Catalogs of Hot White Dwarfs in the Milky Way from GALEX`s
... phases, in which they shed much of their mass. The ejected material enriches the interstellar medium (ISM) with newly synthesized nuclear products (mainly He, C, N, and possibly O), to different extents, depending on the initial stellar mass and exact evolutionary path (e.g. Marigo 2001, Karakas 201 ...
... phases, in which they shed much of their mass. The ejected material enriches the interstellar medium (ISM) with newly synthesized nuclear products (mainly He, C, N, and possibly O), to different extents, depending on the initial stellar mass and exact evolutionary path (e.g. Marigo 2001, Karakas 201 ...
Determination of accurate stellar radial
... Abstract. Wavelength measurements in stellar spectra cannot readily be interpreted as true stellar motion on the sub-km s−1 ...
... Abstract. Wavelength measurements in stellar spectra cannot readily be interpreted as true stellar motion on the sub-km s−1 ...
A Walk through the Southern Sky: A Guide to Stars and
... been and will continue to be modified with each generation. This book applies to people living in the Southern Hemisphere, but it is also of value to those living slightly north as well as south of the equator. Relax and enjoy yourself as you travel across the sky. ...
... been and will continue to be modified with each generation. This book applies to people living in the Southern Hemisphere, but it is also of value to those living slightly north as well as south of the equator. Relax and enjoy yourself as you travel across the sky. ...
Astronomy Astrophysics Kuiper belts around nearby stars &
... Results. A total of 10 detections with at least 3σ significance were made, out of which five (HD 95086, HD 131835, HD 161868, HD 170773, and HD 207129) have previously never been detected at submillimetre wavelengths. Three additional sources are marginally detected with >2.5σ significance. The best ...
... Results. A total of 10 detections with at least 3σ significance were made, out of which five (HD 95086, HD 131835, HD 161868, HD 170773, and HD 207129) have previously never been detected at submillimetre wavelengths. Three additional sources are marginally detected with >2.5σ significance. The best ...
Zhu Qualifier Solutions - University of Toronto Astronomy
... 3.1.5. How do you determine an a present-day mass function (PDMF) from an IMF? 3.2. Question 2 3.2.1. What Orbits are Allowed in an Axisymmetric Potential? 3.2.2. How did each population of stars gain their particular orbit? 3.2.3. Orbits in Elliptical Galaxies 3.2.4. What are the different populati ...
... 3.1.5. How do you determine an a present-day mass function (PDMF) from an IMF? 3.2. Question 2 3.2.1. What Orbits are Allowed in an Axisymmetric Potential? 3.2.2. How did each population of stars gain their particular orbit? 3.2.3. Orbits in Elliptical Galaxies 3.2.4. What are the different populati ...
The formation of disc galaxies in high-resolution moving
... particles whereas the rest of the simulation volume is filled with progressively higher mass particles whose mass grows with distance from the target galaxy. This saves computational time while still ensuring the correct cosmological tidal field and mass infall rate for the forming target galaxy. Th ...
... particles whereas the rest of the simulation volume is filled with progressively higher mass particles whose mass grows with distance from the target galaxy. This saves computational time while still ensuring the correct cosmological tidal field and mass infall rate for the forming target galaxy. Th ...
Accreting Neutron Stars: Strong Gravity and Type I Bursts
... Another technique under investigation is asteroseismology. This is a fairly new approach in NSs and is still at its very early stages. However, in principle, analyzing different frequencies found during the bursts of magnetars (NSs with magnetic fields above ∼ 1014 G, Watts, 2011), or the signals en ...
... Another technique under investigation is asteroseismology. This is a fairly new approach in NSs and is still at its very early stages. However, in principle, analyzing different frequencies found during the bursts of magnetars (NSs with magnetic fields above ∼ 1014 G, Watts, 2011), or the signals en ...
T Tauri stars Optical lucky imaging polarimetry of HL and XZ Tau
... bound sphere with mass higher than this mass should collapse because gravity overcomes the internal thermal pressure. This simplified equation does not account for magnetic field support, turbulence and radiation fields. Although, it is apparent that it is easier to form stars from a cold and dense ...
... bound sphere with mass higher than this mass should collapse because gravity overcomes the internal thermal pressure. This simplified equation does not account for magnetic field support, turbulence and radiation fields. Although, it is apparent that it is easier to form stars from a cold and dense ...
distribution and properties of a sample of massive young stars
... earliest stages of their evolution are therefore hidden behind many magnitudes of visual extinction, only observable at infrared (IR) and millimetre wavelengths. Moreover, massive stars are known to form exclusively in clusters (e.g. de Wit et al. 2004), which makes it difficult to attribute derived ...
... earliest stages of their evolution are therefore hidden behind many magnitudes of visual extinction, only observable at infrared (IR) and millimetre wavelengths. Moreover, massive stars are known to form exclusively in clusters (e.g. de Wit et al. 2004), which makes it difficult to attribute derived ...
Radial transport in the solar nebula: Implications for moderately
... were used to explain the chemical and isotopic properties of solar system materials as the result of their dynamical evolution in a protoplanetary disk. The disk began as a hot, compact object that cooled over time as it thinned as a result of mass and angular momentum transport. The rate of mass tr ...
... were used to explain the chemical and isotopic properties of solar system materials as the result of their dynamical evolution in a protoplanetary disk. The disk began as a hot, compact object that cooled over time as it thinned as a result of mass and angular momentum transport. The rate of mass tr ...
GLAST Science at Lunch - Aug 11, 2005
... made of a compact X-ray source orbiting a massive star. Using the VLA radio interferometer, Marti et al. 1998 identified LS 5039 as a nonthermal radio source, supporting the identification. New X-ray observations (Ribo et al. 1999) showed a hard spectrum, but neither pulsed nor periodic emission. Pa ...
... made of a compact X-ray source orbiting a massive star. Using the VLA radio interferometer, Marti et al. 1998 identified LS 5039 as a nonthermal radio source, supporting the identification. New X-ray observations (Ribo et al. 1999) showed a hard spectrum, but neither pulsed nor periodic emission. Pa ...
THE ORION NEBULA AND ITS ASSOCIATED POPULATION C. R. O
... Heliocentric velocities will be used throughout this review, these values being 18.1 km s−1 more positive than M 42 velocities in the Local Standard of Rest. A complete PI model of a freely expanding blister nebula would incorporate both the effects of the heating and cooling processes arising from ...
... Heliocentric velocities will be used throughout this review, these values being 18.1 km s−1 more positive than M 42 velocities in the Local Standard of Rest. A complete PI model of a freely expanding blister nebula would incorporate both the effects of the heating and cooling processes arising from ...
Analysis of Stellar Activity and Orbital Dynamics in Extrasolar
... The area of exoplanet research, which emerged less than two decades ago, was revolutionized with the advent of space-based photometers like CoRoT and Kepler. These observatories provide long-term monitoring of thousands of stars with unprecendented accuracy and high time resolution to detect transit ...
... The area of exoplanet research, which emerged less than two decades ago, was revolutionized with the advent of space-based photometers like CoRoT and Kepler. These observatories provide long-term monitoring of thousands of stars with unprecendented accuracy and high time resolution to detect transit ...
Munshi_washington_0250E_12611
... contribution of old stellar populations to the total stellar mass, leading to stellar mass errors of up to 50% for individual galaxies and highlight the importance of using proper techniques to compare simulations. Additionally, my work examines the pressure of the star-forming interstellar medium ( ...
... contribution of old stellar populations to the total stellar mass, leading to stellar mass errors of up to 50% for individual galaxies and highlight the importance of using proper techniques to compare simulations. Additionally, my work examines the pressure of the star-forming interstellar medium ( ...
The Celestial Sphere CHAPTER 1
... It is evident that for e D 0, hr i D a, as expected for perfectly circular motion. However, hr i deviates from a for other values of e. This function is most easily evaluted numerically. Employing a simple trapezoid method with 106 intervals, gives the results shown in Table S2.1. ...
... It is evident that for e D 0, hr i D a, as expected for perfectly circular motion. However, hr i deviates from a for other values of e. This function is most easily evaluted numerically. Employing a simple trapezoid method with 106 intervals, gives the results shown in Table S2.1. ...
O stars with weak winds: the Galactic case - Max-Planck
... 3.1. Stellar parameters The main stellar parameters have been determined from blue optical spectra. As such spectra contain diagnostic lines which are formed just above the photosphere and are not affected by winds, plane-parallel models can be used for a preliminary analysis. Hence, we have taken a ...
... 3.1. Stellar parameters The main stellar parameters have been determined from blue optical spectra. As such spectra contain diagnostic lines which are formed just above the photosphere and are not affected by winds, plane-parallel models can be used for a preliminary analysis. Hence, we have taken a ...
On the composition of GRBs` Collapsar jets
... ≤95 per cent (2σ ).5 The best-fitting plateaus extend from 5 to 25 s in the BATSE data (7.19/4 χ 2 /DOF), from 2.5 to 17 s in the FermiGBM data (10/5 χ 2 /DOF) and from 1 to 20 s in the Swift data (15.85/9 χ 2 /DOF). We account for three free parameters in our fit: the height of the plateau and the ...
... ≤95 per cent (2σ ).5 The best-fitting plateaus extend from 5 to 25 s in the BATSE data (7.19/4 χ 2 /DOF), from 2.5 to 17 s in the FermiGBM data (10/5 χ 2 /DOF) and from 1 to 20 s in the Swift data (15.85/9 χ 2 /DOF). We account for three free parameters in our fit: the height of the plateau and the ...
High-resolution radio emission from RCW 49/Westerlund 2
... diffuse emission pervades the field of view, but no clear structure could be identified. Fujita et al. (2009) analyzed Suzaku observations of Westerlund 2 and found diffuse X-ray emission consisting of thermal and maybe one nonthermal component1 . The extended TeV source HESS J1023−575 is positionally ...
... diffuse emission pervades the field of view, but no clear structure could be identified. Fujita et al. (2009) analyzed Suzaku observations of Westerlund 2 and found diffuse X-ray emission consisting of thermal and maybe one nonthermal component1 . The extended TeV source HESS J1023−575 is positionally ...
The effects of disk building on the distributions of refractory materials
... disk. Thus, those later formed high-temperature objects were less efficiently preserved. As such, Ciesla (2010) argued that due to the dynamics of those hightemperature products in the disk, CAIs would exhibit a small spread in formation ages, which was consistent with the observed ages of CAIs found ...
... disk. Thus, those later formed high-temperature objects were less efficiently preserved. As such, Ciesla (2010) argued that due to the dynamics of those hightemperature products in the disk, CAIs would exhibit a small spread in formation ages, which was consistent with the observed ages of CAIs found ...
Influence of extreme ultraviolet radiation on the Pv ionization fraction
... on the square of the density. Moreover, the ultraviolet P V resonance lines indicate a possible need for an even stronger reduction of hot star mass-loss rates, provided that P V is a dominant ionization stage of phosphorus, at least in some hot stars. The latter assumption is challenged by the poss ...
... on the square of the density. Moreover, the ultraviolet P V resonance lines indicate a possible need for an even stronger reduction of hot star mass-loss rates, provided that P V is a dominant ionization stage of phosphorus, at least in some hot stars. The latter assumption is challenged by the poss ...
The cometary composition of a protoplanetary disk as re
... scale of this enhancement factor varies among models, but it is at least one order of magnitude (Methods). This results in an expected minimum CH3 CN/HCN ice ratio of 0.5 at 30 AU in the ...
... scale of this enhancement factor varies among models, but it is at least one order of magnitude (Methods). This results in an expected minimum CH3 CN/HCN ice ratio of 0.5 at 30 AU in the ...
multiwavelength observations of the gamma-ray
... Blazars (BL Lac objects and gamma-ray loud flat spectrum radio quasars (FSRQs)) are the most extreme type of active galactic nuclei (AGNs). They were historically defined through extreme flux variability throughout the electromagnetic spectrum, and sometimes strong and variable linear polarization a ...
... Blazars (BL Lac objects and gamma-ray loud flat spectrum radio quasars (FSRQs)) are the most extreme type of active galactic nuclei (AGNs). They were historically defined through extreme flux variability throughout the electromagnetic spectrum, and sometimes strong and variable linear polarization a ...
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.