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A cold detached dust envelope around an oxygen-rich Mira
A cold detached dust envelope around an oxygen-rich Mira

... case (Hashimoto 1994, 1995). (4) Or, some circumstellar mechanisms other than dust grains may produce the infrared excess. For example, strong line emission from circumstellar molecules such as H2 O may cause the reddening. In any case, there must be some physical conditions which are unknown in the ...
All About Elements
All About Elements

... in the universe. Only Hydrogen is more abundant! These two elements were copiously formed during the creation of the universe. In the early stages of the universe, helium and hydrogen nuclei were actually formed. No atoms were formed until about 300,000 years after the Big Bang took place, when the ...
Early-type stars in the core of the young open cluster Westerlund 2
Early-type stars in the core of the young open cluster Westerlund 2

... is dominated by strong and broad H  Balmer lines. Weak absorption lines of He  λλ 4388, 4471, Mg  λ 4481 and Si  λ 4552 are also seen. The He  λ 4471/Mg  λ 4481 intensity ratio indicates a spectral type B8-A0. The appearance of some weak metallic lines favours an A0 classification, whilst ...
The spectroscopic Hertzsprung
The spectroscopic Hertzsprung

... these stars remain almost constant during this evolution, it will thus be difficult to distinguish whether an observed star is on the redward or on the blueward part of the track. While it remains hidden in the HR diagram, the sHR diagram reveals nicely that the mass loss drives these stars towards ...
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Document

... universe) ...
Stars & Galaxies - newmanlib.ibri.org
Stars & Galaxies - newmanlib.ibri.org

... Lifespan of a G Star • When it uses up the H in its core, it expands to form a red giant, burning H in an outer shell & He in the core. • When the He is gone, the star collapses to form a white dwarf. • The dwarf gradually cools till it ceases to shine, becoming a black dwarf. ...
Science with IMACS on Magellan
Science with IMACS on Magellan

ALMA - ESO
ALMA - ESO

... Herschel is best suited for surveys, ALMA a followup instrument ALMA has a small Field Of View (FOV), but high angular resolution and sensitivity Higher angular resolution to image the sources measured by Herschel Follow up to sources discovered with PACS or SPIRE in longer wavelength dust emission ...
GALAXIES 626
GALAXIES 626

... Kinematics and structure of the thick disk rotational lag ~ 30 km/s near the sun and increases by about 30 km s-1 kpc-1 with height above the plane velocity dispersion in (U,V,W) = (46, 50, 35) km/s radial scale length = 3.5 to 4.5 kpc : uncertain scale height from star counts = 800 to 1200 pc (thi ...
A Comet-Hunter`s Legacy -
A Comet-Hunter`s Legacy -

... their hottest, brightest stars -- stars that are burning their fuel so quickly that they are nearly at the end of their Main Sequence lives -- are much brighter than the hottest, brightest stars in other globular clusters, and can't be much more than half a ...
2. The X-ray-Radio correlation for bulgeless galaxies
2. The X-ray-Radio correlation for bulgeless galaxies

... Fig. 21: The VLA-COSMOS Large Project Survey as obtained with the NRAO's VLA. A section of the survey as been zoomed to allow for a better visualization of the sources...............................................................45 Fig. 22: Flux distribution for the radio-detected sources as captur ...
IAC_L2_thindisk
IAC_L2_thindisk

... the disk, e.g. via Jeans equation. Is there more matter in the disk that we can account for from census of visible objects ? The tracer sample must be in equilibrium so the stars need to be older than a few Gyr. The last few estimates have used K dwarfs and K giants - probably OK but they do include ...
Stellar Remnants White Dwarfs Type Ia Supernovae Neutron Stars
Stellar Remnants White Dwarfs Type Ia Supernovae Neutron Stars

... © 2007 Pearson Education Inc., publishing as Pearson Addison-Wesley ...
AR2012 - Vatican Observatory
AR2012 - Vatican Observatory

... binoculars equipped with solar filters. In addition, the Vatican Observatory’s Coronado Solar Telescope, attached to the large Visual refractor telescope on the Papal Palace roof, was connected to a new CCD imaging camera and computer network, recently provided to the Observatory from the Governator ...
Evolution of stars
Evolution of stars

... e. combines four hydrogen nuclei to form one helium nucleus, which produces energy. 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 fr ...
A Digital Spectral Classification Atlas
A Digital Spectral Classification Atlas

... spectra are presented in a rectified intensity versus wavelength format, in which the spectral continuum has been normalized to unity. The 3.6Å resolution spectra, for the most part, are presented in a flux versus wavelength format; this format provides additional information on ...
Mn, Cu, and Zn abundances in barium stars and their correlations
Mn, Cu, and Zn abundances in barium stars and their correlations

... intermediate mass AGB stars, and the weak component of the s-process, thought to be sited at He-burning cores of M ≥ 10 M stars (see Raiteri et al. 1993; Matteucci et al. 1993; Mishenina et al. 2002, and references therein). Even though their positions in the periodic table are contiguous, their be ...
LIGO I - Indico
LIGO I - Indico

... GWs aren’t just a new band, they’re a new spectrum, with very different and complementary properties to EM waves. • Vibrations of space-time, not in space-time • Emitted by coherent motion of huge masses moving at near light-speed; not vibrations of electrons in atoms • Can’t be absorbed, scattered, ...
The Evolution of Isotope Ratios in the Milky Way Galaxy
The Evolution of Isotope Ratios in the Milky Way Galaxy

... metals are produced. This assumption may not be valid but does not affect the average chemical evolution of galaxies. Super AGB stars — The fate of stars with initial masses between about 8 − 10M⊙ is uncertain. The upper limit of AGB stars, Mu,1 , is defined as the minimum mass for carbon ignition, ...
GRB EXPERIMENT
GRB EXPERIMENT

... • Note that the definition does not specify the magnetic field strength • To explain SGRs and AXPs, however, B must be greater than the quantum critical value 4.4 x 1013 G, where the energy between electron Landau levels equals their rest mass • Some AXPs and SGRs require B~1015 Gauss, so these magn ...
SherwoodWA_1973redux - Edinburgh Research Archive
SherwoodWA_1973redux - Edinburgh Research Archive

... A General View ...
Galaxies - hwchemistry
Galaxies - hwchemistry

... neutron stars. – Astronomers don’t see the X rays these objects would emit. – There is 10 to 100 times more dark matter than visible matter. – That many black holes would produce X rays that would be easy to detect. ...
Founders of Modern Astronomy
Founders of Modern Astronomy

Evidence for the Tidal Destruction of Hot Jupiters by Subgiant Stars
Evidence for the Tidal Destruction of Hot Jupiters by Subgiant Stars

... Figure 2. Galactic U V W kinematics of subgiant stars that host exoplanets discovered with the radial-velocity technique. In each panel, we plot the U V W space motions of the subgiant sample as blue points and the density of points in a control sample selected from the Hipparcos catalog as the back ...
Review: How does a star`s mass determine its life story?
Review: How does a star`s mass determine its life story?

... • size R ~ thousands of kilometers • mass M ~ mass of stars • density absurdly high: – white dwarf matter is roughly a million times more dense than water atomic density ...
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Future of an expanding universe

Observations suggest that the expansion of the universe will continue forever. If so, the universe will cool as it expands, eventually becoming too cold to sustain life. For this reason, this future scenario is popularly called the Big Freeze.If dark energy—represented by the cosmological constant, a constant energy density filling space homogeneously, or scalar fields, such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space—accelerates the expansion of the universe, then the space between clusters of galaxies will grow at an increasing rate. Redshift will stretch ancient, incoming photons (even gamma rays) to undetectably long wavelengths and low energies. Stars are expected to form normally for 1012 to 1014 (1–100 trillion) years, but eventually the supply of gas needed for star formation will be exhausted. And as existing stars run out of fuel and cease to shine, the universe will slowly and inexorably grow darker, one star at a time. According to theories that predict proton decay, the stellar remnants left behind will disappear, leaving behind only black holes, which themselves eventually disappear as they emit Hawking radiation. Ultimately, if the universe reaches a state in which the temperature approaches a uniform value, no further work will be possible, resulting in a final heat death of the universe.
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