Chapter 30: Stars
... Sun is about 1.50 105 kg/m3, which is about thirteen times the density of lead! A pair of dice having this density would weigh about two pounds. However, unlike lead, which is a solid, the solar interior is gaseous throughout because of its high temperature—about 1 107 K in the center. At this h ...
... Sun is about 1.50 105 kg/m3, which is about thirteen times the density of lead! A pair of dice having this density would weigh about two pounds. However, unlike lead, which is a solid, the solar interior is gaseous throughout because of its high temperature—about 1 107 K in the center. At this h ...
Neutron stars and pulsars
... Neutron star - magnetic field (II) If a spinning neutron star has a dipole magnetic field and the dipole axis and spin axis are not aligned to each other, it will emit electromagnetic radiation. As rotational energy is extracted, we can obtain an estimate of the neutron-star magnetic field from the ...
... Neutron star - magnetic field (II) If a spinning neutron star has a dipole magnetic field and the dipole axis and spin axis are not aligned to each other, it will emit electromagnetic radiation. As rotational energy is extracted, we can obtain an estimate of the neutron-star magnetic field from the ...
The Physical Nature of Cosmic Accretion of Baryons and Dark Matter
... our assumed mass profile inside the halo. For example, using an isothermal profile instead of NFW gives results that are consistent at the ∼ 10% level. Figure 2 shows the predicted values of the enclosed overdensity. Throughout this paper, we define overdensities relative to the mean matter density, ...
... our assumed mass profile inside the halo. For example, using an isothermal profile instead of NFW gives results that are consistent at the ∼ 10% level. Figure 2 shows the predicted values of the enclosed overdensity. Throughout this paper, we define overdensities relative to the mean matter density, ...
feps_jan_2007_aas - The Formation & Evolution of Planetary
... We present results from the Formation and Evolution of Planetary Systems (FEPS) Spitzer Legacy Science Program. FEPS utilizes Spitzer observations of 336 sun-like stars with ages from 3 Myr to 3 Gyr in order to construct spectral energy distributions (SEDs) from 3-160 microns, as well as obtain high ...
... We present results from the Formation and Evolution of Planetary Systems (FEPS) Spitzer Legacy Science Program. FEPS utilizes Spitzer observations of 336 sun-like stars with ages from 3 Myr to 3 Gyr in order to construct spectral energy distributions (SEDs) from 3-160 microns, as well as obtain high ...
Goal: To understand how to find the brightness of stars and what
... • So, instead of 1,2,3, we go by X1, X2,X3. • X can be anything. • For stars, X is about 2.5. • So, 5 orders of magnitude is a factor of 2.55 (which turns out to be about a factor of 100) • Some scales also have logarithmic scales for ...
... • So, instead of 1,2,3, we go by X1, X2,X3. • X can be anything. • For stars, X is about 2.5. • So, 5 orders of magnitude is a factor of 2.55 (which turns out to be about a factor of 100) • Some scales also have logarithmic scales for ...
Magnetar-driven Hypernovae
... via Blandford-Znajek mechanism if the progenitor star has strong poloidal magnetic field; + Blandford-Znajek mechanism of GRB has much lower limit on accretion rate to BH then neutrino driven one (excellent for very long GRBs); - Blandford-Znajek mechanism needs very hight magnetic flux or late expl ...
... via Blandford-Znajek mechanism if the progenitor star has strong poloidal magnetic field; + Blandford-Znajek mechanism of GRB has much lower limit on accretion rate to BH then neutrino driven one (excellent for very long GRBs); - Blandford-Znajek mechanism needs very hight magnetic flux or late expl ...
Stellar Masses
... stably. Objects with masses slightly below this limit are called brown dwarfs, and are ‘star like’ in the sense that nuclear burning of deuterium occurs in their core. Below a mass of 0.015M⊙ (roughly 16 times the mass of Jupiter) not even deuterium burning can occur, and these objects are perhaps b ...
... stably. Objects with masses slightly below this limit are called brown dwarfs, and are ‘star like’ in the sense that nuclear burning of deuterium occurs in their core. Below a mass of 0.015M⊙ (roughly 16 times the mass of Jupiter) not even deuterium burning can occur, and these objects are perhaps b ...
Magnetars origin and progenitors with enhanced rotation'
... We present population synthesis calculations of binary systems. Our goal is to estimate the number of neutron stars originated from progenitors with enhanced rotation, as such compact objects can be expected to have large magnetic fields, i.e. they can be magnetars. ...
... We present population synthesis calculations of binary systems. Our goal is to estimate the number of neutron stars originated from progenitors with enhanced rotation, as such compact objects can be expected to have large magnetic fields, i.e. they can be magnetars. ...
Progenitor and environment of the peculiar red nova V838 Mon
... The estimation of SED of the exploded companion using the light of the secondary companion lost in the eclipse. From top to bottom: progenitor, the binary system of two B3V stars (black line); exploded brighter B3V star before the outburst fitted by HD 29763 (B3V, violet line); binary combined ligh ...
... The estimation of SED of the exploded companion using the light of the secondary companion lost in the eclipse. From top to bottom: progenitor, the binary system of two B3V stars (black line); exploded brighter B3V star before the outburst fitted by HD 29763 (B3V, violet line); binary combined ligh ...
PPT - Chandra X
... 3. Fit the grouped spectrum (Chi-squared data-variance statistics, Levenberg-Marquardt optimization, kT1 [0.01-2] and kT2 [1-10] keV 4. If E(B-V) is unknown, fit again with kT, NH floating 5. Freeze kT and NH; fit for abundances 6. If two temperatures have not been found or the chi-squared statistic ...
... 3. Fit the grouped spectrum (Chi-squared data-variance statistics, Levenberg-Marquardt optimization, kT1 [0.01-2] and kT2 [1-10] keV 4. If E(B-V) is unknown, fit again with kT, NH floating 5. Freeze kT and NH; fit for abundances 6. If two temperatures have not been found or the chi-squared statistic ...
110 - Institute for Astronomy
... We explore the infrared M band (4.7 µm) spectrum of the class I protostar L1489 IRS in the Taurus Molecular Cloud. This is the highest resolution wide coverage spectrum at this wavelength of a low mass protostar observed to date (R =25,000; ∆v =12 km s−1 ). A large number of narrow absorption lines ...
... We explore the infrared M band (4.7 µm) spectrum of the class I protostar L1489 IRS in the Taurus Molecular Cloud. This is the highest resolution wide coverage spectrum at this wavelength of a low mass protostar observed to date (R =25,000; ∆v =12 km s−1 ). A large number of narrow absorption lines ...
Galaxy Structure
... satellites appear to be located near two great circles in the sky (Lynden-Bell 1976). The corona extends out to approximately 100 kpc and may account for as much as (3–6) × 1012M⊙ (Fich and Tremaine 1991). It exceeds by far the mass contained in the spiral disk and bulge region. ...
... satellites appear to be located near two great circles in the sky (Lynden-Bell 1976). The corona extends out to approximately 100 kpc and may account for as much as (3–6) × 1012M⊙ (Fich and Tremaine 1991). It exceeds by far the mass contained in the spiral disk and bulge region. ...
Estudio de Cúmulos de Galaxias en el Sloan Digital Sky Survey
... – Building Galaxy Merger Trees. ...
... – Building Galaxy Merger Trees. ...
The significant contribution of minor mergers to the cosmic star
... triggered by minor mergers in the local Universe. Splitting the star-formation budget by galaxy morphology, we find that early-type galaxies (ETGs) host ∼14% of the budget, while Sb/Sc galaxies host the bulk (∼53%) of the local star formation activity. Recent work indicates that star formation in ne ...
... triggered by minor mergers in the local Universe. Splitting the star-formation budget by galaxy morphology, we find that early-type galaxies (ETGs) host ∼14% of the budget, while Sb/Sc galaxies host the bulk (∼53%) of the local star formation activity. Recent work indicates that star formation in ne ...
the magellanic clouds newsletter - Keele University Astrophysics
... precise times of minimum light for eccentric eclipsing binaries in the Large Magellanic Cloud, needed for accurate determination of apsidal motion. Many new times of minima were derived from the photometric databases OGLE and MACHO. Several new minima were also observed. Five early-type and eccentri ...
... precise times of minimum light for eccentric eclipsing binaries in the Large Magellanic Cloud, needed for accurate determination of apsidal motion. Many new times of minima were derived from the photometric databases OGLE and MACHO. Several new minima were also observed. Five early-type and eccentri ...
Stellar Populations For many modern applications, one is not
... The above analytic solutions are only useful for guidance. To compare with observations, predictions must be made in specific bandpasses, or for specific absorption lines. This requires numerical calculations which include 1) sets of stellar isochrones, detailing the precise number of stars at any p ...
... The above analytic solutions are only useful for guidance. To compare with observations, predictions must be made in specific bandpasses, or for specific absorption lines. This requires numerical calculations which include 1) sets of stellar isochrones, detailing the precise number of stars at any p ...
Chapter 18 - Origin and Evolution of Stars Chapter Preview
... end of the life of a high-mass star that destroys the star and blows away most of its mass at supersonic velocities, several thousand kilometers per second (Figure 2). As this supersonic gas plows through the interstellar medium it smacks into giant molecular clouds, compressing them enough to trigg ...
... end of the life of a high-mass star that destroys the star and blows away most of its mass at supersonic velocities, several thousand kilometers per second (Figure 2). As this supersonic gas plows through the interstellar medium it smacks into giant molecular clouds, compressing them enough to trigg ...
Observational properties of stars
... 2. We can use this relation combined with the Eddington relation to derive a relationship between stellar luminosity, , and mass, that has the form L M 3 which is close to the relationship often used for Main Sequence stars! 3. As the star evolves and changes, this will also change the influenc ...
... 2. We can use this relation combined with the Eddington relation to derive a relationship between stellar luminosity, , and mass, that has the form L M 3 which is close to the relationship often used for Main Sequence stars! 3. As the star evolves and changes, this will also change the influenc ...
Impact on stellar properties of changing physics SAC Summer
... was originally created by Ejnar Hertzsprung and Henry Norris Russell. It shows the relationship between the star’s luminosity or absolute magnitude versus its effective temperature or spectral type. In general, stars of greater luminosity populate the top of the diagram, while stars with higher surf ...
... was originally created by Ejnar Hertzsprung and Henry Norris Russell. It shows the relationship between the star’s luminosity or absolute magnitude versus its effective temperature or spectral type. In general, stars of greater luminosity populate the top of the diagram, while stars with higher surf ...
The Local Bubble
... all,A or due to ISM are filled with hot gas, then in principle cavities in the red) are potential SXRB sources if they po-rather lar plot of the unabsorbed (foreground) 0.25between keV diffuse background charge exchange reactions solar windknowledge ions andof the 3D geometry of the ISM may be used t ...
... all,A or due to ISM are filled with hot gas, then in principle cavities in the red) are potential SXRB sources if they po-rather lar plot of the unabsorbed (foreground) 0.25between keV diffuse background charge exchange reactions solar windknowledge ions andof the 3D geometry of the ISM may be used t ...
Starburst Galaxies Under the Microscope: High
... several episodes of violent star formation, of which the last one is probably still ongoing. The resulting star clusters have been studied extensively. Radio and mid-IR observations show that the region between the two remnant nuclei (usually referred to as the overlap region) hosts spectacular obsc ...
... several episodes of violent star formation, of which the last one is probably still ongoing. The resulting star clusters have been studied extensively. Radio and mid-IR observations show that the region between the two remnant nuclei (usually referred to as the overlap region) hosts spectacular obsc ...
Effects of Mutual Transits by Extrasolar Planet
... We consider effects of mutual transits by extrasolar planet-companion systems (in a true binary or a planet-satellite system) on light curves. We show that induced changes in light curves depend strongly on a ratio between a planet-companion’s orbital velocity around their host star and a planet-com ...
... We consider effects of mutual transits by extrasolar planet-companion systems (in a true binary or a planet-satellite system) on light curves. We show that induced changes in light curves depend strongly on a ratio between a planet-companion’s orbital velocity around their host star and a planet-com ...
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.