Who’s Afraid of a Stellar Superflare? Rachel Osten GSFC
... •planets might be unlikely to form around 1 star in an active binary, but Quintana & Lissauer (2006) demonstrate that planetary systems can form around close binary stars ...
... •planets might be unlikely to form around 1 star in an active binary, but Quintana & Lissauer (2006) demonstrate that planetary systems can form around close binary stars ...
Star Gauging (Star Counting)
... advances, the radiant rises higher in the northeast, the meteors arrive more nearly straight down, and so we see more of them. By the time morning twilight begins, the radiant has climbed to around 60° altitude for observers at midnorthern latitudes. If it’s cloudy on the peak night, don’t despair; ...
... advances, the radiant rises higher in the northeast, the meteors arrive more nearly straight down, and so we see more of them. By the time morning twilight begins, the radiant has climbed to around 60° altitude for observers at midnorthern latitudes. If it’s cloudy on the peak night, don’t despair; ...
Class 4 Galaxies Galaxy Classification Formation of Galaxies
... background (CMB) radiation. Therefore the CMB is a picture of the universe at the end of this epoch. ...
... background (CMB) radiation. Therefore the CMB is a picture of the universe at the end of this epoch. ...
Stellar Winds and Hydrodynamic Atmospheres of Stars
... Kudritzki, Mendez et al., 1997, Proc. IAU Symp. 180, 64 Kudritzki et al., 2006, Proc. IAU Symp. 234, 119 ...
... Kudritzki, Mendez et al., 1997, Proc. IAU Symp. 180, 64 Kudritzki et al., 2006, Proc. IAU Symp. 234, 119 ...
TRIFFID photometry of globular cluster cores – I. Photometric
... tilt correction can be achieved either in real time by low-order AO, or after the exposure by simple shift-and-add image sharpening in the manner described by Redfern (1991) and Redfern et al. (1992), a technique known as post-exposure image sharpening (PEIS). Given suitable photon-counting detector ...
... tilt correction can be achieved either in real time by low-order AO, or after the exposure by simple shift-and-add image sharpening in the manner described by Redfern (1991) and Redfern et al. (1992), a technique known as post-exposure image sharpening (PEIS). Given suitable photon-counting detector ...
Core Collapse Supernovae and Neutron Star Kicks, a Primer David
... Core collapse supernovae represent the last stages in the life of high mass stars. Stars above the Chandrasekhar limit of ~1.4 solar masses will undergo a supernova once nuclear burning at their core can no longer support the mass of the star from gravitational collapse (Slide 2 shows the life cycle ...
... Core collapse supernovae represent the last stages in the life of high mass stars. Stars above the Chandrasekhar limit of ~1.4 solar masses will undergo a supernova once nuclear burning at their core can no longer support the mass of the star from gravitational collapse (Slide 2 shows the life cycle ...
4. Stars and resolved stellar populations
... III]/Hβ ratio is a crucial indicator of fast shocks with speed above 100 km/s, while [S II] 6716/6731, [NII]/[O I], and [SII]/[O I] provide direct estimates of, respectively, the jet electronic density, ionization fraction and temperature, with much less dependence on the heating process than ratios ...
... III]/Hβ ratio is a crucial indicator of fast shocks with speed above 100 km/s, while [S II] 6716/6731, [NII]/[O I], and [SII]/[O I] provide direct estimates of, respectively, the jet electronic density, ionization fraction and temperature, with much less dependence on the heating process than ratios ...
PDF hosted at the Radboud Repository of the Radboud University
... et al. 2003). Results for nine binaries discovered in the SPY survey were presented in Papers I–V (Napiwotzki et al. 2001, 2002; Karl et al. 2003; Nelemans et al. 2005; Geier et al. 2010a). Subluminous B stars, which are also known as hot sudwarf stars, display the same spectral characteristics as m ...
... et al. 2003). Results for nine binaries discovered in the SPY survey were presented in Papers I–V (Napiwotzki et al. 2001, 2002; Karl et al. 2003; Nelemans et al. 2005; Geier et al. 2010a). Subluminous B stars, which are also known as hot sudwarf stars, display the same spectral characteristics as m ...
Groups of Stars
... Macalester and Eagle Lake Observatory – see dates on calendar • Apr. 24, 25, 28 & May 1 ...
... Macalester and Eagle Lake Observatory – see dates on calendar • Apr. 24, 25, 28 & May 1 ...
CHP 14
... a. the material will produce synchrotron radiation because of the strong magnetic field. b. hydrogen nuclei begin to fuse and emit high energy photons. c. the material will become hot enough that it will radiate most strongly at x-ray wavelengths. d. as the material slows down it converts thermal en ...
... a. the material will produce synchrotron radiation because of the strong magnetic field. b. hydrogen nuclei begin to fuse and emit high energy photons. c. the material will become hot enough that it will radiate most strongly at x-ray wavelengths. d. as the material slows down it converts thermal en ...
Neutron Stars and Black Holes
... The orbit of the binary pulsar, PSR 1936+16, studied by Taylor and Hulse a. is so small that the orbital period is smaller than the pulsar period. b. is growing smaller, presumably by emitting gravitational waves. c. provides evidence that it is being orbited by at least 6 planets the size of Jupite ...
... The orbit of the binary pulsar, PSR 1936+16, studied by Taylor and Hulse a. is so small that the orbital period is smaller than the pulsar period. b. is growing smaller, presumably by emitting gravitational waves. c. provides evidence that it is being orbited by at least 6 planets the size of Jupite ...
in the milky way - Chandra X
... Additional telescopes have also found other exotic members of this cosmic zoo. Infrared and radio observations find giant molecular clouds (Sagittarius A, B1, B2, and C, and the Cold Gas Cloud near the Radio Arc) where stars form. Normally too cool to be detected in X-rays, the edges of these clouds ...
... Additional telescopes have also found other exotic members of this cosmic zoo. Infrared and radio observations find giant molecular clouds (Sagittarius A, B1, B2, and C, and the Cold Gas Cloud near the Radio Arc) where stars form. Normally too cool to be detected in X-rays, the edges of these clouds ...
Chapter15 (with interactive links)
... The stars in globular clusters in the halo have some heavy elements, so at least one prior generation of stars must have existed. Halo objects were formed before interstellar gas was all concentrated into the disk. Later star formation has been concentrated in the disk. ...
... The stars in globular clusters in the halo have some heavy elements, so at least one prior generation of stars must have existed. Halo objects were formed before interstellar gas was all concentrated into the disk. Later star formation has been concentrated in the disk. ...
Physica 133-11f: Sample Final Exam Here are sample questions for
... 8) Why are we unlikely to find Earth-like planets around halo stars in the Galaxy? A) Halo stars do not have enough mass to hold onto planets. B) Planets around stars are known to be extremely rare. C) Halo stars formed in an environment where there were few heavy elements to create rocky planets. D ...
... 8) Why are we unlikely to find Earth-like planets around halo stars in the Galaxy? A) Halo stars do not have enough mass to hold onto planets. B) Planets around stars are known to be extremely rare. C) Halo stars formed in an environment where there were few heavy elements to create rocky planets. D ...
The radial scale length of the Milky Way
... by choosing the most appropriate conditions for this task. This value is similar to typical values for other galaxies (de Grijs and van der Kruit, 1996; Peletier et al., 1994; de Jong, 1996). This value seems quite low when compared with the obtained values in the optical (see for instance van der K ...
... by choosing the most appropriate conditions for this task. This value is similar to typical values for other galaxies (de Grijs and van der Kruit, 1996; Peletier et al., 1994; de Jong, 1996). This value seems quite low when compared with the obtained values in the optical (see for instance van der K ...
Big Dipper’s Binary Star Has Surprises
... Scientists led by John Werren, a professor of biology, and Stephen Richards of the Genome Sequencing Center at the Baylor College of Medicine have sequenced the genomes of three parasitoid wasp species, a project that could be useful for pest control and medicine. Because parasitoid wasps seek out a ...
... Scientists led by John Werren, a professor of biology, and Stephen Richards of the Genome Sequencing Center at the Baylor College of Medicine have sequenced the genomes of three parasitoid wasp species, a project that could be useful for pest control and medicine. Because parasitoid wasps seek out a ...
full text pdf
... cooler white dwarf sample of Bergeron, Saffer & Liebert (1992), then the hydrogen layer mass must be considerably less than 1 0 - 4 M * . In this context, Mh < 1 0 - 6 M * suffices, and this is not surprising, given that the two major channels of spectral evolution will have DA stars through the 30 ...
... cooler white dwarf sample of Bergeron, Saffer & Liebert (1992), then the hydrogen layer mass must be considerably less than 1 0 - 4 M * . In this context, Mh < 1 0 - 6 M * suffices, and this is not surprising, given that the two major channels of spectral evolution will have DA stars through the 30 ...
NAAP 3 of 7 Determining Astronomical Distance
... Intensities panel that for the star to have any helium lines it must be a very hot blue star. By dragging the vertical cursor we can see that for the star to have very strong helium and moderate ionized helium lines it must either be O6 or O7. Since the spectral lines are all very thick, we can assu ...
... Intensities panel that for the star to have any helium lines it must be a very hot blue star. By dragging the vertical cursor we can see that for the star to have very strong helium and moderate ionized helium lines it must either be O6 or O7. Since the spectral lines are all very thick, we can assu ...
A method for determining the V magnitude of asteroids from CCD
... comparison, CMC14 contains almost 40 times as many stars as Tycho: hence its suitability as a potential source of comparison stars. Table 3 lists the uncertainties quoted for the magnitude of individual stars in CMC14 depending on their brightness. It can be seen that fainter than r'=15, the error i ...
... comparison, CMC14 contains almost 40 times as many stars as Tycho: hence its suitability as a potential source of comparison stars. Table 3 lists the uncertainties quoted for the magnitude of individual stars in CMC14 depending on their brightness. It can be seen that fainter than r'=15, the error i ...
Review: How does a star`s mass determine its life story?
... According to the conservation of angular momentum, what would happen if a star orbiting in a direction opposite the neutron’s star rotation fell onto a neutron star? A. The neutron star’s rotation would speed up. B. The neutron star’s rotation would slow down. C. Nothing. The directions would cancel ...
... According to the conservation of angular momentum, what would happen if a star orbiting in a direction opposite the neutron’s star rotation fell onto a neutron star? A. The neutron star’s rotation would speed up. B. The neutron star’s rotation would slow down. C. Nothing. The directions would cancel ...
![arXiv:1102.4757v1 [astro-ph.SR] 23 Feb 2011](http://s1.studyres.com/store/data/017735077_1-cb16692362fed9e2a0fe2690d128f0ce-300x300.png)
arXiv:1102.4757v1 [astro-ph.SR] 23 Feb 2011
... al. 2003). Results for nine binaries discovered in the SPY survey were presented in papers I-V (Napiwotzki et al. 2001, 2002; Karl et al. 2003; Nelemans et al. 2005; Geier et al. 2010a). Subluminous B stars, which are also known as hot sudwarf stars, display the same spectral characteristics as main ...
... al. 2003). Results for nine binaries discovered in the SPY survey were presented in papers I-V (Napiwotzki et al. 2001, 2002; Karl et al. 2003; Nelemans et al. 2005; Geier et al. 2010a). Subluminous B stars, which are also known as hot sudwarf stars, display the same spectral characteristics as main ...
Oscillation Modes of Strange Quark Stars with a Strangelet Crust
... R? are the mass and radius of the star and A is the Schwarzschild gradient for local convective stability. In our analysis, we set A=0 for the bare strange star, although finite temperature effects or composition gradients can change the situation. This system of pulsation equations is solved numeri ...
... R? are the mass and radius of the star and A is the Schwarzschild gradient for local convective stability. In our analysis, we set A=0 for the bare strange star, although finite temperature effects or composition gradients can change the situation. This system of pulsation equations is solved numeri ...
BREATHING IN LOW MASS GALAXIES: A STUDY - N
... held off significant SF until intermediate ages (e.g. Bullock et al. 2000; Skillman et al. 2003; Gnedin & Kravtsov 2006; Read et al. 2006), but such a mechanism makes it hard to explain either the significant populations of ...
... held off significant SF until intermediate ages (e.g. Bullock et al. 2000; Skillman et al. 2003; Gnedin & Kravtsov 2006; Read et al. 2006), but such a mechanism makes it hard to explain either the significant populations of ...
No Slide Title
... Mass: similar to the Sun’s Diameter: about that of the Earth Hot (at least initially): 25,000 K; Dim (very small) Light they emit comes from heat (blackbody) Carbon and Oxygen; thin H/He surface layer White dwarf will cool over time (many billion of years) until it becomes a black dwarf em ...
... Mass: similar to the Sun’s Diameter: about that of the Earth Hot (at least initially): 25,000 K; Dim (very small) Light they emit comes from heat (blackbody) Carbon and Oxygen; thin H/He surface layer White dwarf will cool over time (many billion of years) until it becomes a black dwarf em ...
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.