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 ...
... 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 ...
1 The Hubble Story (10:56)
... dust disks, dubbed proplyds, around the newly born stars in the Orion Nebula. The proplyds may very well be young planetary systems in the early stages of creation. The details revealed by Hubble are superior to anything seen to date with groundbased instruments and, thanks to Hubble, we have visual ...
... dust disks, dubbed proplyds, around the newly born stars in the Orion Nebula. The proplyds may very well be young planetary systems in the early stages of creation. The details revealed by Hubble are superior to anything seen to date with groundbased instruments and, thanks to Hubble, we have visual ...
Chapter 10 Formation and evolution of the Local Group
... The orbits are traced from z = 1 (near each label) to their present position (black dots). The close passage of NGC 6822 is clearly indicated. The orbit of the Large Magellanic Cloud (LMC) is shown, but the Small Magellanic Cloud is excluded from the model since it may interacting with the LMC. Leo ...
... The orbits are traced from z = 1 (near each label) to their present position (black dots). The close passage of NGC 6822 is clearly indicated. The orbit of the Large Magellanic Cloud (LMC) is shown, but the Small Magellanic Cloud is excluded from the model since it may interacting with the LMC. Leo ...
lecture course
... low brightnesses at their centres and absolute B magnitudes fainter than about -18. The faintest galaxies known are dwarf ellipticals. Elliptical galaxies are featureless, with brightness profiles that are high in the centre and lower far away from the centre. Spiral galaxies like the Milky Way and ...
... low brightnesses at their centres and absolute B magnitudes fainter than about -18. The faintest galaxies known are dwarf ellipticals. Elliptical galaxies are featureless, with brightness profiles that are high in the centre and lower far away from the centre. Spiral galaxies like the Milky Way and ...
Evidence for the Tidal Destruction of Hot Jupiters by Subgiant Stars
... Tidal transfer of angular momentum is expected to cause hot Jupiters to spiral into their host stars. Although the timescale for orbital decay is very uncertain, it should be faster for systems with larger and more evolved stars. Indeed, it is well established that hot Jupiters are found less freque ...
... Tidal transfer of angular momentum is expected to cause hot Jupiters to spiral into their host stars. Although the timescale for orbital decay is very uncertain, it should be faster for systems with larger and more evolved stars. Indeed, it is well established that hot Jupiters are found less freque ...
The Ages of Stars
... arrive at an understanding of a process. Some examples include: • The formation and evolution of proto-planetary disks appear to occur in the first ∼ 100 Myr of a star’s life, with debris disks forming later. At present we can just barely limit this time-scale with the methods available, but clearly ...
... arrive at an understanding of a process. Some examples include: • The formation and evolution of proto-planetary disks appear to occur in the first ∼ 100 Myr of a star’s life, with debris disks forming later. At present we can just barely limit this time-scale with the methods available, but clearly ...
The physics of star formation
... Star formation occurs as a result of the action of gravity on a wide range of scales, and different mechanisms may be important on different scales, depending on the forces opposing gravity. On galactic scales, the tendency of interstellar matter to condense under gravity into star-forming clouds is ...
... Star formation occurs as a result of the action of gravity on a wide range of scales, and different mechanisms may be important on different scales, depending on the forces opposing gravity. On galactic scales, the tendency of interstellar matter to condense under gravity into star-forming clouds is ...
Chemical analysis of 24 dusty (pre-) main
... Despite the broad wavelength coverage, for several program stars only a few lines turned out to be appropriate for detailed abundance analyses. Such a circumstance is not unusual for A/B-type stars, where the condition that spectral lines with equivalent widths higher than 150 mÅ should be avoided i ...
... Despite the broad wavelength coverage, for several program stars only a few lines turned out to be appropriate for detailed abundance analyses. Such a circumstance is not unusual for A/B-type stars, where the condition that spectral lines with equivalent widths higher than 150 mÅ should be avoided i ...
solon irving bailey - National Academy of Sciences
... A vivid description of this project is given in Harvard Annals 39, the first volume of the Peruvian Meteorology. After Professor Bailey and his party had passed eight consecutive days and nights at altitudes from 13,000 to 19,000 feet, urging, threatening, rewarding the Indians who shoveled the trai ...
... A vivid description of this project is given in Harvard Annals 39, the first volume of the Peruvian Meteorology. After Professor Bailey and his party had passed eight consecutive days and nights at altitudes from 13,000 to 19,000 feet, urging, threatening, rewarding the Indians who shoveled the trai ...
here - Ira-Inaf
... The far infrared emissivity of the dust in the interstellar medium of the far outer Galaxy is smaller, and the pressure of the intercloud medium is much smaller (Brand and Wouterloot, 1996). Although these factors might be expected to negatively influence the cloud- and star-formation activity in th ...
... The far infrared emissivity of the dust in the interstellar medium of the far outer Galaxy is smaller, and the pressure of the intercloud medium is much smaller (Brand and Wouterloot, 1996). Although these factors might be expected to negatively influence the cloud- and star-formation activity in th ...
chapter 15 navigational astronomy
... The principal bodies orbiting the Sun are called planets. Nine principal planets are known: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Of these, only four are commonly used for celestial navigation: Venus, Mars, Jupiter, and Saturn. Except for Pluto, the orbits of the ...
... The principal bodies orbiting the Sun are called planets. Nine principal planets are known: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Of these, only four are commonly used for celestial navigation: Venus, Mars, Jupiter, and Saturn. Except for Pluto, the orbits of the ...
The science case for - Astrophysics
... extrasolar planets, gamma ray bursts, the cosmic microwave background, dark matter and dark energy have all been discovered through the development of a succession of ever larger and more sophisticated telescopes. In the last decade, satellite observatories and the new generation of 8- to 10-metre d ...
... extrasolar planets, gamma ray bursts, the cosmic microwave background, dark matter and dark energy have all been discovered through the development of a succession of ever larger and more sophisticated telescopes. In the last decade, satellite observatories and the new generation of 8- to 10-metre d ...
Mission Possible: Voyage to the Stars
... All stars are created from a nebula but where they go after that depends on their mass. All aspects of a star including size, temperature, life history, and luminosity are determined by the original mass of the star. The HertzsprungRussell diagram is a diagram that is used by astronomers to classify ...
... All stars are created from a nebula but where they go after that depends on their mass. All aspects of a star including size, temperature, life history, and luminosity are determined by the original mass of the star. The HertzsprungRussell diagram is a diagram that is used by astronomers to classify ...
The white dwarf population within 40 pc of the Sun
... For each of the synthetic white dwarf populations described below, we generated 50 independent Monte Carlo simulations employing different initial seeds. Furthermore, for each of these Monte Carlo realizations, we increased the number of simulated Monte Carlo realizations to 104 using bootstrap tech ...
... For each of the synthetic white dwarf populations described below, we generated 50 independent Monte Carlo simulations employing different initial seeds. Furthermore, for each of these Monte Carlo realizations, we increased the number of simulated Monte Carlo realizations to 104 using bootstrap tech ...
Hot subdwarf stars-galactic orbits and distribution perpendicular to
... Hot subdwarfs are blue, horizontal-branch like stars, representing the late stages of evolution of stars having started with less than about 2.5 M⊙ on the main sequence. The hotter subdwarf B (sdB) stars form a well defined group. Their luminosity is of the order of 10 L⊙ and their surface temperatu ...
... Hot subdwarfs are blue, horizontal-branch like stars, representing the late stages of evolution of stars having started with less than about 2.5 M⊙ on the main sequence. The hotter subdwarf B (sdB) stars form a well defined group. Their luminosity is of the order of 10 L⊙ and their surface temperatu ...
The Kuiper Belt Explored by Serendipitous Stellar Occultations
... The characteristic scale of the Fresnel diffraction effect (i.e., roughly speaking, the broadening of the object shadow) is the so-called Fresnel scale Fs = (λD/2) (Warner, 1988). [Note that some authors give different definitions for the Fresnel scale: (λD/2π) , (λD) , or (λD)/2 .] The Fresnel scal ...
... The characteristic scale of the Fresnel diffraction effect (i.e., roughly speaking, the broadening of the object shadow) is the so-called Fresnel scale Fs = (λD/2) (Warner, 1988). [Note that some authors give different definitions for the Fresnel scale: (λD/2π) , (λD) , or (λD)/2 .] The Fresnel scal ...
Sparse aperture masking at the VLT II. Detection limits for the eight
... HD181327 and HR8799) with SAM technique on the NaCo instrument at the VLT. Results. No close companions were detected using closure phase information under 0.500 of separation from the parent stars. We obtained magnitude detection limits that we converted to Jupiter masses detection limits using the ...
... HD181327 and HR8799) with SAM technique on the NaCo instrument at the VLT. Results. No close companions were detected using closure phase information under 0.500 of separation from the parent stars. We obtained magnitude detection limits that we converted to Jupiter masses detection limits using the ...
LCM Analysis for PLATO 2.0
... The confrontation between the evolution of the O’Connell effect and the maxima separiation may produce three results: 1) no correlation (no spot activity at all), 2) horizontally flattened circle (starspot migration) and 3) vertical distribution. The last one is particularly interesting, since it im ...
... The confrontation between the evolution of the O’Connell effect and the maxima separiation may produce three results: 1) no correlation (no spot activity at all), 2) horizontally flattened circle (starspot migration) and 3) vertical distribution. The last one is particularly interesting, since it im ...
Perseus (constellation)
Perseus, named after the Greek mythological hero Perseus, is a constellation in the northern sky. It was one of 48 listed by the 2nd-century astronomer Ptolemy and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located in the northern celestial hemisphere near several other constellations named after legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west.The galactic plane of the Milky Way passes through Perseus but is mostly obscured by molecular clouds. The constellation's brightest star is the yellow-white supergiant Alpha Persei (also called Mirfak), which shines at magnitude 1.79. It and many of the surrounding stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol (Beta Persei), linked with ominous legends because of its variability, which is noticeable to the naked eye. Rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a binary system containing a neutron star, and GK Persei, a nova that peaked at magnitude 0.2 in 1901. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese. The constellation gives its name to the Perseus Cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth. It hosts the radiant of the annual Perseids meteor shower—one of the most prominent meteor showers in the sky.