ISA_lecture01 - School of Physics
... Astrophysics has long been one of the driving forces for the advancement of physics in general. It has been closely linked to advances in quantum mechanics and nuclear physics in particular. Stellar astrophysics in particular is also firmly rooted in classical physics - the familiar laws of mechanic ...
... Astrophysics has long been one of the driving forces for the advancement of physics in general. It has been closely linked to advances in quantum mechanics and nuclear physics in particular. Stellar astrophysics in particular is also firmly rooted in classical physics - the familiar laws of mechanic ...
Precision age indicators that exploit chemically peculiar stars
... Tracing stellar population age by integrated light is a mainstay of galaxy evolution interpretation. Somewhat ambiguously, yet still of great value, blue photometric colors generally indicate galaxies with ongoing star formation, while red colors indicate galaxies that have not formed significant nu ...
... Tracing stellar population age by integrated light is a mainstay of galaxy evolution interpretation. Somewhat ambiguously, yet still of great value, blue photometric colors generally indicate galaxies with ongoing star formation, while red colors indicate galaxies that have not formed significant nu ...
The Interstellar Medium White Paper
... clouds that are long-lived and stable, supported against gravity by internal turbulence and magnetic fields. This contrasts strongly with the picture given by mechanism (iv), of compression in converging flows, where gravity plays little role. It produces molecular clouds that are transient features ...
... clouds that are long-lived and stable, supported against gravity by internal turbulence and magnetic fields. This contrasts strongly with the picture given by mechanism (iv), of compression in converging flows, where gravity plays little role. It produces molecular clouds that are transient features ...
Publications 2003 - Département d`Astrophysique, Géophysique et
... He and Si surface inhomogeneities of four Bp variable stars We present ground-based multi-colour Geneva photometry and high-resolution spectra of four variable B-type stars: HD 105382, HD 131120, HD 138769 and HD 55522. All sets of data reveal monoperiodic stars. A comparison of moment variations o ...
... He and Si surface inhomogeneities of four Bp variable stars We present ground-based multi-colour Geneva photometry and high-resolution spectra of four variable B-type stars: HD 105382, HD 131120, HD 138769 and HD 55522. All sets of data reveal monoperiodic stars. A comparison of moment variations o ...
Clusters: age scales for stellar physics
... In order to define an age scale (or several), it is very important to keep in mind that we cannot make experiments except in very few situations and we rely on observations and theory. Thus, observational phenomena with very well defined ages, our anchors, are extremely important. As a matter of fac ...
... In order to define an age scale (or several), it is very important to keep in mind that we cannot make experiments except in very few situations and we rely on observations and theory. Thus, observational phenomena with very well defined ages, our anchors, are extremely important. As a matter of fac ...
Galaxies
... e. the stars in the spiral arms emit most of their energy at radio wavelengths. If the spiral density wave were the only thing producing spiral arms, it would be expected that a. all spiral arms would be dust free. b. all galaxies would have only two smooth spiral arms. c. the Milky Way would be mor ...
... e. the stars in the spiral arms emit most of their energy at radio wavelengths. If the spiral density wave were the only thing producing spiral arms, it would be expected that a. all spiral arms would be dust free. b. all galaxies would have only two smooth spiral arms. c. the Milky Way would be mor ...
11 The Interstellar Medium
... forming many stars at one time. b) One star forms; other matter goes into planets, moons, asteroids, & comets. c) Clouds rotate & throw off mass until only enough is left to form one star. ...
... forming many stars at one time. b) One star forms; other matter goes into planets, moons, asteroids, & comets. c) Clouds rotate & throw off mass until only enough is left to form one star. ...
The extreme ultraviolet and X-ray Sun in Time: High
... a first approximation, the thermal mass loss rate from a simple hydrogen dominated planetary atmosphere, Ṁpl , can be estimated using the energy limited approach (Watson et al. 1981; Lammer et al. 2009), where Ṁpl is proportional to the incident stellar EUV flux for a given set of planetary parame ...
... a first approximation, the thermal mass loss rate from a simple hydrogen dominated planetary atmosphere, Ṁpl , can be estimated using the energy limited approach (Watson et al. 1981; Lammer et al. 2009), where Ṁpl is proportional to the incident stellar EUV flux for a given set of planetary parame ...
Astrophysics Pristine CNO abundances from Magellanic Cloud B stars
... indicate that it can take place very early on, i.e. whilst on the main sequence (MS). Furthermore, one can expect rotational mixing to be more efficient in metal-poor environments (cf. Maeder & Meynet 2001), as metal-deficient stars have smaller radii for a given mass and thus rotate faster for a gi ...
... indicate that it can take place very early on, i.e. whilst on the main sequence (MS). Furthermore, one can expect rotational mixing to be more efficient in metal-poor environments (cf. Maeder & Meynet 2001), as metal-deficient stars have smaller radii for a given mass and thus rotate faster for a gi ...
Survey of Astrophysics A110 The Milky Way Galaxy
... • A star cluster refers to a region in space in which there is a large concentration of stars. • Two types of clusters: – 1. Open Clusters (sometimes called Galactic Clusters). – 2. Globular Clusters. ...
... • A star cluster refers to a region in space in which there is a large concentration of stars. • Two types of clusters: – 1. Open Clusters (sometimes called Galactic Clusters). – 2. Globular Clusters. ...
Annual report 2004 - Département d`Astrophysique, Géophysique et
... In the framework of a long-term spectroscopic and photometric monitoring of slowly pulsating B stars we studied thoroughly the northern target star HD 147394. We performed an end-to-end analysis, consisting of a frequency analysis, a mode identification from line-profile variations and a comparison ...
... In the framework of a long-term spectroscopic and photometric monitoring of slowly pulsating B stars we studied thoroughly the northern target star HD 147394. We performed an end-to-end analysis, consisting of a frequency analysis, a mode identification from line-profile variations and a comparison ...
arXiv:astro-ph/0701557v1 19 Jan 2007
... We investigate the stellar populations in the star forming ring of the luminous infrared galaxy NGC 7469. We use Hubble Space Telescope multi-wavelength (UV through NIR) imaging complemented with new K-band ground-based long-slit spectroscopy, and mid-IR and radio maps from the literature. Spectral ...
... We investigate the stellar populations in the star forming ring of the luminous infrared galaxy NGC 7469. We use Hubble Space Telescope multi-wavelength (UV through NIR) imaging complemented with new K-band ground-based long-slit spectroscopy, and mid-IR and radio maps from the literature. Spectral ...
... • Galaxies and other objects may have motions that have nothing to do with the expansion of space • When galaxies orbit each other, sometimes their orbital speed is much larger than the redshift caused by expansion. • We cannot use Hubble’s law for nearby galaxies, and certainly not for any objects ...
Teacher`s Guide - Cornell Science Inquiry Partnerships
... having students graph properties of populations of humans based on a “snapshot” in time (i.e., a photograph or a census) and seeing what they can infer about these populations and how they change, the activity seeks to demystify the processes that astronomers and other scientists use. The same techn ...
... having students graph properties of populations of humans based on a “snapshot” in time (i.e., a photograph or a census) and seeing what they can infer about these populations and how they change, the activity seeks to demystify the processes that astronomers and other scientists use. The same techn ...
Chapter 18 - Origin and Evolution of Stars Chapter Preview
... Consider the evolution of a star’s in a cluster as a race, from the initial stage of pre-stellar cloud collapse through main sequence hydrogen fusion to stellar death (Figure 16). In today’s race we have three contestants. In the pole position is the odds on favorite a 10 solar mass star, nicknamed ...
... Consider the evolution of a star’s in a cluster as a race, from the initial stage of pre-stellar cloud collapse through main sequence hydrogen fusion to stellar death (Figure 16). In today’s race we have three contestants. In the pole position is the odds on favorite a 10 solar mass star, nicknamed ...
Ferraro et al. 2006
... This evidence is interpreted as the presence of CNO burning products on the BSS surface coming from a deeply peeled parent star, as expected in the case of mass-transfer formation channel ...
... This evidence is interpreted as the presence of CNO burning products on the BSS surface coming from a deeply peeled parent star, as expected in the case of mass-transfer formation channel ...
Late Summer Messier Objects
... companion Herschel 36 to the WSW, are the primary illuminators of M8, just as star C in the Trapezium is the primary illuminator of M42. Like the Trapezium stars, 9 Sgr and Herschel 36 are O-type stars emitting the great majority of their energy in the ultraviolet spectrum, and causing the hydrogen ...
... companion Herschel 36 to the WSW, are the primary illuminators of M8, just as star C in the Trapezium is the primary illuminator of M42. Like the Trapezium stars, 9 Sgr and Herschel 36 are O-type stars emitting the great majority of their energy in the ultraviolet spectrum, and causing the hydrogen ...
Stellar Masses
... stably. Objects with masses slightly below this limit are called brown dwarfs, and are ‘star like’ in the sense that nuclear burning of deuterium occurs in their core. Below a mass of 0.015M⊙ (roughly 16 times the mass of Jupiter) not even deuterium burning can occur, and these objects are perhaps b ...
... stably. Objects with masses slightly below this limit are called brown dwarfs, and are ‘star like’ in the sense that nuclear burning of deuterium occurs in their core. Below a mass of 0.015M⊙ (roughly 16 times the mass of Jupiter) not even deuterium burning can occur, and these objects are perhaps b ...
sections 16-18 instructor notes
... extreme values for globular clusters. This technique also has uncertainties owing to the unknown rate of rotation for the globular cluster system about the Galactic centre, as well as to the possible existence of two distinct groups of globulars. An analysis of this type gives a value of 0 ≥ 230 km ...
... extreme values for globular clusters. This technique also has uncertainties owing to the unknown rate of rotation for the globular cluster system about the Galactic centre, as well as to the possible existence of two distinct groups of globulars. An analysis of this type gives a value of 0 ≥ 230 km ...
Constraints on the Birth Aggregate of the Solar System
... the binary orbit, the asymptotic incoming velocity vinf of the solar system with respect to the center of mass of the binary, the angles θ, ψ, and φ which describe the impact direction and orientation, and finally the impact parameter h of the collision. Additional (intrinsic) parameters are require ...
... the binary orbit, the asymptotic incoming velocity vinf of the solar system with respect to the center of mass of the binary, the angles θ, ψ, and φ which describe the impact direction and orientation, and finally the impact parameter h of the collision. Additional (intrinsic) parameters are require ...
Additional Cosmology Images
... clusters NGC 265 and NGC 290 in the Small Magellanic Cloud — two sparkling sets of gemstones in the southern sky. These images, taken with Hubble's Advanced Camera for Surveys, show a myriad of stars in crystal clear detail. The brilliant open star clusters are located about 200,000 lightyears away ...
... clusters NGC 265 and NGC 290 in the Small Magellanic Cloud — two sparkling sets of gemstones in the southern sky. These images, taken with Hubble's Advanced Camera for Surveys, show a myriad of stars in crystal clear detail. The brilliant open star clusters are located about 200,000 lightyears away ...
Article PDF - IOPscience
... are created in order to provide an initial guess of the background. At the same time, the X, Y offsets between each image and a reference image (for G11 the image u9x6f001m_c0f in the HST archive, see http://archive.stsci.edu/) are measured using the IMEXAMINE task in IRAF. These offsets are input i ...
... are created in order to provide an initial guess of the background. At the same time, the X, Y offsets between each image and a reference image (for G11 the image u9x6f001m_c0f in the HST archive, see http://archive.stsci.edu/) are measured using the IMEXAMINE task in IRAF. These offsets are input i ...
sections 16-18 instructor notes
... extreme values for globular clusters. This technique also has uncertainties owing to the unknown rate of rotation for the globular cluster system about the Galactic centre, as well as to the possible existence of two distinct groups of globulars. An analysis of this type gives a value of 0 ≥ 230 km ...
... extreme values for globular clusters. This technique also has uncertainties owing to the unknown rate of rotation for the globular cluster system about the Galactic centre, as well as to the possible existence of two distinct groups of globulars. An analysis of this type gives a value of 0 ≥ 230 km ...
Open cluster
An open cluster, also known as galactic cluster, is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist. They are loosely bound by mutual gravitational attraction and become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic center, resulting in a migration to the main body of the galaxy as well as a loss of cluster members through internal close encounters. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral and irregular galaxies, in which active star formation is occurring.Young open clusters may still be contained within the molecular cloud from which they formed, illuminating it to create an H II region. Over time, radiation pressure from the cluster will disperse the molecular cloud. Typically, about 10% of the mass of a gas cloud will coalesce into stars before radiation pressure drives the rest of the gas away.Open clusters are key objects in the study of stellar evolution. Because the cluster members are of similar age and chemical composition, their properties (such as distance, age, metallicity and extinction) are more easily determined than they are for isolated stars. A number of open clusters, such as the Pleiades, Hyades or the Alpha Persei Cluster are visible with the naked eye. Some others, such as the Double Cluster, are barely perceptible without instruments, while many more can be seen using binoculars or telescopes. The Wild Duck Cluster, M11, is an example.