Explosive sources of the highest energy radiation
... location consistent with that of Cyg X-3 and at the same time as a radio outburst was detected. The association of the gamma-ray flaring source was confirmed through the detection of the 4.8-hour orbital period in the LAT light curve (Abdo et al. 2009). The gamma-ray light curve of the source flux i ...
... location consistent with that of Cyg X-3 and at the same time as a radio outburst was detected. The association of the gamma-ray flaring source was confirmed through the detection of the 4.8-hour orbital period in the LAT light curve (Abdo et al. 2009). The gamma-ray light curve of the source flux i ...
Sample pages 1 PDF
... It is the relatively small- to medium-sized stars that will undergo evolution to the planetary nebula stage. The diagram below reveals the basics of the changes the star will suffer and the predicted track across the diagram to an end point. If one starts with a Sun-like star with a temperature of 6 ...
... It is the relatively small- to medium-sized stars that will undergo evolution to the planetary nebula stage. The diagram below reveals the basics of the changes the star will suffer and the predicted track across the diagram to an end point. If one starts with a Sun-like star with a temperature of 6 ...
Star formation in a galactic outflow
... However, an external source of stellar ionization should result in an ionization parameter (defined as the ratio between ionizing photon flux and gas density; when divided by the speed of light it is the adimensional ionization parameter U) much lower than typically observed in star-forming galaxie ...
... However, an external source of stellar ionization should result in an ionization parameter (defined as the ratio between ionizing photon flux and gas density; when divided by the speed of light it is the adimensional ionization parameter U) much lower than typically observed in star-forming galaxie ...
The Circumstellar Environments of Young Stars at AU Scales
... disks (Kenyon and Hartmann, 1987; Chiang and Goldreich, 1997)]. In this review, we will refer to these classes of models as “classical,” to be distinguished from models with a modified inner disk structure that have recently emerged in part to explain the NIR interferometer measurements. The outline ...
... disks (Kenyon and Hartmann, 1987; Chiang and Goldreich, 1997)]. In this review, we will refer to these classes of models as “classical,” to be distinguished from models with a modified inner disk structure that have recently emerged in part to explain the NIR interferometer measurements. The outline ...
The observed distribution of spectroscopic binaries from the Anglo
... Mamajek & Hillenbrand (2008) due to the sparse activity–age data for older dwarf stars. The activity values have been drawn from the studies of Henry et al. (1996), Tinney et al. (2002), Jenkins et al. (2006), and Jenkins et al. (2011), yet even considering these four works, there are still three st ...
... Mamajek & Hillenbrand (2008) due to the sparse activity–age data for older dwarf stars. The activity values have been drawn from the studies of Henry et al. (1996), Tinney et al. (2002), Jenkins et al. (2006), and Jenkins et al. (2011), yet even considering these four works, there are still three st ...
UGA Physics Colloquium - Academics
... 3-D radiation-hydrodynamic numerical simulations of the formation of HII regions in accretion flows are now possible The dense, rotating, accretion flows required to form massive stars quickly become gravitationally unstable High-resolution simulations (Peters et al. 2010a) show that when accr ...
... 3-D radiation-hydrodynamic numerical simulations of the formation of HII regions in accretion flows are now possible The dense, rotating, accretion flows required to form massive stars quickly become gravitationally unstable High-resolution simulations (Peters et al. 2010a) show that when accr ...
Chapter 1
... The constellation of Orion is one of the most discernable patterns in the northern hemisphere, and has acted as an important beacon for generations throughout history. Orion stands central in many mythological tales. One of my personal favorites describes the figure of Orion, the hunter, standing by ...
... The constellation of Orion is one of the most discernable patterns in the northern hemisphere, and has acted as an important beacon for generations throughout history. Orion stands central in many mythological tales. One of my personal favorites describes the figure of Orion, the hunter, standing by ...
On the interpretation of stellar disc observations in terms of diameters
... this layer contribute only a small fraction of the observed intensity and observed flux. If the star were observed in different spectral features with successively increasing strength at about the same wavelength, an observer who cannot spatially resolve the disc and tries to interpret lunar-occulta ...
... this layer contribute only a small fraction of the observed intensity and observed flux. If the star were observed in different spectral features with successively increasing strength at about the same wavelength, an observer who cannot spatially resolve the disc and tries to interpret lunar-occulta ...
Chapter 1 Telescopes 1.1 Lenses
... the diameter of the objective of a telescope, the greater the number of stars that can be seen. Planets and other astronomical objects in the solar system are magnified using a telescope (unlike stars which are point objects and are seen through telescopes as point images no matter how large the mag ...
... the diameter of the objective of a telescope, the greater the number of stars that can be seen. Planets and other astronomical objects in the solar system are magnified using a telescope (unlike stars which are point objects and are seen through telescopes as point images no matter how large the mag ...
Winds from accretion disks driven by the radiation and
... loss rate between these two types of winds can be several orders of magnitude for low disk luminosities but vanishes for high disk luminosities. Winds which conserve angular velocity have much higher velocities than angular momentum conserving winds. Fixing the wind geometry stabilizes winds which a ...
... loss rate between these two types of winds can be several orders of magnitude for low disk luminosities but vanishes for high disk luminosities. Winds which conserve angular velocity have much higher velocities than angular momentum conserving winds. Fixing the wind geometry stabilizes winds which a ...
radiation and matter interaction in strong magnetic field of accreting
... the accreted matter is released in the form of X-rays coming from the area on the surface of the NS close to the magnetic poles where the matter is stopped and heated to very high temperatures (107 − 108 K). If the accreting NS is highly magnetized and the magnetic axis is misaligned with respect to ...
... the accreted matter is released in the form of X-rays coming from the area on the surface of the NS close to the magnetic poles where the matter is stopped and heated to very high temperatures (107 − 108 K). If the accreting NS is highly magnetized and the magnetic axis is misaligned with respect to ...
X-ray activity cycle on the active ultra
... the photospheric and chromospheric activity cycle are related. Baliunas et al. (1995) employed the same technique of studying stellar activity to also monitor the solar activity-cycle in integrated light and showed that the so-called S-index of the Sun varies between 0.16 and 0.22 between its activi ...
... the photospheric and chromospheric activity cycle are related. Baliunas et al. (1995) employed the same technique of studying stellar activity to also monitor the solar activity-cycle in integrated light and showed that the so-called S-index of the Sun varies between 0.16 and 0.22 between its activi ...
Downloadable Full Text
... 1.1. Properties of the Regulus System Regulus (α Leo; HD 87901) was recently discovered to be a spectroscopic binary which has a likely white dwarf companion of mass Mwd 0.3 M and an orbital period of Porb 40.11 d (Gies et al. 2008; hereafter “the inner binary system”). Regulus itself has an in ...
... 1.1. Properties of the Regulus System Regulus (α Leo; HD 87901) was recently discovered to be a spectroscopic binary which has a likely white dwarf companion of mass Mwd 0.3 M and an orbital period of Porb 40.11 d (Gies et al. 2008; hereafter “the inner binary system”). Regulus itself has an in ...
Epsilon Aurigae: a rare stellar eclipse - Project VS
... This data was also confirmed with the direct observation of the current eclipse from an international team lead by Brian Kloppenborg at the University of Denver. The new images show that this is the case: a geometrically thin, dark, dense, but partially transparent cloud can be seen passing in fron ...
... This data was also confirmed with the direct observation of the current eclipse from an international team lead by Brian Kloppenborg at the University of Denver. The new images show that this is the case: a geometrically thin, dark, dense, but partially transparent cloud can be seen passing in fron ...
three-body dynamics with gravitational wave emission
... that can be produced with roughly solar metallicity stellar evolution (Fryer & Kalogera 2001). The ULXs are thought to be powered by black holes because many are variable, but they cannot be powered by supermassive black holes or they would have sunk to the center of their host galaxies because of d ...
... that can be produced with roughly solar metallicity stellar evolution (Fryer & Kalogera 2001). The ULXs are thought to be powered by black holes because many are variable, but they cannot be powered by supermassive black holes or they would have sunk to the center of their host galaxies because of d ...
Non-conservative mass transfers in Algols
... (2001). In this study, 18 of these Algols, showing only parabolic O−C diagrams, were selected in order to investigate their orbital period changes and apply the revised model of non-conservative mass transfer. The SD parameter in Table 1 is a crude probability indicator for binaries having an SD nat ...
... (2001). In this study, 18 of these Algols, showing only parabolic O−C diagrams, were selected in order to investigate their orbital period changes and apply the revised model of non-conservative mass transfer. The SD parameter in Table 1 is a crude probability indicator for binaries having an SD nat ...
Theoretical Predictions for Mass Loss Rates: Rotation & Pulsation
... What sets the Sun’s mass loss? • Coronal heating must be ultimately responsible. ...
... What sets the Sun’s mass loss? • Coronal heating must be ultimately responsible. ...
STELLAR MASSES AND STAR FORMATION RATES OF LENSED DUSTY STAR-FORMING... FROM THE SPT SURVEY
... Note. — We adopt the source redshift for SPT0538-50 obtained with ATCA CO(1-0) spectroscopy by Aravena et al. (2013). The lens parameters derived from GALFIT (e.g., Sérsic index, effective radius) are held fixed during the de-blending process. For the ones with multiple components, we list the Sérs ...
... Note. — We adopt the source redshift for SPT0538-50 obtained with ATCA CO(1-0) spectroscopy by Aravena et al. (2013). The lens parameters derived from GALFIT (e.g., Sérsic index, effective radius) are held fixed during the de-blending process. For the ones with multiple components, we list the Sérs ...
A STRONGLY MAGNETIZED PULSAR WITHIN THE GRASP OF THE MILKY... SUPERMASSIVE BLACK HOLE Rea ,
... 1046 Ṗ /P 3 erg s−1 = 4.9 × 1033 erg s−1 , and a characteristic age τc ∼ P /(2Ṗ ) ∼ 9 kyr. Radio observations performed with Parkes and GBT detected the magnetar radio emission (Eatough et al. 2013) with the flux and pulse profile variability typical of radio magnetars. The DM derived from Parkes ...
... 1046 Ṗ /P 3 erg s−1 = 4.9 × 1033 erg s−1 , and a characteristic age τc ∼ P /(2Ṗ ) ∼ 9 kyr. Radio observations performed with Parkes and GBT detected the magnetar radio emission (Eatough et al. 2013) with the flux and pulse profile variability typical of radio magnetars. The DM derived from Parkes ...
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.