations in Astrophysics), but it cannot readily be applied to the dense star fields close to the Galactic Centre. From an image that was taken with OSIRIS at Right Ascension 18h 2 ...
Stellar Evolution
... • A core with remaining mass of 1.4 to 3 M, composed of tightly packed neutrons. • These tiny stars are much smaller than planet Earth -- in fact, they are about the diameter of a large city (~20 km). • One cubic centimeter (like a sugar cube) of a neutron star, would have a mass of about 1011 kg! ...
... • A core with remaining mass of 1.4 to 3 M, composed of tightly packed neutrons. • These tiny stars are much smaller than planet Earth -- in fact, they are about the diameter of a large city (~20 km). • One cubic centimeter (like a sugar cube) of a neutron star, would have a mass of about 1011 kg! ...
Document
... INTRODUCTIONu The hot, diffuse, x-ray emitting interstellar medium of the Milky Way Galaxy appears almost featureless, unless it is observed in the soft x-ray band. In 1995, complex structures, visible only between 0.1 and 2.0keV, were revealed by the ROSAT all-sky survey. The XMM-Newton observatory ...
... INTRODUCTIONu The hot, diffuse, x-ray emitting interstellar medium of the Milky Way Galaxy appears almost featureless, unless it is observed in the soft x-ray band. In 1995, complex structures, visible only between 0.1 and 2.0keV, were revealed by the ROSAT all-sky survey. The XMM-Newton observatory ...
PowerPoint Presentation - Center for Gravitational Wave Physics
... • Arnett (1982) (also see Pinto & Eastman 2000) showed that the peak in the lightcurve occurs when the radiation diffusion time through the envelope equals the time since explosion, giving ...
... • Arnett (1982) (also see Pinto & Eastman 2000) showed that the peak in the lightcurve occurs when the radiation diffusion time through the envelope equals the time since explosion, giving ...
–1– 1. Stellar Evolution For Massive Stars 1.1. The Importance of
... dependence on mass, mass loss becomes very important for high mass stars. If high mass 0Z stars really do have very weak winds, they will not be very effective at polluting the ISM with nuclear processed materials, as most of their mass will end up in black holes. Solar metallicity high mass stars w ...
... dependence on mass, mass loss becomes very important for high mass stars. If high mass 0Z stars really do have very weak winds, they will not be very effective at polluting the ISM with nuclear processed materials, as most of their mass will end up in black holes. Solar metallicity high mass stars w ...
solar.gmu.edu
... 1. Why are quasars unusual? How did astronomers discover that they are extraordinarily distant and luminous? 2. What evidence showed a link between quasars and galaxies? 3. How are Seyfert galaxies and radio galaxies related to quasars? 4. How can material ejected from quasars appear to travel faste ...
... 1. Why are quasars unusual? How did astronomers discover that they are extraordinarily distant and luminous? 2. What evidence showed a link between quasars and galaxies? 3. How are Seyfert galaxies and radio galaxies related to quasars? 4. How can material ejected from quasars appear to travel faste ...
Lecture 13 Hydrogen Burning on the Main Sequence and Homology
... on the main sequence. 1. The central temperature of more massive main sequence stars tends to be hotter (unless R increases more than linearly with M on the main sequence and it doesn’t) 2. That the actual radius of the star will depend on the form of the energy generation. Until nuclear energy ge ...
... on the main sequence. 1. The central temperature of more massive main sequence stars tends to be hotter (unless R increases more than linearly with M on the main sequence and it doesn’t) 2. That the actual radius of the star will depend on the form of the energy generation. Until nuclear energy ge ...
The Formation of Stars and Solar Systems
... formed stars. The hottest of these heat the surrounding molecular gas, break up its molecules, and drive the gas away. • As the celestial smog of gas and dust clears, the previously hidden young stars become visible, and the molecular cloud and its star-birthing capability cease to exist. In 1995 th ...
... formed stars. The hottest of these heat the surrounding molecular gas, break up its molecules, and drive the gas away. • As the celestial smog of gas and dust clears, the previously hidden young stars become visible, and the molecular cloud and its star-birthing capability cease to exist. In 1995 th ...
Document
... Note: P- relations of the type P=K are called polytropic equations of state. We saw that this is exact for degenerate matter (e.g., inside a white dwarf ) and a good approximation for some normal stars. Now back to the fate of the evolving stars: During the contraction of a star, nuclear reacti ...
... Note: P- relations of the type P=K are called polytropic equations of state. We saw that this is exact for degenerate matter (e.g., inside a white dwarf ) and a good approximation for some normal stars. Now back to the fate of the evolving stars: During the contraction of a star, nuclear reacti ...
Summary of Astronomy
... at the University of Alaska Fairbanks. Akasofu has studied the aurora since 1957, and he thinks other planets' auroras could be used to detect life elsewhere in the universe. The idea was inspired by the discovery of three planets circling a sun that's much like ours, though a bit bigger. The star, ...
... at the University of Alaska Fairbanks. Akasofu has studied the aurora since 1957, and he thinks other planets' auroras could be used to detect life elsewhere in the universe. The idea was inspired by the discovery of three planets circling a sun that's much like ours, though a bit bigger. The star, ...
General Relativity Einstein`s Theory of Gravity Paul Woodward
... region ever seen in space. The so-called Lynx arc is 1 million times brighter than the well-known Orion Nebula, a nearby prototypical star-birth region visible with small telescopes. The newly identified super-cluster contains a million blue-white stars that are twice as hot as similar stars in our ...
... region ever seen in space. The so-called Lynx arc is 1 million times brighter than the well-known Orion Nebula, a nearby prototypical star-birth region visible with small telescopes. The newly identified super-cluster contains a million blue-white stars that are twice as hot as similar stars in our ...
Properties of Stars Measuring Stars Apparent Magnitude, m Range
... the dark lines are due to absorption by chemical elements in the photosphere the bright lines are due to emission in the outer layers ...
... the dark lines are due to absorption by chemical elements in the photosphere the bright lines are due to emission in the outer layers ...
Lyman-α observations of astrospheres
... FX1.34±0.18 , for X-ray surface fluxes FX < 106 erg cm−2 s−1 . While the fit looks good considering the roughly factor of two uncertainties in the mass-loss rate measurements and the varying X-ray fluxs that were measured at different times, there is no accepted explanation for this power-law relati ...
... FX1.34±0.18 , for X-ray surface fluxes FX < 106 erg cm−2 s−1 . While the fit looks good considering the roughly factor of two uncertainties in the mass-loss rate measurements and the varying X-ray fluxs that were measured at different times, there is no accepted explanation for this power-law relati ...
Magnetized Gravitational Collapse & Star Formation
... Singular Isothermal Toroids AD leads to gravomagneto catastrophe, whereby center formally tries to reach infinite density in finite time – seems to be nonlinear attractor state with ρ~1/r², B~1/r, Ω~1/r. If we approximate the pivotal state as static, it satisfies ...
... Singular Isothermal Toroids AD leads to gravomagneto catastrophe, whereby center formally tries to reach infinite density in finite time – seems to be nonlinear attractor state with ρ~1/r², B~1/r, Ω~1/r. If we approximate the pivotal state as static, it satisfies ...
Compton scattering in strong gravity
... In the case of an accretion disk surrounding a black hole the disk produces a thermal spectrum with typical energy of few kiloelectronvolts or less (depending on the mass of the black hole). The lower energy photons emitted from the disk surface are scattered to higher energies by relativistic elect ...
... In the case of an accretion disk surrounding a black hole the disk produces a thermal spectrum with typical energy of few kiloelectronvolts or less (depending on the mass of the black hole). The lower energy photons emitted from the disk surface are scattered to higher energies by relativistic elect ...
11.6 Protoplanetary disks
... - Vertical temperature gradients with cooler disk mid-plane. - Disk temperature increase with increasing central stellar mass. ...
... - Vertical temperature gradients with cooler disk mid-plane. - Disk temperature increase with increasing central stellar mass. ...
- EPJ Web of Conferences
... and metallicity of a background eclipsing binary system to vary. 4. To determine the statistical significance of a χ2 difference between two fits we conduct Monte Carlo simulations which allow for the possibility of systematic errors that are not accounted for by our instrumental model (see Hartman ...
... and metallicity of a background eclipsing binary system to vary. 4. To determine the statistical significance of a χ2 difference between two fits we conduct Monte Carlo simulations which allow for the possibility of systematic errors that are not accounted for by our instrumental model (see Hartman ...
Notes HERE
... Bursts of X rays have been observed near the center of our Galaxy. A typical one appears at right, as imaged in the X-ray spectrum. Copyright © 2010 Pearson Education, Inc. ...
... Bursts of X rays have been observed near the center of our Galaxy. A typical one appears at right, as imaged in the X-ray spectrum. Copyright © 2010 Pearson Education, Inc. ...
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source, thought to be a black hole, in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 6977229999999999999♠2.3×10−23 Wm−2 Hz−1 (7003230000000000000♠2.3×103 Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole and it remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 7004440000000000000♠44 km.Cygnus X-1 belongs to a high-mass X-ray binary system about 7019574266339685654♠6070 ly from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 7001400000000000000♠40 solar masses. The majority of the star's mass was shed, most likely as a stellar wind. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole.Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1975, with Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case that there was indeed a black hole in the system. This hypothesis has not been confirmed due to a lack of direct observation but has generally been accepted from indirect evidence.