shell properties
... Based on observations made with the Canada-France-Hawaii telescope, operated by CNRS, NRCC and UH, and on dearchived observations made with the NASA/ESA Hubble Space Telescope, operated by AURA Inc., under NASA contract NAS5-26555 ...
... Based on observations made with the Canada-France-Hawaii telescope, operated by CNRS, NRCC and UH, and on dearchived observations made with the NASA/ESA Hubble Space Telescope, operated by AURA Inc., under NASA contract NAS5-26555 ...
A CHANDRA X-RAY STUDY OF THE DENSE GLOBULAR CLUSTER TERZAN... C. O. Heinke, P. D. Edmonds, J. E. Grindlay, and...
... to the GSC 2.2 frame, based on the scatter of the two stars used in the boresighting. An additional error of 0>37 (following EGC01) is incurred in the shift between the GSC 2.2 and HST NICMOS frames. Combining these with the 0>2 centering positional uncertainty gives an error for the position in the ...
... to the GSC 2.2 frame, based on the scatter of the two stars used in the boresighting. An additional error of 0>37 (following EGC01) is incurred in the shift between the GSC 2.2 and HST NICMOS frames. Combining these with the 0>2 centering positional uncertainty gives an error for the position in the ...
ppt - chris.engelbrecht.nithep.ac.za
... radius of 22 arcseconds at the 60 kpc distance of the SMC. The spectrum of the blast wave yields a temperature of kTx 0.8 keV and an ionization timescale n e t ~ 11011 cm3s . 1. Based on the temperature, what is the shock velocity? Assuming the SNR is calculate the age. How does this compare ...
... radius of 22 arcseconds at the 60 kpc distance of the SMC. The spectrum of the blast wave yields a temperature of kTx 0.8 keV and an ionization timescale n e t ~ 11011 cm3s . 1. Based on the temperature, what is the shock velocity? Assuming the SNR is calculate the age. How does this compare ...
STELLAR SPECTRA A. Basic Line Formation
... These three exercises concern the appearance and nature of spectral lines in stellar spectra. Stellar spectrometry laid the foundation of astrophysics in the hands of: – Wollaston (1802): first observation of spectral lines in sunlight; – Fraunhofer (1814–1823): rediscovery of spectral lines in sunl ...
... These three exercises concern the appearance and nature of spectral lines in stellar spectra. Stellar spectrometry laid the foundation of astrophysics in the hands of: – Wollaston (1802): first observation of spectral lines in sunlight; – Fraunhofer (1814–1823): rediscovery of spectral lines in sunl ...
Introduction_to_pulsar_astronomy
... They are Galactic radio sources, as they are found mostly in the Galactic disk. Pulsars also present proper motions that are on average much larger than those of stars (velocities are 100 times the Earth’s escape velocity!). Evolution of 100 pulsars in the Galactic gravitational field over 200 Myr. ...
... They are Galactic radio sources, as they are found mostly in the Galactic disk. Pulsars also present proper motions that are on average much larger than those of stars (velocities are 100 times the Earth’s escape velocity!). Evolution of 100 pulsars in the Galactic gravitational field over 200 Myr. ...
Direct Imaging Searches Around White Dwarfs - X
... A dozen WDs are known to be surrounded by dust disks Disks identified as near-IR and mid-IR excesses, 500oK < T < 1200oK Disks within a few solar radii of the WDs Material within the disks is being accreted onto the WD atmosphere – Finally explains WDs with metal-polluted atmospheres ...
... A dozen WDs are known to be surrounded by dust disks Disks identified as near-IR and mid-IR excesses, 500oK < T < 1200oK Disks within a few solar radii of the WDs Material within the disks is being accreted onto the WD atmosphere – Finally explains WDs with metal-polluted atmospheres ...
Observed Properties of Exoplanets: Masses, Orbits, and Metallicities
... leading to predicted growth times of 5–10 Myr. This growth time scale is uncomfortably longer than the observed ∼3 Myr lifetime of the disks themselves.31), 32) Therefore the original core accretion model suffers from a planet-growth rate that is too slow. This inadequacy in the core-accretion model ...
... leading to predicted growth times of 5–10 Myr. This growth time scale is uncomfortably longer than the observed ∼3 Myr lifetime of the disks themselves.31), 32) Therefore the original core accretion model suffers from a planet-growth rate that is too slow. This inadequacy in the core-accretion model ...
Three newly discovered sub-Jupiter-mass planets: WASP
... The WASP data were processed and searched for transit signals as described in Collier Cameron et al. (2006), and the candidate selection process was performed as described in Collier Cameron et al. (2007). We perform a search for transits on each season of data from each camera separately and we per ...
... The WASP data were processed and searched for transit signals as described in Collier Cameron et al. (2006), and the candidate selection process was performed as described in Collier Cameron et al. (2007). We perform a search for transits on each season of data from each camera separately and we per ...
space telescope imaging spectrograph survey of far
... and an absolute wavelength calibration compared with using the Chandra or XMM-Newton grating spectrometers to observe permitted transitions of the same ion stages in the kilovolt X-ray region. Fe xii 1242, 1349 (T 2 106 K) and Fe xxi 1354 (107 K) are well known from solar studies and have bee ...
... and an absolute wavelength calibration compared with using the Chandra or XMM-Newton grating spectrometers to observe permitted transitions of the same ion stages in the kilovolt X-ray region. Fe xii 1242, 1349 (T 2 106 K) and Fe xxi 1354 (107 K) are well known from solar studies and have bee ...
On the elemental abundance and isotopic mixture of mercury in
... strengths as well as uncertainties in the abundance determinations. Also, typical application of the method assumes that all elements are subjected to the same microturbulence and that its value is constant with atmospheric depth. For HgMn stars the ξt parameter is typically found to have small valu ...
... strengths as well as uncertainties in the abundance determinations. Also, typical application of the method assumes that all elements are subjected to the same microturbulence and that its value is constant with atmospheric depth. For HgMn stars the ξt parameter is typically found to have small valu ...
The Life and Work of Edward Emerson Barnard
... the particles making it up. T h e condensations, however, continued to perplex him for some time. The Earth made its second passage through the ring-plane on October 4,1907. With precautions such as using a hexagonal diaphragm over the object glass to collect the stray light into six rays, leaving c ...
... the particles making it up. T h e condensations, however, continued to perplex him for some time. The Earth made its second passage through the ring-plane on October 4,1907. With precautions such as using a hexagonal diaphragm over the object glass to collect the stray light into six rays, leaving c ...
2011-GravLens
... Gravitational lenses can be used as gravitational telescopes. The concentrated light from objects seen behind gravitational lenses makes very faint objects appear brighter, larger and therefore more easily studied. One of the most distant object in the universe was discovered by the gravitational le ...
... Gravitational lenses can be used as gravitational telescopes. The concentrated light from objects seen behind gravitational lenses makes very faint objects appear brighter, larger and therefore more easily studied. One of the most distant object in the universe was discovered by the gravitational le ...
Multiwavelength observations of XTE J1118+480`s outburst
... Spectra typical of neutron stars No radio emission 85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2 X-ray absorption >> IR => absorbing matter local to neutron star NH variation on short periods? => link with accretion column/geometry? ...
... Spectra typical of neutron stars No radio emission 85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2 X-ray absorption >> IR => absorbing matter local to neutron star NH variation on short periods? => link with accretion column/geometry? ...
betelgeuse and the red supergiants
... it will end as a core-collapse supernova leaving a neutron star or black hole. But do we know that it is? If Betelgeuse were to be a lower-mass super-Asymptotic Giant Branch (super-AGB) star it would end up as an electron-capture supernova or die a less spectacular death leaving behind an oxygen-neo ...
... it will end as a core-collapse supernova leaving a neutron star or black hole. But do we know that it is? If Betelgeuse were to be a lower-mass super-Asymptotic Giant Branch (super-AGB) star it would end up as an electron-capture supernova or die a less spectacular death leaving behind an oxygen-neo ...
Star formation
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as ""stellar nurseries"" or ""star-forming regions"", collapse to form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.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.