mass and temperature of the twa 7 debris disk
... compact (<0.9 m) grains, this condition is only met for a narrow region of the size distribution. Furthermore, if the dust grains are porous, as around AU Mic (Graham et al. 2007), then no grains will have > 0:5. An alternative origin for the small grain cutoff could be stellar wind forces, since ...
... compact (<0.9 m) grains, this condition is only met for a narrow region of the size distribution. Furthermore, if the dust grains are porous, as around AU Mic (Graham et al. 2007), then no grains will have > 0:5. An alternative origin for the small grain cutoff could be stellar wind forces, since ...
Chapter 5 Theory of Stellar Evolution
... gravitationally confined within a sphere of the Jeans' length, the cloud will experience rapid core collapse until it becomes optically thick. If the outer regions contain dust, they will absorb the radiation produced by the core contraction and reradiate it in the infrared part of the spectrum. Aft ...
... gravitationally confined within a sphere of the Jeans' length, the cloud will experience rapid core collapse until it becomes optically thick. If the outer regions contain dust, they will absorb the radiation produced by the core contraction and reradiate it in the infrared part of the spectrum. Aft ...
The Formation and Evolution of the Milky Way
... complexity. We know that the Milky Way is a spiral disk galaxy, similar to many others we see in the sky. This surprisingly beautiful shape is so common among galaxies that the universe almost seems to delight in building them. The end product is especially remarkable in the light of what is believe ...
... complexity. We know that the Milky Way is a spiral disk galaxy, similar to many others we see in the sky. This surprisingly beautiful shape is so common among galaxies that the universe almost seems to delight in building them. The end product is especially remarkable in the light of what is believe ...
JUL 12 ARCHNES LIBRARIES
... astronomers began detecting incredibly bright point-like objects that looked like stars but weren't. They lay far beyond the reaches of the Milky Way, blazing from the distant past, when the universe was only a few billion years old. But while these sources were far enough away to look like pinprick ...
... astronomers began detecting incredibly bright point-like objects that looked like stars but weren't. They lay far beyond the reaches of the Milky Way, blazing from the distant past, when the universe was only a few billion years old. But while these sources were far enough away to look like pinprick ...
Extended Infrared Emission from LIRGs
... (GOALS; Armus et al. 2009) of 202 systems (181 of which are LIRGs) All systems are observed with all four Spitzer/IRS modules (5-37μm) Apply an upper limit on distance (<85 Mpc) in order for the IRS slit size to correspond to a projected distance < 1.5kpc (best case is 0.26kpc) A total of 93 galaxie ...
... (GOALS; Armus et al. 2009) of 202 systems (181 of which are LIRGs) All systems are observed with all four Spitzer/IRS modules (5-37μm) Apply an upper limit on distance (<85 Mpc) in order for the IRS slit size to correspond to a projected distance < 1.5kpc (best case is 0.26kpc) A total of 93 galaxie ...
Giant planet and brown dwarf formation
... these processes rely on completely different mechanisms or share common channels represents one of the major challenges of astronomy and remains the subject of heated debates. It is the aim of this review to summarize the latest developments in this field and to address the issue of origin by confro ...
... these processes rely on completely different mechanisms or share common channels represents one of the major challenges of astronomy and remains the subject of heated debates. It is the aim of this review to summarize the latest developments in this field and to address the issue of origin by confro ...
SAGE_prop
... Beyond the provision of light and heat, the correlation between the occurrence of sunspots and displays of spectacular aurora gave us early clues to the existence of a chain of events linking solar phenomena to a terrestrial response. Proctor in 1870 described an event where at a station in Norway “ ...
... Beyond the provision of light and heat, the correlation between the occurrence of sunspots and displays of spectacular aurora gave us early clues to the existence of a chain of events linking solar phenomena to a terrestrial response. Proctor in 1870 described an event where at a station in Norway “ ...
The destruction and survival of polycyclic aromatic hydrocarbons in
... PAH destruction process unimolecular dissociation and present a simplified scheme to estimate the location from the star at which the molecules become photo-stable. We find that soft photons with energies below ∼20 eV dissociate PAHs only up to short distances from the star (r < 1 AU); whereas disso ...
... PAH destruction process unimolecular dissociation and present a simplified scheme to estimate the location from the star at which the molecules become photo-stable. We find that soft photons with energies below ∼20 eV dissociate PAHs only up to short distances from the star (r < 1 AU); whereas disso ...
Disability accessible Draft Guide - Fermi Gamma
... The gravity from a black hole is only dangerous when you’re very close to it. Surprisingly, from a large distance, black hole gravity is no different than the gravity from a star with the same mass. The strength of gravity depends on the mass of the object and your distance from it. If the Sun were ...
... The gravity from a black hole is only dangerous when you’re very close to it. Surprisingly, from a large distance, black hole gravity is no different than the gravity from a star with the same mass. The strength of gravity depends on the mass of the object and your distance from it. If the Sun were ...
ATLASGAL -- The APEX telescope large area survey of the galaxy at
... have no bright infrared counterpart, and some of them are likely to correspond to the precursors of (high-mass) proto-stars or protoclusters. Other compact sources harbor hot cores, compact H ii regions, or young embedded clusters, thus tracing more evolved stages after massive stars have formed. As ...
... have no bright infrared counterpart, and some of them are likely to correspond to the precursors of (high-mass) proto-stars or protoclusters. Other compact sources harbor hot cores, compact H ii regions, or young embedded clusters, thus tracing more evolved stages after massive stars have formed. As ...
Slide 1
... First, a teaspoon of material from one can weigh up to a billion tons. (A large mountain) Second, an entire neutron star would be smaller than the Denver metro area. (3 times the mass of the whole sun!) Third, if you collapse a spinning thing, it speeds way up. Most neutron stars rotate between 3 an ...
... First, a teaspoon of material from one can weigh up to a billion tons. (A large mountain) Second, an entire neutron star would be smaller than the Denver metro area. (3 times the mass of the whole sun!) Third, if you collapse a spinning thing, it speeds way up. Most neutron stars rotate between 3 an ...
Astro 102 Practice Test 3
... b. it would not be rotating rapidly. c. it would be stationary. d. very little matter would be falling into it. e. there would be very few stars behind it whose light the black hole could block out. The search for black holes involves a. searching for single stars that emit large amounts of x-rays. ...
... b. it would not be rotating rapidly. c. it would be stationary. d. very little matter would be falling into it. e. there would be very few stars behind it whose light the black hole could block out. The search for black holes involves a. searching for single stars that emit large amounts of x-rays. ...
HWWS 2010 - Monash University
... Neutron star mass/radius constraints 1. Search for maximally spinning neutron stars to constrain the equation-of-state 2. Search for redshifted spectral lines from the neutrons star surface to measure the gravitational redshift 3. Compare the behaviour of thermonuclear bursts with models to test ou ...
... Neutron star mass/radius constraints 1. Search for maximally spinning neutron stars to constrain the equation-of-state 2. Search for redshifted spectral lines from the neutrons star surface to measure the gravitational redshift 3. Compare the behaviour of thermonuclear bursts with models to test ou ...
The Life of a Star
... (because it is hotter than the universe at large), at the same time it heats up and shrinks (although parts { the envelope { might well and does expand, nevertheless). 2 ...
... (because it is hotter than the universe at large), at the same time it heats up and shrinks (although parts { the envelope { might well and does expand, nevertheless). 2 ...
Star Formation: Chemistry as a Probe of Embedded Protostars
... spectrally unresolved.1 I will discuss the CO rotational lines in more detail as an example of both the opportunities and the limitations from the Herschel observations. Rotationally excited CO is ubiquitous in low-mass embedded protostars. Early observations with ground-based sub-millimeter telesco ...
... spectrally unresolved.1 I will discuss the CO rotational lines in more detail as an example of both the opportunities and the limitations from the Herschel observations. Rotationally excited CO is ubiquitous in low-mass embedded protostars. Early observations with ground-based sub-millimeter telesco ...
m82 as a galaxy: morphology and stellar content of the disk and halo
... et al. 2008, SSCs). The energy liberated from massive stars in these clusters is released as galactic superwinds, which are traced by the Hα and X-ray emitting gas as cone-shaped structures along the minor axis of the galaxy up to distances as far as 10 kpc above the galactic plane (Lehnert, Heckman ...
... et al. 2008, SSCs). The energy liberated from massive stars in these clusters is released as galactic superwinds, which are traced by the Hα and X-ray emitting gas as cone-shaped structures along the minor axis of the galaxy up to distances as far as 10 kpc above the galactic plane (Lehnert, Heckman ...
Ultra faint dwarfs: probing early cosmic star formation
... Key words: stars: formation, population II, supernovae: general - cosmology: theory - galaxies: evolution, stellar content - ...
... Key words: stars: formation, population II, supernovae: general - cosmology: theory - galaxies: evolution, stellar content - ...
A systematic study of X-ray variability in the ROSAT all
... but it does not become apparent because of the rapid change of impact parameter b with increasing scan number. In order to confirm this interpretation we simulated lightcurves where the photons for each scan were computed assuming a fixed count rate under Poisson noise. For these artificial sources ...
... but it does not become apparent because of the rapid change of impact parameter b with increasing scan number. In order to confirm this interpretation we simulated lightcurves where the photons for each scan were computed assuming a fixed count rate under Poisson noise. For these artificial sources ...
Astronomy
... Early Faint Sun • Sun is 4.6 Gyr old • Should have been much fainter when life arose – Solar evolution models predict this – Roughly 25% less solar energy flux on Earth – Would have caused a 7% temperature drop • Corresponds to ~20 degrees celsius colder ...
... Early Faint Sun • Sun is 4.6 Gyr old • Should have been much fainter when life arose – Solar evolution models predict this – Roughly 25% less solar energy flux on Earth – Would have caused a 7% temperature drop • Corresponds to ~20 degrees celsius colder ...
Confronting predictions of the galaxy stellar mass function with
... 4 to effectively convert the observed UV LF into a GSMF. To make a proper simulation prediction, we must take into account any difference between the relation between UV luminosity and the stellar mass-to-light ratio used by González et al. (2011, 2012) and that in the simulations. Fig. 2 shows the ...
... 4 to effectively convert the observed UV LF into a GSMF. To make a proper simulation prediction, we must take into account any difference between the relation between UV luminosity and the stellar mass-to-light ratio used by González et al. (2011, 2012) and that in the simulations. Fig. 2 shows the ...
12-iim fine-structure emission line and continuum images of G333.6
... 0.025 pc or 5.1 x 10 3 au. These values are smaller than that found by Hyland et al. (1980) with a slightly lower spatial resolution of 1.1 arcsec. The peak flux density is (1.5 ± 0.2) x 10 -14 W M -2 IIM -1 in the continuum, and the peak flux is (1.6 ± 0.2) x 10 -12 W M -2 in the line image, both i ...
... 0.025 pc or 5.1 x 10 3 au. These values are smaller than that found by Hyland et al. (1980) with a slightly lower spatial resolution of 1.1 arcsec. The peak flux density is (1.5 ± 0.2) x 10 -14 W M -2 IIM -1 in the continuum, and the peak flux is (1.6 ± 0.2) x 10 -12 W M -2 in the line image, both i ...
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.