Document
... been a supernova in our Galaxy … we are still waiting! But, in a nearby galaxy not long ago (February 1987)… ...
... been a supernova in our Galaxy … we are still waiting! But, in a nearby galaxy not long ago (February 1987)… ...
- Mineralogical Society of America
... H burning on the surface, which is observed as a nova. The typical nucleosynthesis occurring in novae is explosive H burning, which produces 15N, 22Na, and 26Al via proton captures on CNO nuclei (e.g., Wiescher et al. 1986). If the white dwarf gains enough mass from the companion star to the level o ...
... H burning on the surface, which is observed as a nova. The typical nucleosynthesis occurring in novae is explosive H burning, which produces 15N, 22Na, and 26Al via proton captures on CNO nuclei (e.g., Wiescher et al. 1986). If the white dwarf gains enough mass from the companion star to the level o ...
white_paper.word - Space Telescope Science Institute
... power exceeding HST's by a factor of twenty, and with augmented technologies such as adaptive optics even smaller telescopes (3-5 meter class) can, under the right conditions, yield superior spatial resolutions. Such facilities are beginning to challenge the observational uniqueness space, which onc ...
... power exceeding HST's by a factor of twenty, and with augmented technologies such as adaptive optics even smaller telescopes (3-5 meter class) can, under the right conditions, yield superior spatial resolutions. Such facilities are beginning to challenge the observational uniqueness space, which onc ...
Molecular clumps in the W51 giant molecular cloud
... main regions W51A and W51B, identified by their radio emission (Kundu & Velusamy 1967; Mufson & Liszt 1979; Kumar et al. 2004). More recently, this decomposition has been based on radial velocity data of the W51 GMC into the W51 complex and the high-velocity stream (HVS; Carpenter & Sanders 1998; Ko ...
... main regions W51A and W51B, identified by their radio emission (Kundu & Velusamy 1967; Mufson & Liszt 1979; Kumar et al. 2004). More recently, this decomposition has been based on radial velocity data of the W51 GMC into the W51 complex and the high-velocity stream (HVS; Carpenter & Sanders 1998; Ko ...
dust mass
... - thermonuclear explosions of C+O white dwarfs with the mass close to Chandrasekhar limit (~1.4 Msun) ・ deflagration (Nomoto+76, 84) ➔ subsonic wave, unburned C in the outer layer ...
... - thermonuclear explosions of C+O white dwarfs with the mass close to Chandrasekhar limit (~1.4 Msun) ・ deflagration (Nomoto+76, 84) ➔ subsonic wave, unburned C in the outer layer ...
i.3. - adaptive optics overview
... large telescopes augmented with adaptive optics systems. Some programs, which could once only have been attempted from space, might now be possible with suitable instrumentation on such ground-based facilities. Yet, many of these systems are still in there early evolutionary stages and their theoret ...
... large telescopes augmented with adaptive optics systems. Some programs, which could once only have been attempted from space, might now be possible with suitable instrumentation on such ground-based facilities. Yet, many of these systems are still in there early evolutionary stages and their theoret ...
Infrared identification of high-mass X
... Aims. We present here new infrared observations from which to reveal or constrain the nature of 15 INTEGRAL sources, which allow us to update and discuss the Galactic HMXB population statistics. Methods. After previous photometric and spectroscopic observing campaigns in the optical and near-infrare ...
... Aims. We present here new infrared observations from which to reveal or constrain the nature of 15 INTEGRAL sources, which allow us to update and discuss the Galactic HMXB population statistics. Methods. After previous photometric and spectroscopic observing campaigns in the optical and near-infrare ...
X-ray binaries in the Milky Way and other galaxies
... 4.1. Comparison of the differential Log(N)–Log(S) relation for Galactic XRBs from ASM and ASCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Comparison of the number-flux relation observed in the ASCA GRS and the predicted Log(N)–Log(S) from ASM luminosity functions. . . . . . . . . ...
... 4.1. Comparison of the differential Log(N)–Log(S) relation for Galactic XRBs from ASM and ASCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Comparison of the number-flux relation observed in the ASCA GRS and the predicted Log(N)–Log(S) from ASM luminosity functions. . . . . . . . . ...
Modeling Spatially and Spectrally Resolved Observations to
... In extragalactic astronomy, a central challenge is that we cannot directly watch what happens to galaxies before and after they are observed. This dissertation focuses on linking predictions of galaxy time-evolution directly with observations, evaluating how interactions, mergers, and other processe ...
... In extragalactic astronomy, a central challenge is that we cannot directly watch what happens to galaxies before and after they are observed. This dissertation focuses on linking predictions of galaxy time-evolution directly with observations, evaluating how interactions, mergers, and other processe ...
the mass distribution and lifetime of prestellar cores in perseus
... (2 ; 10 4 10 6 cm 3 ;7 Enoch et al. 2007), however, and the cores may not be truly prestellar. In Orion, Nutter & Ward-Thompson (2007) find a turnover in the CMD of starless SCUBA 850 m cores at 1.3 M. Those authors relate this turnover to a downturn in the Kroupa (2002) IMF at 0.1 M, and infe ...
... (2 ; 10 4 10 6 cm 3 ;7 Enoch et al. 2007), however, and the cores may not be truly prestellar. In Orion, Nutter & Ward-Thompson (2007) find a turnover in the CMD of starless SCUBA 850 m cores at 1.3 M. Those authors relate this turnover to a downturn in the Kroupa (2002) IMF at 0.1 M, and infe ...
High-mass X-ray Binaries: X-raying the winds Ángel Giménez García
... XSPEC, versión 12.8.08 , especializado en el ajuste de modelos a espectros de rayos X. En la Tabla 4.2 presentamos todos los modelos del continuo que hemos probado en cada uno de los espectros analizados. Los modelos has sido aceptados o rechazados en función del χ2 -reducido asociado a cada ajuste ...
... XSPEC, versión 12.8.08 , especializado en el ajuste de modelos a espectros de rayos X. En la Tabla 4.2 presentamos todos los modelos del continuo que hemos probado en cada uno de los espectros analizados. Los modelos has sido aceptados o rechazados en función del χ2 -reducido asociado a cada ajuste ...
Pluto: improved astrometry from 19 years of observations ⋆⋆⋆⋆⋆⋆
... Methods. All astrometric positions of Pluto were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as the reference catalog. We also used the planetary ephemeris DE421+plu021 for comparisons. The positions were cor ...
... Methods. All astrometric positions of Pluto were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as the reference catalog. We also used the planetary ephemeris DE421+plu021 for comparisons. The positions were cor ...
The impact of protocluster environments at z = 1.6
... The distributions of control field and intergroup galaxies in colour–mass space are very similar. Galaxies in both samples populate a red sequence at z − J ∼ 1.7 and a blue cloud at 0.5 < z − J < 1.2. The sample of control and intergroup galaxies are incomplete at almost all masses due to the asse ...
... The distributions of control field and intergroup galaxies in colour–mass space are very similar. Galaxies in both samples populate a red sequence at z − J ∼ 1.7 and a blue cloud at 0.5 < z − J < 1.2. The sample of control and intergroup galaxies are incomplete at almost all masses due to the asse ...
Particle Physics from Stars
... included in the 1998 edition of the Review of Particle Physics [ 3]. My 1996 book Stars as Laboratories for Fundamental Physics [ 4] treats these topics in much greater detail than is possible here. The present chapter is intended as a compact, up-to-date, and easily accessible source for the most i ...
... included in the 1998 edition of the Review of Particle Physics [ 3]. My 1996 book Stars as Laboratories for Fundamental Physics [ 4] treats these topics in much greater detail than is possible here. The present chapter is intended as a compact, up-to-date, and easily accessible source for the most i ...
PPT - IAC
... The first extensive CCD morphological studies had appeared: Jewitt et al 1986 ApJ 302, 727 44 PNe (haloes) Chu et al. 1987 ApJS 64, 529 ~100 PNe (multiple-shells) Balick 1987 AJ 94, 671 51 PNe and a morphological sequence (round elliptical butterfly ) linked with the Generalised Interacting Stel ...
... The first extensive CCD morphological studies had appeared: Jewitt et al 1986 ApJ 302, 727 44 PNe (haloes) Chu et al. 1987 ApJS 64, 529 ~100 PNe (multiple-shells) Balick 1987 AJ 94, 671 51 PNe and a morphological sequence (round elliptical butterfly ) linked with the Generalised Interacting Stel ...
Full Text - University of Toronto Astronomy
... In this dissertation, we develop new tools for the study of stellar atmospheres, pulsating stellar atmospheres and mass loss from pulsating stars. These tools provide new insights into the structure and evolution of stars and complement modern observational techniques such as optical interferometry ...
... In this dissertation, we develop new tools for the study of stellar atmospheres, pulsating stellar atmospheres and mass loss from pulsating stars. These tools provide new insights into the structure and evolution of stars and complement modern observational techniques such as optical interferometry ...
Liverpool Telescope 2: a new robotic facility for rapid transient follow
... explosion and the ensuing nucleosynthesis (e.g. the transition from deflagration to detonation). Turbulent deflagration models (Hillebrandt and Niemeyer, 2000; Röpke et al, 2007) of SNe Ia predict a large amount of unburned carbon and oxygen in the outer layers of the ejecta whereas delayed detonat ...
... explosion and the ensuing nucleosynthesis (e.g. the transition from deflagration to detonation). Turbulent deflagration models (Hillebrandt and Niemeyer, 2000; Röpke et al, 2007) of SNe Ia predict a large amount of unburned carbon and oxygen in the outer layers of the ejecta whereas delayed detonat ...
Ch a n d
... Pre-main-sequence stars exhibit complex magnetic activity, accretion, and various kinds of mass outflow. The impact of plasma onto the stellar surface from magnetospheric accretion streams, can be a dominant source of energy and momentum in the upper atmospheres of T Tauri stars. We present models i ...
... Pre-main-sequence stars exhibit complex magnetic activity, accretion, and various kinds of mass outflow. The impact of plasma onto the stellar surface from magnetospheric accretion streams, can be a dominant source of energy and momentum in the upper atmospheres of T Tauri stars. We present models i ...
Giant Low Surface Brightness Galaxies
... the gas is far more extended than the stellar disks (Pickering et al. 1997; de Blok et al. 1995). But although the HI masses are large, the HI gas surface densities in M pc−2 are much lower than that of normal late type spirals (de Blok et al. 1996). The thinness of the HI distribution has import ...
... the gas is far more extended than the stellar disks (Pickering et al. 1997; de Blok et al. 1995). But although the HI masses are large, the HI gas surface densities in M pc−2 are much lower than that of normal late type spirals (de Blok et al. 1996). The thinness of the HI distribution has import ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.