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... 1999: using ASCA, X-1 in M82 was found to vary by up to a factor of four, confirming that this bright source was indeed a single object. *Over half of ULXs are known to be variable, ruling out the multiple source or SNR hypothesis. ...
... 1999: using ASCA, X-1 in M82 was found to vary by up to a factor of four, confirming that this bright source was indeed a single object. *Over half of ULXs are known to be variable, ruling out the multiple source or SNR hypothesis. ...
A prevalence of dynamo-generated magnetic fields in the
... separated by the so-called large frequency separation, ∆ν. One of these overtone sequences is seen for each spherical degree, !. For observations of unresolved distant stars, geometric cancellation prevents the detection of modes with ! > 3. Their spectra are characterized by a pattern of radial (! ...
... separated by the so-called large frequency separation, ∆ν. One of these overtone sequences is seen for each spherical degree, !. For observations of unresolved distant stars, geometric cancellation prevents the detection of modes with ! > 3. Their spectra are characterized by a pattern of radial (! ...
To Measure the Sky: An Introduction to Observational Astronomy.
... Instead of the altitude, astronomers sometimes use its complement, z, the zenith distance (:TOP in the figure). The (a, e) coordinates of an object clearly describe where it is located in an observer’s sky. You can readily imagine an instrument that would measure these coordinates: a telescope or oth ...
... Instead of the altitude, astronomers sometimes use its complement, z, the zenith distance (:TOP in the figure). The (a, e) coordinates of an object clearly describe where it is located in an observer’s sky. You can readily imagine an instrument that would measure these coordinates: a telescope or oth ...
The Time of Day
... round, the Sun can’t be “overhead” everywhere at the same time, so it can’t be noon everywhere at the same time. By the late 1800s, with the increasing speed of travel and communications, it became confusing for each city to maintain its own time according to the position of the Sun in the sky. By i ...
... round, the Sun can’t be “overhead” everywhere at the same time, so it can’t be noon everywhere at the same time. By the late 1800s, with the increasing speed of travel and communications, it became confusing for each city to maintain its own time according to the position of the Sun in the sky. By i ...
arXiv:astro-ph/0508448v1 22 Aug 2005
... notable that, in all five of the Galactic WC+O systems with measured masses, the WC star (which is a stripped core nearing the very end of its lifetime) is more massive than 8 M⊙ . These systems also have massive O star companions (23 – 34 M⊙ , van der Hucht 2001) which will quite probably still be ...
... notable that, in all five of the Galactic WC+O systems with measured masses, the WC star (which is a stripped core nearing the very end of its lifetime) is more massive than 8 M⊙ . These systems also have massive O star companions (23 – 34 M⊙ , van der Hucht 2001) which will quite probably still be ...
No. 2 - Society for Astronomical Sciences
... The small-telescope research community has long needed an all-sky network of photometric “secondary standard” stars. Such a network will be a boon to both variable-star and asteroid studies. Tom Smith described the equipment, procedures, and progress of the APASS (AAVSO Photometric All-Sky Survey). ...
... The small-telescope research community has long needed an all-sky network of photometric “secondary standard” stars. Such a network will be a boon to both variable-star and asteroid studies. Tom Smith described the equipment, procedures, and progress of the APASS (AAVSO Photometric All-Sky Survey). ...
The Galactic Halo The Galactic Disk Height and Thickness of MW
... Shapley’s Center of the Galaxy " To find the center of the Galaxy, Shapley measured the distance to each cluster using RR Lyrae stars and produced a three dimensional plot of the clusters’ positions. The center of the Galaxy was then identified by the average position of the clusters. " We now know ...
... Shapley’s Center of the Galaxy " To find the center of the Galaxy, Shapley measured the distance to each cluster using RR Lyrae stars and produced a three dimensional plot of the clusters’ positions. The center of the Galaxy was then identified by the average position of the clusters. " We now know ...
Chemical Evolution
... populations in components predicted to be predominantly formed in mergers: stellar halo, thick disk, bulge For the Milky Way, dominantly OLD, seems to have been rather quiescent since z ~ 2; atypical in CDM? M31 more violent history? (A. Ferguson et al 2002; Brown et al 03) M33 more quiet – is ...
... populations in components predicted to be predominantly formed in mergers: stellar halo, thick disk, bulge For the Milky Way, dominantly OLD, seems to have been rather quiescent since z ~ 2; atypical in CDM? M31 more violent history? (A. Ferguson et al 2002; Brown et al 03) M33 more quiet – is ...
STAR ANALYSER 100 USER MANUAL PATON HAWKSLEY EDUCATION LTD
... means that a much higher proportion of the light is directed into the spectrum compared with lower cost unblazed or holographic film gratings for example, allowing far fainter objects to be recorded. It is physically identical to a standard 1 1/4 inch filter. This means it can be screwed onto a stan ...
... means that a much higher proportion of the light is directed into the spectrum compared with lower cost unblazed or holographic film gratings for example, allowing far fainter objects to be recorded. It is physically identical to a standard 1 1/4 inch filter. This means it can be screwed onto a stan ...
Stars and Galaxies
... band of stars that appears on plots of stellar color versus brightness ) Nuclear Fusion reactions (2 atoms jammed togetherenergy emitted as light and heat)- converts 600,000,000 tons of hydrogen into helium every second Many thousands of times closer to Earth than any other star A planet’s charac ...
... band of stars that appears on plots of stellar color versus brightness ) Nuclear Fusion reactions (2 atoms jammed togetherenergy emitted as light and heat)- converts 600,000,000 tons of hydrogen into helium every second Many thousands of times closer to Earth than any other star A planet’s charac ...
How to Build an Astrolabe
... Greece, were extensively developed in the medieval Islamic world and became the key astronomical instrument of the western middle ages. When mapping the heavens astronomers assume that the stars seen in the night sky are all at an equal distance from the earth, fixed on the inside of an enormous sph ...
... Greece, were extensively developed in the medieval Islamic world and became the key astronomical instrument of the western middle ages. When mapping the heavens astronomers assume that the stars seen in the night sky are all at an equal distance from the earth, fixed on the inside of an enormous sph ...
How to Build an Astrolabe - St John`s College, Cambridge
... Greece, were extensively developed in the medieval Islamic world and became the key astronomical instrument of the western middle ages. When mapping the heavens astronomers assume that the stars seen in the night sky are all at an equal distance from the earth, fixed on the inside of an enormous sph ...
... Greece, were extensively developed in the medieval Islamic world and became the key astronomical instrument of the western middle ages. When mapping the heavens astronomers assume that the stars seen in the night sky are all at an equal distance from the earth, fixed on the inside of an enormous sph ...
Statistical analysis of stellar evolution
... separate out groups of stars powered by different physical processes and at different stages of their lives. These groups include the main sequence, so named for its dominant position in a CMD, the evolved red giants, and the even older white dwarfs. Today the physical processes that govern stellar ...
... separate out groups of stars powered by different physical processes and at different stages of their lives. These groups include the main sequence, so named for its dominant position in a CMD, the evolved red giants, and the even older white dwarfs. Today the physical processes that govern stellar ...
Ursa Minor
Ursa Minor (Latin: ""Smaller She-Bear"", contrasting with Ursa Major), also known as the Little Bear, is a constellation in the northern sky. Like the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, hence the name Little Dipper. It was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Ursa Minor has traditionally been important for navigation, particularly by mariners, due to Polaris being the North Star.Polaris, the brightest star in the constellation, is a yellow-white supergiant and the brightest Cepheid variable star in the night sky, ranging from apparent magnitude 1.97 to 2.00. Beta Ursae Minoris, also known as Kochab, is an aging star that has swollen and cooled to become an orange giant with an apparent magnitude of 2.08, only slightly fainter than Polaris. Kochab and magnitude 3 Gamma Ursae Minoris have been called the ""guardians of the pole star"". Planets have been detected orbiting four of the stars, including Kochab. The constellation also contains an isolated neutron star—Calvera—and H1504+65, the hottest white dwarf yet discovered with a surface temperature of 200,000 K.