Star Wreck
... SECS type, their effect is negligible. If, however, they are SENS, they consume the white dwarf from the inside, just like in the case of a neutron star. The white dwarfs also become unstable when their masses become less than 2.2 × 10−3 M⊙ , at which ...
... SECS type, their effect is negligible. If, however, they are SENS, they consume the white dwarf from the inside, just like in the case of a neutron star. The white dwarfs also become unstable when their masses become less than 2.2 × 10−3 M⊙ , at which ...
Practice Paper Two
... One advantage of AC induction motors over other motors such as the universal motor is that AC induction motors: (A) ...
... One advantage of AC induction motors over other motors such as the universal motor is that AC induction motors: (A) ...
PoS(MQW6)077
... 5.1 Absorption Line Equivalent Width Amplitudes We expect that absorption lines from the mass donor will increase in strength relative to the continuum as SS 433 goes into eclipse and a larger fraction of the observed light is coming from ...
... 5.1 Absorption Line Equivalent Width Amplitudes We expect that absorption lines from the mass donor will increase in strength relative to the continuum as SS 433 goes into eclipse and a larger fraction of the observed light is coming from ...
ppt - CIERA-Northwestern
... evolution and dynamical interactions (binary-single and binarybinary) leads to a rapid depletion of the binary population in the cluster core. The maximum binary fraction today in the core of a typical dense cluster such as 47 Tuc, assuming an initial binary fraction of 100 per cent, is only ~5-10 p ...
... evolution and dynamical interactions (binary-single and binarybinary) leads to a rapid depletion of the binary population in the cluster core. The maximum binary fraction today in the core of a typical dense cluster such as 47 Tuc, assuming an initial binary fraction of 100 per cent, is only ~5-10 p ...
M BH
... Successively discovered with X-rays in nearby galaxies Luminosity is LX > 1039 erg s-1 > (LE of a neutron star) QSS (=quasi-soft source) may be low luminosity IMBHs (?) ...
... Successively discovered with X-rays in nearby galaxies Luminosity is LX > 1039 erg s-1 > (LE of a neutron star) QSS (=quasi-soft source) may be low luminosity IMBHs (?) ...
幻灯片 1
... Observation bias：It is more difficult to detect low mass planet lack of giant planet around low metallicity star lack of giant planet around young stars (low ...
... Observation bias：It is more difficult to detect low mass planet lack of giant planet around low metallicity star lack of giant planet around young stars (low ...
Search for Life in the Universe
... • Hollywood picture ignores basic physics, chemistry, biology, and astronomy • No credible UFO sighting (TBD in detail) • Our task: scientific search for life, based on physics, chemistry biology, and astronomy • Science evolves: we know today much more than we knew before • But science is also alwa ...
... • Hollywood picture ignores basic physics, chemistry, biology, and astronomy • No credible UFO sighting (TBD in detail) • Our task: scientific search for life, based on physics, chemistry biology, and astronomy • Science evolves: we know today much more than we knew before • But science is also alwa ...
A line-profile analysis of the large-amplitude β Cephei star ξ Canis
... In an effort to find frequencies other than the dominant one, ξ 1 CMa was monitored during 4.5 years with the coralie échelle spectrograph attached to the 1.2 m Euler telescope in La Silla (Chile). The observations took place between February 2000 and October 2004 and in total we gathered 401 high- ...
... In an effort to find frequencies other than the dominant one, ξ 1 CMa was monitored during 4.5 years with the coralie échelle spectrograph attached to the 1.2 m Euler telescope in La Silla (Chile). The observations took place between February 2000 and October 2004 and in total we gathered 401 high- ...
Formation of spiral and elliptical galaxies in a CDM cosmogony
... The attening of the halo (axial ratio 2:3) is too high to be a result of its rotation, i.e., it must be caused by the anisotropic velocity dispersion, while the attening of the bulge (axial ratio 1:1.3) is at least partially due to its rotation (v= 1). These results support the idea that disk ...
... The attening of the halo (axial ratio 2:3) is too high to be a result of its rotation, i.e., it must be caused by the anisotropic velocity dispersion, while the attening of the bulge (axial ratio 1:1.3) is at least partially due to its rotation (v= 1). These results support the idea that disk ...
The star-forming environment of an ultraluminous X-ray
... absolute astrometric registration of the three images. We estimate that we have thus reduced the astrometric error to <0.4 arcsec for the PC frame. We also applied this new astrometric registration to a mosaiced WFPC2 image, verifying that the error is 0.4 arcsec in all chips. The Chandra astrometr ...
... absolute astrometric registration of the three images. We estimate that we have thus reduced the astrometric error to <0.4 arcsec for the PC frame. We also applied this new astrometric registration to a mosaiced WFPC2 image, verifying that the error is 0.4 arcsec in all chips. The Chandra astrometr ...
Jeremy Heyl et al. (PDF document)
... for stellar evolution and gravitational dynamics, and the nearby rich cluster, 47 Tuc (47 Tuc), has long been a focus of such investigations. The key point of this investigation is the interplay between these two processes. In particular, in the core of 47 Tuc, the timescale for stellar evolution an ...
... for stellar evolution and gravitational dynamics, and the nearby rich cluster, 47 Tuc (47 Tuc), has long been a focus of such investigations. The key point of this investigation is the interplay between these two processes. In particular, in the core of 47 Tuc, the timescale for stellar evolution an ...
Line-profile tomography of exoplanet transits – II. A gas
... transits have previously been reported in the lightcurve obtained by the SuperWASP survey of the A5 star HD15082 (WASP-33; V = 8.3, v sin i = 86 km s−1 ). Here we report further photometry and time-series spectroscopy through three separate transits, which we use to confirm the existence of a gas gi ...
... transits have previously been reported in the lightcurve obtained by the SuperWASP survey of the A5 star HD15082 (WASP-33; V = 8.3, v sin i = 86 km s−1 ). Here we report further photometry and time-series spectroscopy through three separate transits, which we use to confirm the existence of a gas gi ...
Ultra faint dwarfs: probing early cosmic star formation
... et al. 2008) constitutes an extension towards lower metallicity of that of “classical“ dSphs (L > 105 L⊙ ). Such a continuous trend seems to exclude that processes (e.g. tidal stripc RAS ...
... et al. 2008) constitutes an extension towards lower metallicity of that of “classical“ dSphs (L > 105 L⊙ ). Such a continuous trend seems to exclude that processes (e.g. tidal stripc RAS ...
Presentazione di PowerPoint
... Beyond a few thousand Schwarzschild radii from the central SMBH, but within the sphere of influence, the motion of stars and gas is predominantly Keplerian (relativistic effects are minimal), with a component due to the combined gravitational potential of stars, dust, gas, dark matter, and anything ...
... Beyond a few thousand Schwarzschild radii from the central SMBH, but within the sphere of influence, the motion of stars and gas is predominantly Keplerian (relativistic effects are minimal), with a component due to the combined gravitational potential of stars, dust, gas, dark matter, and anything ...
Figure 1. Map showing the region of the Fourth Quadrant selected
... Bate & Zinnecker 1998). On the other hand, by adding turbulence to an accretion model, McKee & Tan (2003) have shown that massive stars can still form by accretion. More generally, the new “turbulent” models for star formation may explain the low star formation efficiency and turbulence observed acr ...
... Bate & Zinnecker 1998). On the other hand, by adding turbulence to an accretion model, McKee & Tan (2003) have shown that massive stars can still form by accretion. More generally, the new “turbulent” models for star formation may explain the low star formation efficiency and turbulence observed acr ...
PH607lec07
... is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the l ...
... is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the l ...
Observations with Herschel: High-mass star formation and the
... gas and dust between stars in galaxies – and how massive stars are able to form deep within the extremely large and ice cold gas clouds in the ISM. In Paper I, we present searches for a so far undetected key molecule in the interstellar nitrogen chemistry, NH+ , along with the anion NH− 2 . Despite ...
... gas and dust between stars in galaxies – and how massive stars are able to form deep within the extremely large and ice cold gas clouds in the ISM. In Paper I, we present searches for a so far undetected key molecule in the interstellar nitrogen chemistry, NH+ , along with the anion NH− 2 . Despite ...
Stars and Galaxies
... will become a giant, then a white dwarf, and finally a black dwarf. Stars more massive than the Sun can become supergiants and end up as neutron stars or black holes. Stars much lower in mass than the Sun, like the red dwarf star Proxima Centauri, could remain on the main sequence for 16 trillion ye ...
... will become a giant, then a white dwarf, and finally a black dwarf. Stars more massive than the Sun can become supergiants and end up as neutron stars or black holes. Stars much lower in mass than the Sun, like the red dwarf star Proxima Centauri, could remain on the main sequence for 16 trillion ye ...
Gravitational Radiation from Rotating White Dwarfs and
... There are a number of gravitational radiation detectors, planned, under construction, and operational covering a wide frequency spectrum from ~10-9Hz all the way up to~104Hz. The coverage of the spectrum is not complete and the gap between space-based interferometer and ground-based interferometers ...
... There are a number of gravitational radiation detectors, planned, under construction, and operational covering a wide frequency spectrum from ~10-9Hz all the way up to~104Hz. The coverage of the spectrum is not complete and the gap between space-based interferometer and ground-based interferometers ...
Bamberg_VanGrootel - ORBi
... Former close-in giant planets/BDs were deeply engulfed in the red giant envelope The planets’ volatile layers were removed and only the dense cores survived and ...
... Former close-in giant planets/BDs were deeply engulfed in the red giant envelope The planets’ volatile layers were removed and only the dense cores survived and ...
L69 CONVERSION OF NEUTRON STARS TO
... capable of releasing a total energy of a few times 1053 ergs. Many cosmological models for GRBs have been proposed. Among the most popular is the merging of two neutron stars (or a neutron star and a black hole) in a binary system (Paczyński 1998). Recent results (Janka & Ruffert 1996) within this ...
... capable of releasing a total energy of a few times 1053 ergs. Many cosmological models for GRBs have been proposed. Among the most popular is the merging of two neutron stars (or a neutron star and a black hole) in a binary system (Paczyński 1998). Recent results (Janka & Ruffert 1996) within this ...
Essential Question
... including stars, nebulae, and galaxies, and use models such as the Hertsprung-Russell diagram for classification 8.8(E) research how scientific data are used as evidence to develop scientific theories to describe the origin of the universe ...
... including stars, nebulae, and galaxies, and use models such as the Hertsprung-Russell diagram for classification 8.8(E) research how scientific data are used as evidence to develop scientific theories to describe the origin of the universe ...
400 Years of Stellar Rotation
... rotation interaction in the infrared have been enabled for a wider range of ages and masses than ever before. ...
... rotation interaction in the infrared have been enabled for a wider range of ages and masses than ever before. ...
Deep fields around bright stars (“Galaxies around Stars”)
... PUEO/CFHT deep field observations NACO/VLT Science Verification phase: the Casertano Deep field ...
... PUEO/CFHT deep field observations NACO/VLT Science Verification phase: the Casertano Deep field ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.