ASTRONOMY 120
... A nova is a binary star system that suddenly brightens and then slowly fades back to normal. It is caused by an evolving star in a binary that is expanding past its Roche lobe and losing gas to a companion white dwarf. After a while, the material (primarily hydrogen) builds up on the white dwarf and ...
... A nova is a binary star system that suddenly brightens and then slowly fades back to normal. It is caused by an evolving star in a binary that is expanding past its Roche lobe and losing gas to a companion white dwarf. After a while, the material (primarily hydrogen) builds up on the white dwarf and ...
Stellar Luminosity and Mass Functions * * * * * History and
... yr (coincidentally ~ starburst time scale), but note also that for these systems tcool < tff Galaxies form quickly, at high redshifts (but evolve on a slower time scales of mergers and stellar evolution, ~ 109 yr) For clusters, tff ~ 109 - 1010 yr Clusters are still forming today ...
... yr (coincidentally ~ starburst time scale), but note also that for these systems tcool < tff Galaxies form quickly, at high redshifts (but evolve on a slower time scales of mergers and stellar evolution, ~ 109 yr) For clusters, tff ~ 109 - 1010 yr Clusters are still forming today ...
L. Moustakas
... It seems that even at~2.2, the progenitors of
massive galaxies are already in place. Are these
galaxies freshly 'assembled'? Or did that happen
much earlier, still? Why and how would 'monolithic'
collapse happen? This is a major challenge...
Even so, a lot is happening at that time. There is ...
... It seems that even at
argo and other tidal structures around the milky way
... closer to the Sun than the maximum H I asymmetries at the lines of sight where the disk warp is larger. Moreover, there is no stellar overdensity counterpart of the northern hemisphere H I warp in our data. From these facts, we conclude that both CMa and Argo overdensities are not signatures of the ...
... closer to the Sun than the maximum H I asymmetries at the lines of sight where the disk warp is larger. Moreover, there is no stellar overdensity counterpart of the northern hemisphere H I warp in our data. From these facts, we conclude that both CMa and Argo overdensities are not signatures of the ...
2014 State Test
... A18. What object is shown in the optical-light image at right? A. 47 Tucanae C. T Pyxidis B. NGC 3132 D. Vela SNR A19. Of the two stars in the center, the dimmer one is the source of the light that powers the nebula. At a surface temperature of 100,000K, what kind of light does it primarily emit? A2 ...
... A18. What object is shown in the optical-light image at right? A. 47 Tucanae C. T Pyxidis B. NGC 3132 D. Vela SNR A19. Of the two stars in the center, the dimmer one is the source of the light that powers the nebula. At a surface temperature of 100,000K, what kind of light does it primarily emit? A2 ...
Some Examples of Virtual Observatory Enabled Science What Are the Some Distinguishing
... them, in large numbers, and hopefully in a systematic fashion – This is especially important for studies of their evolution ...
... them, in large numbers, and hopefully in a systematic fashion – This is especially important for studies of their evolution ...
Problem set 1 solution
... Similar calculations for a mV = 21 star give F = 1.2 × 10−14 erg cm−2 s−1 and Fλ = 1.4 × 10−16 erg cm−2 s−1 nm−1 . (b) Photon counts We make the approximation that all photons in the V band have the energy corresponding to the central wavelength of 550nm: Eγ = hc/(550nm) = 3.6 × 10−12 erg. (Note: To ...
... Similar calculations for a mV = 21 star give F = 1.2 × 10−14 erg cm−2 s−1 and Fλ = 1.4 × 10−16 erg cm−2 s−1 nm−1 . (b) Photon counts We make the approximation that all photons in the V band have the energy corresponding to the central wavelength of 550nm: Eγ = hc/(550nm) = 3.6 × 10−12 erg. (Note: To ...
The Fomalhaut Debris Disk
... have formed) Main dust emission from ring at ~100 AU (comparable to Kuiper belt comets wrt Sun) Central cavity approximately size of Neptune's orbit. Determined the disk is a ring or torus of 280 AU diameter 20º from edgeon Ring is clumpy. Southern “lobe” has higher flux ...
... have formed) Main dust emission from ring at ~100 AU (comparable to Kuiper belt comets wrt Sun) Central cavity approximately size of Neptune's orbit. Determined the disk is a ring or torus of 280 AU diameter 20º from edgeon Ring is clumpy. Southern “lobe” has higher flux ...
Pulsars
... exclusion principle restricts position hence Heisenberg uncertainty principle allows large momentum/high pressure • Pulsating X-ray sources / X-ray pulsators - compact objects (generally neutron stars) in binary systems Accrete matter from normal star companion ...
... exclusion principle restricts position hence Heisenberg uncertainty principle allows large momentum/high pressure • Pulsating X-ray sources / X-ray pulsators - compact objects (generally neutron stars) in binary systems Accrete matter from normal star companion ...
ppt
... Removes difficulty of requiring regeneration with stellar sources which are more likely to disrupt a cloud than stabilize it ...
... Removes difficulty of requiring regeneration with stellar sources which are more likely to disrupt a cloud than stabilize it ...
Nature paper - University of Southampton
... of spin period, a result that had not been predicted and which still remains to be explained. Be/X-ray binaries (BeXs) are strong X-ray sources because their neutron stars accrete material at a relatively high rate. Their masslosing Be-type companions are fast-rotating 8M8 {18M8 mainsequence stars t ...
... of spin period, a result that had not been predicted and which still remains to be explained. Be/X-ray binaries (BeXs) are strong X-ray sources because their neutron stars accrete material at a relatively high rate. Their masslosing Be-type companions are fast-rotating 8M8 {18M8 mainsequence stars t ...
Lecture 3
... • Imagine a star with a relatively cool (4000k) atmosphere. Temperature is just a measure of the average velocity of the atoms and molecules in a gas. For a relatively cool gas there are: (1) Few atomic collisions with enough energy to knock electrons up to the 1st excited state so the majority of t ...
... • Imagine a star with a relatively cool (4000k) atmosphere. Temperature is just a measure of the average velocity of the atoms and molecules in a gas. For a relatively cool gas there are: (1) Few atomic collisions with enough energy to knock electrons up to the 1st excited state so the majority of t ...
Chandra, Spitzer & VLA Observations of Young Clusters Scott Wolk - CxC/CfA
... E. Winston (Dublin) And Many More. ...
... E. Winston (Dublin) And Many More. ...
Document
... Synchrotron emission (X-ray) by high energy electrons (~100GeV) from the neutron star’s magnetosphere (Magnetic induction: Pulsed) Synchrotron emission (X-ray) by high energy electrons (~100TeV) from the nebula around the neutron star’s magnetosphere (Accelerating shock front: Unpulsed) ...
... Synchrotron emission (X-ray) by high energy electrons (~100GeV) from the neutron star’s magnetosphere (Magnetic induction: Pulsed) Synchrotron emission (X-ray) by high energy electrons (~100TeV) from the nebula around the neutron star’s magnetosphere (Accelerating shock front: Unpulsed) ...
Summary: Star Formation Near and Far
... molecular clouds and condensations may therefore be fairly transient structures, like the structures obtained in the numerical simulations which often are more like transient fluctuations than coherent, long-lived “objects”. How is the collapse of star-forming clumps initiated? A widely accepted vi ...
... molecular clouds and condensations may therefore be fairly transient structures, like the structures obtained in the numerical simulations which often are more like transient fluctuations than coherent, long-lived “objects”. How is the collapse of star-forming clumps initiated? A widely accepted vi ...
The Life Cycle of A Star
... possible that this core will remain intact after the supernova, and be called a neutron star. However, if the original star was very massive (say 15 or more times the mass of our Sun), even the neutrons will not be able to survive the core collapse and a black hole will form! ...
... possible that this core will remain intact after the supernova, and be called a neutron star. However, if the original star was very massive (say 15 or more times the mass of our Sun), even the neutrons will not be able to survive the core collapse and a black hole will form! ...
Here
... • Stars experience rapid mass loss near the end of their “lives”, so the final mass can be much less than the initial mass. ...
... • Stars experience rapid mass loss near the end of their “lives”, so the final mass can be much less than the initial mass. ...
Chapter 25.2 - Planet Earth
... White Dwarfs White dwarfs are the remains of low-mass and medium-mass stars. They are extremely small stars with densities greater than any known material on Earth. Although some white dwarfs are no larger than Earth, the mass of such a dwarf can equal 1.4 times that of the sun. So, their densities ...
... White Dwarfs White dwarfs are the remains of low-mass and medium-mass stars. They are extremely small stars with densities greater than any known material on Earth. Although some white dwarfs are no larger than Earth, the mass of such a dwarf can equal 1.4 times that of the sun. So, their densities ...
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.