Heating and Cooling of Neutron Star Crusts
... A theoretical crust model was developed in this work to follow the evolution of the quiescent luminosity of a transiently accreting neutron star, and its results were compared with observations of two transient neutron stars: KS 1731-260 and MXB 1659-298. The comparison shows that the calculations f ...
... A theoretical crust model was developed in this work to follow the evolution of the quiescent luminosity of a transiently accreting neutron star, and its results were compared with observations of two transient neutron stars: KS 1731-260 and MXB 1659-298. The comparison shows that the calculations f ...
Formation Process of the Circumstellar Disk
... We believe that stars are born with a circumstellar disk. The formation of the circumstellar disk is coupled with “the angular momentum problem” that is a serious problem in the star formation process, and the dynamics of disks may determine the mass accretion rate onto the protostar that determines ...
... We believe that stars are born with a circumstellar disk. The formation of the circumstellar disk is coupled with “the angular momentum problem” that is a serious problem in the star formation process, and the dynamics of disks may determine the mass accretion rate onto the protostar that determines ...
space telescope imaging spectrograph survey of far
... and an absolute wavelength calibration compared with using the Chandra or XMM-Newton grating spectrometers to observe permitted transitions of the same ion stages in the kilovolt X-ray region. Fe xii 1242, 1349 (T 2 106 K) and Fe xxi 1354 (107 K) are well known from solar studies and have bee ...
... and an absolute wavelength calibration compared with using the Chandra or XMM-Newton grating spectrometers to observe permitted transitions of the same ion stages in the kilovolt X-ray region. Fe xii 1242, 1349 (T 2 106 K) and Fe xxi 1354 (107 K) are well known from solar studies and have bee ...
Unraveling the Helix Nebula: Its Structure and Knots
... inner-disk. This interpretation is strengthened by its explanation of the complex radial velocity pattern described by radio and optical observations. There is an outer structure called the outermost-ring whose form suggests that it has the same orientation as the outerring. The northeast portion of ...
... inner-disk. This interpretation is strengthened by its explanation of the complex radial velocity pattern described by radio and optical observations. There is an outer structure called the outermost-ring whose form suggests that it has the same orientation as the outerring. The northeast portion of ...
Deneb - Emmi
... Deneb, which means tail in Arabic, is the 19th brightest star in the universe, and one of the most well known stars in our very own Milky Way. ...
... Deneb, which means tail in Arabic, is the 19th brightest star in the universe, and one of the most well known stars in our very own Milky Way. ...
Applications of Photospheric Spot Temperature Models ... Stellar Angular Momentum Evolution
... 1.1 The Magnetic Disk-Locking Model and the Angular Momentum Conundrum 1.2 Observed Rotation Period Distributions of CTTS and WTTS ...
... 1.1 The Magnetic Disk-Locking Model and the Angular Momentum Conundrum 1.2 Observed Rotation Period Distributions of CTTS and WTTS ...
The impact of surface temperature inhomogeneities on quiescent
... appropriate for the accretion- and nuclear-powered pulsations observed in accreting systems in outburst. However, this calculation has not been performed specifically for hydrogen atmosphere models (which experience greater limb darkening) at temperatures relevant to quiescent NS low-mass X-ray bina ...
... appropriate for the accretion- and nuclear-powered pulsations observed in accreting systems in outburst. However, this calculation has not been performed specifically for hydrogen atmosphere models (which experience greater limb darkening) at temperatures relevant to quiescent NS low-mass X-ray bina ...
Planet formation and migration
... At the time of the writing of this review, the tenth anniversary of the discovery of the first extrasolar planet around a solar–type star is being celebrated. When this detection was announced, it came as a shock, not because an extrasolar planet was at last found around a star like our Sun — nobody ...
... At the time of the writing of this review, the tenth anniversary of the discovery of the first extrasolar planet around a solar–type star is being celebrated. When this detection was announced, it came as a shock, not because an extrasolar planet was at last found around a star like our Sun — nobody ...
Introduction_to_pulsar_astronomy
... Most pulsars show significant departures from simple, uniformly slowing rotation. The two main departures are: Glitches. This corresponds to starquakes, caused by a sudden shrinkage in the star’s size, with corresponding spin up. Timing noise. The origin of this phenomenon is unknown. The younger th ...
... Most pulsars show significant departures from simple, uniformly slowing rotation. The two main departures are: Glitches. This corresponds to starquakes, caused by a sudden shrinkage in the star’s size, with corresponding spin up. Timing noise. The origin of this phenomenon is unknown. The younger th ...
9 The Clearing of Protoplanetary Disks and of the Protosolar Nebula
... and the slope of the SED at these wavelengths can be used to infer the size distribution of grains in the outer disk (Testi et al. 2003). This technique has shown that several disks around low- and intermediate-mass stars formed millimeter and up to cm-sized particles already in the first Myr of the ...
... and the slope of the SED at these wavelengths can be used to infer the size distribution of grains in the outer disk (Testi et al. 2003). This technique has shown that several disks around low- and intermediate-mass stars formed millimeter and up to cm-sized particles already in the first Myr of the ...
Herschel far-infrared observations of the Carina Nebula complex⋆
... (HST) Hα imaging survey. The driving sources of many of these jets were recently revealed and analyzed by Ohlendorf et al. (2012a). Povich et al. (2011) published a catalog of 1439 YSO candidates (PCYC catalog) based on mid-infrared excess emission detected in the Spitzer data. A recent deep wide-fi ...
... (HST) Hα imaging survey. The driving sources of many of these jets were recently revealed and analyzed by Ohlendorf et al. (2012a). Povich et al. (2011) published a catalog of 1439 YSO candidates (PCYC catalog) based on mid-infrared excess emission detected in the Spitzer data. A recent deep wide-fi ...
Where stars form: inside-out growth and coherent star formation from
... spatially resolved spectroscopy. Because this spectrograph is slitless, it provides a spectrum for every object in its field of view. This means that for every object its field of view and wavelength coverage, the grism can be used to create a high spatial resolution emission line map. The 3D-HST le ...
... spatially resolved spectroscopy. Because this spectrograph is slitless, it provides a spectrum for every object in its field of view. This means that for every object its field of view and wavelength coverage, the grism can be used to create a high spatial resolution emission line map. The 3D-HST le ...
The Current Status of Galaxy Formation
... The inferred value of the mass-to-light ratio M/L is similar to that observed for L∗ galaxies. This is a success for theory: dissipation provides a key ingredient in understanding the stellar masses of galaxies, at least for the “typical” galaxy. The characteristic galactic mass is understood by the ...
... The inferred value of the mass-to-light ratio M/L is similar to that observed for L∗ galaxies. This is a success for theory: dissipation provides a key ingredient in understanding the stellar masses of galaxies, at least for the “typical” galaxy. The characteristic galactic mass is understood by the ...
Chapter 9 Early stages of evolution and the main sequence phase
... The process of star formation constitutes one of the main problems of modern astrophysics. Compared to our understanding of what happens after stars have formed out of the interstellar medium – that is, stellar evolution – star formation is a very ill-understood problem. No predictive theory of star ...
... The process of star formation constitutes one of the main problems of modern astrophysics. Compared to our understanding of what happens after stars have formed out of the interstellar medium – that is, stellar evolution – star formation is a very ill-understood problem. No predictive theory of star ...
Final Stages of Stellar Evolution - supernovae and the synthesis of
... Final Stages of Stellar Evolution supernovae and the synthesis of heavy nuclei ...
... Final Stages of Stellar Evolution supernovae and the synthesis of heavy nuclei ...
the au microscopii debris disk: multiwavelength imaging and modeling
... physical characteristics are removed with spatially resolved images of the thermal and scattered light; however, the faintness of the dust and often large dynamic range between the star and disk present significant obstacles to their acquisition. Resolved images are both rare and valuable. Images at ...
... physical characteristics are removed with spatially resolved images of the thermal and scattered light; however, the faintness of the dust and often large dynamic range between the star and disk present significant obstacles to their acquisition. Resolved images are both rare and valuable. Images at ...
as a PDF
... Ori stars, may be the progenitors to stars similar to β Pictoris (Grinin et al. 1996). Here we take the approach that, as in the cTTSs, the forbidden lines can be used as a diagnostic for the presence of a disk. Observations of forbidden lines, such as [OI]λλ6300/6364 and [SII]λλ6716/6731, however, ...
... Ori stars, may be the progenitors to stars similar to β Pictoris (Grinin et al. 1996). Here we take the approach that, as in the cTTSs, the forbidden lines can be used as a diagnostic for the presence of a disk. Observations of forbidden lines, such as [OI]λλ6300/6364 and [SII]λλ6716/6731, however, ...
Equations of state and structure of neutron stars
... First theoretical idea of neutron stars comes from Baade and Zwicky [13], being based on the analysis of supernova explosions. They stated that supernova explosion could be transition a from star to a neutron star. They also predicted that neutron stars consist of closely packed neutrons in the obje ...
... First theoretical idea of neutron stars comes from Baade and Zwicky [13], being based on the analysis of supernova explosions. They stated that supernova explosion could be transition a from star to a neutron star. They also predicted that neutron stars consist of closely packed neutrons in the obje ...
Evolution of stars
... What causes the outward pressure that balances the inward pull of gravity in a star? a. The outward flow of energy. b. The opacity of the gas. c. The temperature of the gas d. The density of the gas e. c and d The free-fall contraction of a molecular cloud a. can be initiated by shock waves from sup ...
... What causes the outward pressure that balances the inward pull of gravity in a star? a. The outward flow of energy. b. The opacity of the gas. c. The temperature of the gas d. The density of the gas e. c and d The free-fall contraction of a molecular cloud a. can be initiated by shock waves from sup ...
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.