PPT - Chandra X-Ray Observatory
... white dwarfs • Hydrogen in hot DAs almost completely ionized, EUV/soft X-ray opacity strongly reduced → DAs with Teff >30,000 K can emit thermal soft X-rays from deep hot layers • However, ROSAT All-Sky Survey revealed that X-ray emission is the exception rather than the rule → additional absorbers ...
... white dwarfs • Hydrogen in hot DAs almost completely ionized, EUV/soft X-ray opacity strongly reduced → DAs with Teff >30,000 K can emit thermal soft X-rays from deep hot layers • However, ROSAT All-Sky Survey revealed that X-ray emission is the exception rather than the rule → additional absorbers ...
Exploring and Observing the Sun and Stars
... cotton swabs (see Advance Preparation, 1 per student) crayons or colored pencils (per group) drawings – from previous activity (of constellations by students) egg cartons (Styrofoam™, see Advance Preparation, per group) flashlights (for demonstration, 2 per class) paint (glow-in-the-dark, see Advanc ...
... cotton swabs (see Advance Preparation, 1 per student) crayons or colored pencils (per group) drawings – from previous activity (of constellations by students) egg cartons (Styrofoam™, see Advance Preparation, per group) flashlights (for demonstration, 2 per class) paint (glow-in-the-dark, see Advanc ...
On the Frequency of Giant Planets in the Metal
... –transits by rocky planets can be detected with relatively modest precision –transiting objects will have short periods but will lie in the habitable zone –the flux contrast ratio is much more favorable for direct spectroscopic investigation of the secondary eclipse •May require the development of p ...
... –transits by rocky planets can be detected with relatively modest precision –transiting objects will have short periods but will lie in the habitable zone –the flux contrast ratio is much more favorable for direct spectroscopic investigation of the secondary eclipse •May require the development of p ...
The Milky Way - National Tsing Hua University
... making new stars as the eons pass, but the nuclei of some galaxies are sites of powerful eruptions that eject highspeed jets in opposite directions. As you study these active galaxies, you will be combining many of the ideas you have discovered so far to answer five essential questions: • What evide ...
... making new stars as the eons pass, but the nuclei of some galaxies are sites of powerful eruptions that eject highspeed jets in opposite directions. As you study these active galaxies, you will be combining many of the ideas you have discovered so far to answer five essential questions: • What evide ...
here - HKU Physics
... envelope of a so-called post AGB star finally gets gracefully expelled at 20-35km/s and the remnant core star (on its way to becoming a so-called white-dwarf) heats up and generates an ionizing radiation field. The UV radiation causes the ejected gas to glow with a rich emission line spectrum that l ...
... envelope of a so-called post AGB star finally gets gracefully expelled at 20-35km/s and the remnant core star (on its way to becoming a so-called white-dwarf) heats up and generates an ionizing radiation field. The UV radiation causes the ejected gas to glow with a rich emission line spectrum that l ...
The physics of white dwarfs
... of stellar evolution. Their properties thus provide clues to the physical processes that take place during the rapid and often spectacular evolutionary stages near the ends of stellar lifetimes. In addition, white dwarfs provide astrophysical "laboratories" for "measuring" the physical properties of ...
... of stellar evolution. Their properties thus provide clues to the physical processes that take place during the rapid and often spectacular evolutionary stages near the ends of stellar lifetimes. In addition, white dwarfs provide astrophysical "laboratories" for "measuring" the physical properties of ...
Astronomers discovered what they thought was the first black hole
... and his colleagues say the system was born between 8.7 and 11.4 million years ago with two massive stars orbiting each other. The more massive star – the one that is now the black hole – was born at least 110 times heavier than the Sun, making it one of the most luminous stars in the galaxy. Its par ...
... and his colleagues say the system was born between 8.7 and 11.4 million years ago with two massive stars orbiting each other. The more massive star – the one that is now the black hole – was born at least 110 times heavier than the Sun, making it one of the most luminous stars in the galaxy. Its par ...
Module 11.1.1: Galaxies: Morphology and the Hubble Sequence
... [slide 9] Now, between elliptical and spiral galaxies Hubble introduced the intermediate type S0's, which are galaxies that obviously had a disk but he couldn't see any spiral arms. Here's Som ...
... [slide 9] Now, between elliptical and spiral galaxies Hubble introduced the intermediate type S0's, which are galaxies that obviously had a disk but he couldn't see any spiral arms. Here's Som ...
Stellar Spectroscopy
... a function of wavelength. In the diagram above the three types of spectra are shown. In the bottom frame they are shown together, as they might appear in an object’s spectrum. ...
... a function of wavelength. In the diagram above the three types of spectra are shown. In the bottom frame they are shown together, as they might appear in an object’s spectrum. ...
ACTIVE GALAXIES
... • About 1% of all Spirals are SEYFERTS, so • Either 1% of all S's are always Seyferts OR • 100% of S's are Seyferts for about 1% of the time ...
... • About 1% of all Spirals are SEYFERTS, so • Either 1% of all S's are always Seyferts OR • 100% of S's are Seyferts for about 1% of the time ...
Parallel Programs
... Then the state of the variables is updated, based on this solution. Then the equations of motion are solved for the next time-step. Each time-step consists of several computational phases. • Values are set up. • A system of equations is solved. All phases sweep through all points of the arrays and m ...
... Then the state of the variables is updated, based on this solution. Then the equations of motion are solved for the next time-step. Each time-step consists of several computational phases. • Values are set up. • A system of equations is solved. All phases sweep through all points of the arrays and m ...
Weakened magnetic braking as the origin of anomalously
... for uncertainties in the ages, masses, and compositions (see Methods) and predict the rotation periods that we should have observed given existing period–age relations2,14 (Pexpected), we find that the systematic offset persists; stars of roughly solar age and older are rotating more rapidly than pr ...
... for uncertainties in the ages, masses, and compositions (see Methods) and predict the rotation periods that we should have observed given existing period–age relations2,14 (Pexpected), we find that the systematic offset persists; stars of roughly solar age and older are rotating more rapidly than pr ...
ppt - NRAO
... E.g.: Taurus (of course), Orion is much larger than the Orion Nebula, It is not clear if all of Perseus is at the same distance (NGC1333 vs. IC 348), Ophiuchus streamers, etc.. (Note that these regions tend to be heavily obscured, so optical experiments are unlikely to improve significantly the situ ...
... E.g.: Taurus (of course), Orion is much larger than the Orion Nebula, It is not clear if all of Perseus is at the same distance (NGC1333 vs. IC 348), Ophiuchus streamers, etc.. (Note that these regions tend to be heavily obscured, so optical experiments are unlikely to improve significantly the situ ...
Identifying Young far from Giant Stars Molecular Clouds
... It is speculated that classical T Tauri stars evolve into weak T Tauri stars, their accretion disks gradually dissipating over time (Walter et al. 1988). The two types of stars are similar in luminosities and effective temperature, implying a potential evolutionary relationship. The dust and gas wit ...
... It is speculated that classical T Tauri stars evolve into weak T Tauri stars, their accretion disks gradually dissipating over time (Walter et al. 1988). The two types of stars are similar in luminosities and effective temperature, implying a potential evolutionary relationship. The dust and gas wit ...
Observations of Near Infrared Extragalactic Background (NIR_EBL)
... 1. Small neutral fractions at z ~ 6 (1% neutral) 2. Sharp transition at z~6 (end of reionization?) ...
... 1. Small neutral fractions at z ~ 6 (1% neutral) 2. Sharp transition at z~6 (end of reionization?) ...
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.