Astronomy 140 Lecture Notes, Spring 2008 c
... Magnitudes: the apparent magnitude is m = −2.5 log(F/F◦ ). [Note that log is the common logarithm (base 10) in astronomical usage. Thus a 1% change in flux is a change of 0.0108 in magnitude.] The standard flux for 0th magnitude is tabulated for various photometric bands in different photometric sys ...
... Magnitudes: the apparent magnitude is m = −2.5 log(F/F◦ ). [Note that log is the common logarithm (base 10) in astronomical usage. Thus a 1% change in flux is a change of 0.0108 in magnitude.] The standard flux for 0th magnitude is tabulated for various photometric bands in different photometric sys ...
Program and Abstract Book - European Southern Observatory
... The Hunter's slingshot: Protostellar ejection from filaments in Orion Tjarda Boekholt (Universidad de Concepción, Chile) We compare 3 constituents of Orion A (gas, protostars, and pre-main-sequence stars), both morphologically and kinematically, to show the following. Essentially all protostars lie ...
... The Hunter's slingshot: Protostellar ejection from filaments in Orion Tjarda Boekholt (Universidad de Concepción, Chile) We compare 3 constituents of Orion A (gas, protostars, and pre-main-sequence stars), both morphologically and kinematically, to show the following. Essentially all protostars lie ...
Simulations of the galaxy population constrained by observations
... We propose a specific model in which reincorporation timescales vary inversely with halo mass and are independent of redshift. This produces an evolving galaxy population which fits observed abundances as a function of stellar mass, B- and K-band luminosity at all redshifts simultaneously. It also p ...
... We propose a specific model in which reincorporation timescales vary inversely with halo mass and are independent of redshift. This produces an evolving galaxy population which fits observed abundances as a function of stellar mass, B- and K-band luminosity at all redshifts simultaneously. It also p ...
Open clusters and associations in the Gaia era
... if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As for the second step, this is probably the one that suffers from the largest uncertain ...
... if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As for the second step, this is probably the one that suffers from the largest uncertain ...
Chapter 3 How Earth and Sky Work
... In 12 hours, the sphere moves half way around. Ignoring depth in the diagram, stars, the Sun, the Moon and the planets appear to move horizontally from one side of the figure to the other, keeping the same declination. Over the next 12 hours they move back to their original positions. Bodies at some ...
... In 12 hours, the sphere moves half way around. Ignoring depth in the diagram, stars, the Sun, the Moon and the planets appear to move horizontally from one side of the figure to the other, keeping the same declination. Over the next 12 hours they move back to their original positions. Bodies at some ...
Answers to Chapter Review Questions and Problems for The
... Answer: Stars are other suns. Our sun is a star. A longer definition of a star is that it is a self-luminous sphere of gas (or plasma) deriving its energy from nuclear reactions in its core. 2. What are constellations? How are they defined? Answer: Constellations are recognizable patterns of stars u ...
... Answer: Stars are other suns. Our sun is a star. A longer definition of a star is that it is a self-luminous sphere of gas (or plasma) deriving its energy from nuclear reactions in its core. 2. What are constellations? How are they defined? Answer: Constellations are recognizable patterns of stars u ...
Sky and Telescope - CAMS
... out to be the most interesting for meteor observations. The new CAMS data show that at least 14 significant showers are active that week, each with its own particular radiant direction on the sky, velocity, duration (indicating stream width), and behavior. Five of these showers were completely new t ...
... out to be the most interesting for meteor observations. The new CAMS data show that at least 14 significant showers are active that week, each with its own particular radiant direction on the sky, velocity, duration (indicating stream width), and behavior. Five of these showers were completely new t ...
Confirmation of Hostless Type Ia Supernovae Using Hubble Space
... Supernovae of Type Ia (SNe Ia) are the thermonuclear explosions of carbon-oxygen white dwarf (CO WD) stars, commonly used as cosmological standard candles although their progenitor scenario is not yet well understood (e.g., Howell 2011). Most likely, the WD is in a binary system with either another ...
... Supernovae of Type Ia (SNe Ia) are the thermonuclear explosions of carbon-oxygen white dwarf (CO WD) stars, commonly used as cosmological standard candles although their progenitor scenario is not yet well understood (e.g., Howell 2011). Most likely, the WD is in a binary system with either another ...
Notes on Stars
... Once one knows the distances and hence the absolute magnitudes, one can plot the fundamental diagram of stellar astrophysics: the color-magnitude diagram or Hertzsprung-Russel diagram. Already around 1910, Rosenberg, Hertzsprung and Russel discuss what is now called the Hertsprung-Russel Diagram. Th ...
... Once one knows the distances and hence the absolute magnitudes, one can plot the fundamental diagram of stellar astrophysics: the color-magnitude diagram or Hertzsprung-Russel diagram. Already around 1910, Rosenberg, Hertzsprung and Russel discuss what is now called the Hertsprung-Russel Diagram. Th ...
Antares Palette - RASC Kingston Centre
... shows what appears to be a normal-looking globular cluster. However, M54 is not a part of the Milky Way’s collection of 150 globulars, but instead belongs to the Sagittarius Dwarf Galaxy, which lies at a distance of about 90,000 light-years and is the closest external galaxy to our own. M54 apparent ...
... shows what appears to be a normal-looking globular cluster. However, M54 is not a part of the Milky Way’s collection of 150 globulars, but instead belongs to the Sagittarius Dwarf Galaxy, which lies at a distance of about 90,000 light-years and is the closest external galaxy to our own. M54 apparent ...
Ages of young stars
... individual objects. A reliable age scale is established above 20 Myr from measurement of the Lithium Depletion Boundary (LDB) in young clusters, and consistency is shown between these ages and those from the upper main sequence and the main sequence turn-off – if modest core convection and rotation ...
... individual objects. A reliable age scale is established above 20 Myr from measurement of the Lithium Depletion Boundary (LDB) in young clusters, and consistency is shown between these ages and those from the upper main sequence and the main sequence turn-off – if modest core convection and rotation ...
Ages of Young Stars
... (l) Cargile and James (2010), (m) Naylor et al. (2009), (n) derived by E. Mamajek using data from Hauck and Mermilliod (1998) and isochrones from Bertelli et al. (2009), (o) Ventura et al. (1998). ally negligible) and, presented separately, the systematic absolute age uncertainty estimated by Burke ...
... (l) Cargile and James (2010), (m) Naylor et al. (2009), (n) derived by E. Mamajek using data from Hauck and Mermilliod (1998) and isochrones from Bertelli et al. (2009), (o) Ventura et al. (1998). ally negligible) and, presented separately, the systematic absolute age uncertainty estimated by Burke ...
Classification of Variable Stars
... on to ZZ. Then, the naming starts over at the beginning of the alphabet: AA, AB, and continuing on to QZ. This system (the letter J is omitted) can accommodate 334 names. There are so many variables in some constellations in the Milky Way, however, that additional nomenclature is necessary. After QZ ...
... on to ZZ. Then, the naming starts over at the beginning of the alphabet: AA, AB, and continuing on to QZ. This system (the letter J is omitted) can accommodate 334 names. There are so many variables in some constellations in the Milky Way, however, that additional nomenclature is necessary. After QZ ...
The Evolution of Molecular Clouds
... than the Galactic average, yields a formation timescale for molecular clouds of about 50 Myr (Larson 1991a, 1992b). Note that this estimated formation time is not much longer than the cloud lifetime of ∼ 20 Myr (Section 2); thus the formation of molecular clouds must itself be a rather rapid process ...
... than the Galactic average, yields a formation timescale for molecular clouds of about 50 Myr (Larson 1991a, 1992b). Note that this estimated formation time is not much longer than the cloud lifetime of ∼ 20 Myr (Section 2); thus the formation of molecular clouds must itself be a rather rapid process ...
How We See The Sky
... Diffraction places a limit on the resolution of an optical system. As detail becomes smaller, diffraction has a proportionally stronger “smearing” effect (failure to fully “transfer” scene contrast), diminishing the ability of the optical system to resolve fine detail. High MTF at low contrast level ...
... Diffraction places a limit on the resolution of an optical system. As detail becomes smaller, diffraction has a proportionally stronger “smearing” effect (failure to fully “transfer” scene contrast), diminishing the ability of the optical system to resolve fine detail. High MTF at low contrast level ...
Variations in Integrated Galactic Initial Mass Functions due to
... sion in early type galaxies and the rates of supernovae of both Type II and Ia in several galaxy types in the light of the IGIMF framework. They find that if one assumes a constant star formation rate over a Hubble time, then for all but the irregular galaxies these numbers agree well with the obser ...
... sion in early type galaxies and the rates of supernovae of both Type II and Ia in several galaxy types in the light of the IGIMF framework. They find that if one assumes a constant star formation rate over a Hubble time, then for all but the irregular galaxies these numbers agree well with the obser ...
Astronomy Astrophysics - Niels Bohr Institutet
... Extensive uvbyβ photometric surveys of the nearby F and G stars have been performed by Olsen (1983, 1993, 1994a, 1994b). Accurate parallaxes and proper motions have become available for large numbers of these stars from the Hipparcos (ESA 1997) and Tycho-2 (Høg et al. 2000) catalogues. The bottlenec ...
... Extensive uvbyβ photometric surveys of the nearby F and G stars have been performed by Olsen (1983, 1993, 1994a, 1994b). Accurate parallaxes and proper motions have become available for large numbers of these stars from the Hipparcos (ESA 1997) and Tycho-2 (Høg et al. 2000) catalogues. The bottlenec ...
Ursa Major
Ursa Major /ˈɜrsə ˈmeɪdʒər/ (also known as the Great Bear and Charles' Wain) is a constellation in the northern celestial hemisphere. One of the 48 constellations listed by Ptolemy (second century AD), it remains one of the 88 modern constellations. It can be visible throughout the year in most of the northern hemisphere. Its name, Latin for ""the greater (or larger) she-bear"", stands as a reference to and in direct contrast with Ursa Minor, ""the smaller she-bear"", with which it is frequently associated in mythology and amateur astronomy. The constellation's most recognizable asterism, a group of seven relatively bright stars commonly known as the ""Big Dipper"", ""the Wagon"" or ""the Plough"" (among others), both mimicks the shape of the lesser bear (the ""Little Dipper"") and is commonly used as a navigational pointer towards the current northern pole star, Polaris in Ursa Minor. The Big Dipper and the constellation as a whole have mythological significance in numerous world cultures, usually as a symbol of the north.The third largest constellation in the sky, Ursa Major is home to many deep-sky objects including seven Messier objects, four other NGC objects and I Zwicky 18, the youngest known galaxy in the visible universe.