Cole Miller: Challenges in the measurements of neutron star radii
... NS masses are known up to 2 Msun. What about radii? • Radii from X-ray bursts • Radii from cooling neutron stars • Radii from X-ray light curves • The promise of gravitational waves ...
... NS masses are known up to 2 Msun. What about radii? • Radii from X-ray bursts • Radii from cooling neutron stars • Radii from X-ray light curves • The promise of gravitational waves ...
The Cosmic Near-Infrared Background: Remnant light form
... due to the mass spectrum could be large. •An accurate determination of the near-infrared background allows us to probe the formation history of early stars, which is difficult to constrain by other means. •A reasonable initial mass function, coupled with this star formation rate, does not overproduc ...
... due to the mass spectrum could be large. •An accurate determination of the near-infrared background allows us to probe the formation history of early stars, which is difficult to constrain by other means. •A reasonable initial mass function, coupled with this star formation rate, does not overproduc ...
spherical winds – spherical accretion
... Many stars are known to loose mass. The solar wind carries away about 10−14 M⊙ yr−1 of very hot plasma. This rate is insignificant. In fact, solar radiation carries away 4 × 1033 erg s −1 , which reduces solar mass by about 10−13 M⊙ yr−1 . However, very luminous, supergiant stars are losing matter a ...
... Many stars are known to loose mass. The solar wind carries away about 10−14 M⊙ yr−1 of very hot plasma. This rate is insignificant. In fact, solar radiation carries away 4 × 1033 erg s −1 , which reduces solar mass by about 10−13 M⊙ yr−1 . However, very luminous, supergiant stars are losing matter a ...
Pallavicini - IASF Milano
... • Since late-type stars suffer magnetic braking during their evolutionary history, coronal activity is a decreasing function of age through the influence of stellar rotation on the dynamo mechanism • X-ray sources in star forming regions and in young clusters provide therefore a powerful tool to ide ...
... • Since late-type stars suffer magnetic braking during their evolutionary history, coronal activity is a decreasing function of age through the influence of stellar rotation on the dynamo mechanism • X-ray sources in star forming regions and in young clusters provide therefore a powerful tool to ide ...
lecture19 - Stony Brook University
... is not a pulsar. It was discovered by Stony Brook astronomers. It is moving across the sky at 110 km/s, faster than typical for stars. The high speed is probably due to a kick given during the supernova explosion. This neutron star is seen as an X-ray source. ...
... is not a pulsar. It was discovered by Stony Brook astronomers. It is moving across the sky at 110 km/s, faster than typical for stars. The high speed is probably due to a kick given during the supernova explosion. This neutron star is seen as an X-ray source. ...
Can you write numbers in scientific notation
... What determines what object will be left behind after a star dies out? What are the properties of each of those objects? How does Einstein’s model of gravity differ from Newton’s description? Why Einstein’s description taken to be “more complete” than Newton’s? What are the effects an outside observ ...
... What determines what object will be left behind after a star dies out? What are the properties of each of those objects? How does Einstein’s model of gravity differ from Newton’s description? Why Einstein’s description taken to be “more complete” than Newton’s? What are the effects an outside observ ...
test - Scioly.org
... A) They are the central sources of energy forplanetary nebulae. B) They are very massive stars that explode as supemovae, emitting bursts of X- rays and gamma-rays. C) They are rapidly rotating black holes whose precession points their poles toward us on Jccasion. D) They are violent e,nergy sources ...
... A) They are the central sources of energy forplanetary nebulae. B) They are very massive stars that explode as supemovae, emitting bursts of X- rays and gamma-rays. C) They are rapidly rotating black holes whose precession points their poles toward us on Jccasion. D) They are violent e,nergy sources ...
Physics around Black Holes
... However, since black holes can encompass a great deal of mass in a very small area, they can form galactic nuclei, and may be the seeds for galaxies. Additionally, since black holes will accrete and “feed” on material, they can clear the area close to them of objects in unstable orbits, “selecti ...
... However, since black holes can encompass a great deal of mass in a very small area, they can form galactic nuclei, and may be the seeds for galaxies. Additionally, since black holes will accrete and “feed” on material, they can clear the area close to them of objects in unstable orbits, “selecti ...
Piper_Evans - CoolWiki
... majority of their emissions coming from their dense cloud at much longer wavelengths. Our Herschel data will deal with these longer wavelengths, finding these younger YSOs but in a different region. YSOs were classified using several methods with results as detected and corrected for reddening from ...
... majority of their emissions coming from their dense cloud at much longer wavelengths. Our Herschel data will deal with these longer wavelengths, finding these younger YSOs but in a different region. YSOs were classified using several methods with results as detected and corrected for reddening from ...
Scales of the Universe
... X-ray emission from the Sun's corona The corona is so hot that it emits X-ray radiation Rotation period: about a month The middle rotates faster than the north or south. Corona has an emission line spectrum and a continuum spectrum (dust scattering of photospheric black body light). Some of the con ...
... X-ray emission from the Sun's corona The corona is so hot that it emits X-ray radiation Rotation period: about a month The middle rotates faster than the north or south. Corona has an emission line spectrum and a continuum spectrum (dust scattering of photospheric black body light). Some of the con ...
The Origin of Oxygen Isotopic Anomalies Seen in Primitive Meteorites
... if the Sun is at the low end then any massive O star in the vicinity must not have been present 1 Myr before the Sun was born. – or need an additional 9 magnitudes of extinction ...
... if the Sun is at the low end then any massive O star in the vicinity must not have been present 1 Myr before the Sun was born. – or need an additional 9 magnitudes of extinction ...
xam2ans
... in the core of a main sequence star like the Sun? Answer: The rest mass energy of a neutron is larger than a proton plus electron. Consequently this reaction is endothermic, which means energetically unfavorable. (d) On the other hand, p+ + e → n + e does occur in a neutron star or a sufficiently ...
... in the core of a main sequence star like the Sun? Answer: The rest mass energy of a neutron is larger than a proton plus electron. Consequently this reaction is endothermic, which means energetically unfavorable. (d) On the other hand, p+ + e → n + e does occur in a neutron star or a sufficiently ...
L12-no equations
... Description of a black hole is entirely based on theory of General Relativity beyond scope of this course. But simple arguments can be illustrative: Black holes are completely collapsed objects - radius of the “star” becomes so small that the escape velocity approaches the speed of light: Escape vel ...
... Description of a black hole is entirely based on theory of General Relativity beyond scope of this course. But simple arguments can be illustrative: Black holes are completely collapsed objects - radius of the “star” becomes so small that the escape velocity approaches the speed of light: Escape vel ...
PROBLEM SET #9 SOLUTIONS AST142 1. Quasar luminosity
... is accreting at the Eddington rate, and show that these two findings are consistent with one another. ...
... is accreting at the Eddington rate, and show that these two findings are consistent with one another. ...
PH607lec10
... clear possibility and is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm. 2. Interaction. With the discovery of the Sagittarius Dwarf Elliptical Galaxy in 1994 came the discovery of a ribbon of galactic debris as the polar orbit of Sagittarius and its interaction ...
... clear possibility and is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm. 2. Interaction. With the discovery of the Sagittarius Dwarf Elliptical Galaxy in 1994 came the discovery of a ribbon of galactic debris as the polar orbit of Sagittarius and its interaction ...
AY5 Announcements
... Evolution of <8MSun Stars • For stars less than 8Mo these last slides describe the evolution pretty well. There are some differences in the details that depend on the initial main-sequence mass. • For stars that start with 4Mo, it gets hot enough in the cores to ignite start carbon fusion on ...
... Evolution of <8MSun Stars • For stars less than 8Mo these last slides describe the evolution pretty well. There are some differences in the details that depend on the initial main-sequence mass. • For stars that start with 4Mo, it gets hot enough in the cores to ignite start carbon fusion on ...
10.1 The Solar Neighborhood Barnard`s Star
... Apparent luminosity is measured using a magnitude scale, which is related to our perception. It is a logarithmic scale; a change of 5 in magnitude corresponds to a change of a factor of 100 in apparent brightness. It is also inverted – larger magnitudes are dimmer. ...
... Apparent luminosity is measured using a magnitude scale, which is related to our perception. It is a logarithmic scale; a change of 5 in magnitude corresponds to a change of a factor of 100 in apparent brightness. It is also inverted – larger magnitudes are dimmer. ...
lecture
... • Two morphologies seem to be found in the Short Period Systems • Disk-Like Morphology - Transient disk is found in the tomograms. U Sge, SW Cyg, TT Hya •Stream-Like Morphology - Dominant gas seems to be along the path of the gas stream. U CrB •What causes each of these? Why do systems switch from o ...
... • Two morphologies seem to be found in the Short Period Systems • Disk-Like Morphology - Transient disk is found in the tomograms. U Sge, SW Cyg, TT Hya •Stream-Like Morphology - Dominant gas seems to be along the path of the gas stream. U CrB •What causes each of these? Why do systems switch from o ...
ph607-15-test2ans
... (b)The criteria for convection to occur can be satisfied in two ways; either the ratio of specific heats is close to unity or the temperature gradient is very steep. The former occurs in cool layers, where the gas is partially ionized, while the latter occurs in very hot layers where the energy gene ...
... (b)The criteria for convection to occur can be satisfied in two ways; either the ratio of specific heats is close to unity or the temperature gradient is very steep. The former occurs in cool layers, where the gas is partially ionized, while the latter occurs in very hot layers where the energy gene ...
Binary Stars/Star Clusters
... Assumption: all stars of a given cluster formed from same Nebula ∴ All stars of a single cluster are (1) the same distance from Earth & (2) the same age ...
... Assumption: all stars of a given cluster formed from same Nebula ∴ All stars of a single cluster are (1) the same distance from Earth & (2) the same age ...
Chemical Evolution of the Galaxy and its satellites
... • The SFR is the star formation rate (how many solar masses go into stars per unit time) • The IMF is the initial stellar mass function describing the distribution of stars as a function of stellar mass ...
... • The SFR is the star formation rate (how many solar masses go into stars per unit time) • The IMF is the initial stellar mass function describing the distribution of stars as a function of stellar mass ...
Chapter 7 Neutron Stars - Ira-Inaf
... which tends to zero as the system becomes completely nonrelativistic. The second term behaves similarly, while the third depends on the gravitational potential and is thus a general relativistic effect. (Now the stellar radius of about 10 km is 1/400th that of the white dwarf we previously discussed ...
... which tends to zero as the system becomes completely nonrelativistic. The second term behaves similarly, while the third depends on the gravitational potential and is thus a general relativistic effect. (Now the stellar radius of about 10 km is 1/400th that of the white dwarf we previously discussed ...
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.