Astro 7B – Solution Set 7 1 A Star is Born
... medium. Assume the temperature of the cloud is such that the cloud is initially marginally Jeans-unstable. The gas consists predominantly of molecular hydrogen. As the cloud collapses inward, its density increases. In the absence of cooling mechanisms, the gas will heat adiabatically (gravitational ...
... medium. Assume the temperature of the cloud is such that the cloud is initially marginally Jeans-unstable. The gas consists predominantly of molecular hydrogen. As the cloud collapses inward, its density increases. In the absence of cooling mechanisms, the gas will heat adiabatically (gravitational ...
Binary Star Systems
... – Sufficiently close to Earth and the stars are well enough separated that we can see the two stars individually (resolved) in a telescope and track their motion over a period of time ...
... – Sufficiently close to Earth and the stars are well enough separated that we can see the two stars individually (resolved) in a telescope and track their motion over a period of time ...
Object A
... Feb. 29 – Last day to drop with an automatic “W” Apr. 1 – Last day to drop a class with W, F, FA ...
... Feb. 29 – Last day to drop with an automatic “W” Apr. 1 – Last day to drop a class with W, F, FA ...
Chapter 4 On the possibility of a helium white dwarf donor in the
... Second, it has an X-ray luminosity which is low for an active LMXB, namely less than or equal to 1% of the Eddington limit for a canonical (1.4 M⊙ , 10 km radius) neutron star (Jonker et al. 2001). Third, 2S 0918–549 appears to have an unusually high Ne/O abundance ratio, a characteristic which it s ...
... Second, it has an X-ray luminosity which is low for an active LMXB, namely less than or equal to 1% of the Eddington limit for a canonical (1.4 M⊙ , 10 km radius) neutron star (Jonker et al. 2001). Third, 2S 0918–549 appears to have an unusually high Ne/O abundance ratio, a characteristic which it s ...
The accretion properties of the intermediate mass Herbig Ae/Be stars
... § Herbig Ae/Be stars bridge the gap between low and high mass young stars and cover the mass where transition in accretion mode occurs. § Conducted largest spectral survey – 0.4 – 2.4 micron spectra of 90 objects § Determined spectral types, temperatures, radii, reddening in a homogeneous manner ...
... § Herbig Ae/Be stars bridge the gap between low and high mass young stars and cover the mass where transition in accretion mode occurs. § Conducted largest spectral survey – 0.4 – 2.4 micron spectra of 90 objects § Determined spectral types, temperatures, radii, reddening in a homogeneous manner ...
Research Powerpoint - Department of Astronomy
... coming from asteroid 596 Scheila after it was hit by another asteroid. On the right, comet Lulin, seen with Swift’s Xray (red) and UV (blue) telescopes. Comets glow in X-ray when the solar wind flows through the neutral gas (as seen here in UV). ...
... coming from asteroid 596 Scheila after it was hit by another asteroid. On the right, comet Lulin, seen with Swift’s Xray (red) and UV (blue) telescopes. Comets glow in X-ray when the solar wind flows through the neutral gas (as seen here in UV). ...
Lecture 12
... • Types of binary stars – Visual – Spectroscopic – Eclipsing • Only way to measure stellar masses: – Only ~150 stars ...
... • Types of binary stars – Visual – Spectroscopic – Eclipsing • Only way to measure stellar masses: – Only ~150 stars ...
TWO NEW VARIABLE STARS OBSERVED IN THE FIELD OF THE
... Only on the base of our photometric data some doubts necessairly remain regarding the precise identity of the system, and we considered here two plausible alternatives. The object could be a short-period non eclipsing binary system showing the properties typical of an ellipsoidal variable (ELL varia ...
... Only on the base of our photometric data some doubts necessairly remain regarding the precise identity of the system, and we considered here two plausible alternatives. The object could be a short-period non eclipsing binary system showing the properties typical of an ellipsoidal variable (ELL varia ...
THE GALACTIC GAZETTE The Astronomical Society of Southern New England Next Meeting
... nuclear fuel faster, so they run out before their smaller, more miserly brethren. When that happens the core of the star contracts and heats up, and the outer layers respond by inflating hugely, like a hot air balloon. The heat from the interior gets spread out through the much ...
... nuclear fuel faster, so they run out before their smaller, more miserly brethren. When that happens the core of the star contracts and heats up, and the outer layers respond by inflating hugely, like a hot air balloon. The heat from the interior gets spread out through the much ...
A new isolated dSph galaxy near the Local Group
... We determine the quantitative star formation and metal enrichment history of KKs 3 from the CMD using our STARPROBE program. The program develops an approximation to the observed distribution of stars in the CMD using a positive linear combination of synthetic diagrams formed by simple stellar popul ...
... We determine the quantitative star formation and metal enrichment history of KKs 3 from the CMD using our STARPROBE program. The program develops an approximation to the observed distribution of stars in the CMD using a positive linear combination of synthetic diagrams formed by simple stellar popul ...
Lecture 5: The Milky Way
... Tangential orbital speed V (km/sec) Thin-disc stars follow nearly circular orbits, with most of their motion being tangential. Halo stars are equally likely to follow prograde or retrograde orbits and cross the midplane with high speeds. ...
... Tangential orbital speed V (km/sec) Thin-disc stars follow nearly circular orbits, with most of their motion being tangential. Halo stars are equally likely to follow prograde or retrograde orbits and cross the midplane with high speeds. ...
My power point presentation on spectroscopy of stars (ppt file)
... the open cluster NGC 2516 • This star shows strong Zeeman splitting in almost every spectral line, due to a magnetic field of 14.5 kG (1.45 Tesla) • The trace elements in the atmosphere are stratified vertically and horizontally patchy. I have not included enough of these effects in my model to repr ...
... the open cluster NGC 2516 • This star shows strong Zeeman splitting in almost every spectral line, due to a magnetic field of 14.5 kG (1.45 Tesla) • The trace elements in the atmosphere are stratified vertically and horizontally patchy. I have not included enough of these effects in my model to repr ...
Introduction to Basic Stargazing Part I - Naples Free-Net
... With a calendar, you can have reliable agriculture, which is the basis of civilization. Take your star chart and look for the constellation Hercules, just for an example. You will note that the constellation Hercules as drawn does not look much like a man; constellations only occasionally look like ...
... With a calendar, you can have reliable agriculture, which is the basis of civilization. Take your star chart and look for the constellation Hercules, just for an example. You will note that the constellation Hercules as drawn does not look much like a man; constellations only occasionally look like ...
Connecting Stars, Galaxies and the Universe
... Once such calibrations have been determined, single stars can be used to determine the details of the assembly history of our Milky Way. Preliminary work on the formation of the thin disk has been done with Hipparcos data (e.g., Binney et al. 2000). However, ages for single stars will be about an or ...
... Once such calibrations have been determined, single stars can be used to determine the details of the assembly history of our Milky Way. Preliminary work on the formation of the thin disk has been done with Hipparcos data (e.g., Binney et al. 2000). However, ages for single stars will be about an or ...
Stellar Mass Assembly History
... • Techniques are now well-established for estimating the stellar masses of galaxies to high redshift; reliability depends on having spectroscopic redshifts and long wavelength data • It is now clear that mass assembly since z~2 does not proceed hierarchically; growth is suppressed in high mass syste ...
... • Techniques are now well-established for estimating the stellar masses of galaxies to high redshift; reliability depends on having spectroscopic redshifts and long wavelength data • It is now clear that mass assembly since z~2 does not proceed hierarchically; growth is suppressed in high mass syste ...
Astr. 170B1 Due Feb. 5 Professor Rieke and TA Melissa Halford
... 10. Hydrogen has a spectral line that is observed at a wavelength of 656 nm (656x10‐9 meters). Recalling that the speed of light is c = 3x108 meters/sec and the relationship between wavelength and frequency, frequency = c/wavelength, what is the frequency of the photons observed as this spectra ...
... 10. Hydrogen has a spectral line that is observed at a wavelength of 656 nm (656x10‐9 meters). Recalling that the speed of light is c = 3x108 meters/sec and the relationship between wavelength and frequency, frequency = c/wavelength, what is the frequency of the photons observed as this spectra ...
L103 A NEW MILKY WAY DWARF SATELLITE IN CANES
... ascension and declination, measured in degrees. The dotted circle indicates a radius of 0⬚. 25. Upper middle: Spatial distribution of all objects classified as stars in the same area. Upper right: Binned spatial density of all stellar objects. The inner dotted circle marks a radius of 0⬚. 25, the mi ...
... ascension and declination, measured in degrees. The dotted circle indicates a radius of 0⬚. 25. Upper middle: Spatial distribution of all objects classified as stars in the same area. Upper right: Binned spatial density of all stellar objects. The inner dotted circle marks a radius of 0⬚. 25, the mi ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.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.