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Meade Introduction: 7" Mak, 8", 10" and 12"
... in the telescopic field to a precision of one arc-minute. Meade LX200GPS models perform such feats of pointing precision time after time, on object after object, enabling the user to observe or photograph extremely faint galaxies, for example, at the very limit of the telescope’s capability, knowing ...
... in the telescopic field to a precision of one arc-minute. Meade LX200GPS models perform such feats of pointing precision time after time, on object after object, enabling the user to observe or photograph extremely faint galaxies, for example, at the very limit of the telescope’s capability, knowing ...
Five Planets and an Independent Confirmation of
... typical seeing at Lick of 1.′′ 5, the exposure time for SNR of 140 is about 5 minutes on the 3-m Shane telescope or about 30 minutes on the 0.6-m Coudé Auxiliary Telescope (CAT). The observation dates, radial velocities and measurement uncertainties are listed in Table 2. The initial phase coverage ...
... typical seeing at Lick of 1.′′ 5, the exposure time for SNR of 140 is about 5 minutes on the 3-m Shane telescope or about 30 minutes on the 0.6-m Coudé Auxiliary Telescope (CAT). The observation dates, radial velocities and measurement uncertainties are listed in Table 2. The initial phase coverage ...
Optical and Infrared Colors of Stars Observed by the
... [0.1 \ g*[r* \ 0.3, r*[i* \ 0.5) and are brighter than the limit for quasars in the SDSS spectroscopic survey (i* \ 19) are marked by open circles. The locus of ““ normal ÏÏ stars stands out in all three diagrams. As shown by Fukugita et al. (1996), Krisciunas, Margon, & Szkody (1998), Lenz et al. ( ...
... [0.1 \ g*[r* \ 0.3, r*[i* \ 0.5) and are brighter than the limit for quasars in the SDSS spectroscopic survey (i* \ 19) are marked by open circles. The locus of ““ normal ÏÏ stars stands out in all three diagrams. As shown by Fukugita et al. (1996), Krisciunas, Margon, & Szkody (1998), Lenz et al. ( ...
Rapid Rotation of Low-Mass Red Giants Using APOKASC: A
... & Reiners 2011), and declare all giants rotating faster than this rate to be ’rapid rotators’. While this is a conservative approach to selecting interaction products, a single value does not allow identification of all stars in a sample that have been spun up by unusual evolution, because low-mass ...
... & Reiners 2011), and declare all giants rotating faster than this rate to be ’rapid rotators’. While this is a conservative approach to selecting interaction products, a single value does not allow identification of all stars in a sample that have been spun up by unusual evolution, because low-mass ...
properties and evolution of disks around pre-main
... Amsterdam in 1993 (The´ et al. 1994b), and recent work has been cov´ ered in a number of reviews such as those by Perez and Grady (1997) and by Waters and Waelkens (1998). We refer the reader to these reviews for complete summaries of the observational properties of HAeBe stars. In this work, we con ...
... Amsterdam in 1993 (The´ et al. 1994b), and recent work has been cov´ ered in a number of reviews such as those by Perez and Grady (1997) and by Waters and Waelkens (1998). We refer the reader to these reviews for complete summaries of the observational properties of HAeBe stars. In this work, we con ...
LATE STAGES OF CLOSE BINARY SYSTEMS 1. Introduction The X
... difficulty, finish as a white dwarf. A1.4Af© helium core corresponds to an initial primary mass Mi of about 8Af . For systems with A ^ <,3M® the evolution to the white dwarf stage has been verified by computations (Kippenhahn et al., 1967; further references in Paczynski, 1971a); here the mass of th ...
... difficulty, finish as a white dwarf. A1.4Af© helium core corresponds to an initial primary mass Mi of about 8Af . For systems with A ^ <,3M® the evolution to the white dwarf stage has been verified by computations (Kippenhahn et al., 1967; further references in Paczynski, 1971a); here the mass of th ...
Massive z~1.3 evolved galaxies revealed
... In order to obtain a lower limit to the luminosity of the two galaxies and a model independent estimate of their stellar mass, we conservatively placed both of them at z = 1.2. Using a k-correction ∆K = −0.6 mag (Mannucci et al. 2001) we estimate a lower limit to their rest-frame K-band absolute mag ...
... In order to obtain a lower limit to the luminosity of the two galaxies and a model independent estimate of their stellar mass, we conservatively placed both of them at z = 1.2. Using a k-correction ∆K = −0.6 mag (Mannucci et al. 2001) we estimate a lower limit to their rest-frame K-band absolute mag ...
BD−21 3873: another yellow-symbiotic barium star
... in AG Dra, which is not surprising in view of the larger temperature of the ionizing source in AG Dra (170 000 K) compared to BD−21◦ 3873 (75 000 K; Schmid & Nussbaumer 1993). Alternatively, orbital modulation may be responsible for the fact that the spectral features triggered by the ionizing sourc ...
... in AG Dra, which is not surprising in view of the larger temperature of the ionizing source in AG Dra (170 000 K) compared to BD−21◦ 3873 (75 000 K; Schmid & Nussbaumer 1993). Alternatively, orbital modulation may be responsible for the fact that the spectral features triggered by the ionizing sourc ...
An atlas of 2.4 to 4.1 mu m ISO/SWS spectra of early - UvA-DARE
... later type stars the situation is reversed, i.e. only 5 out of 23 have S/N ≤ 60. This tendency is explained by the lack of relatively nearby bright O and early-B stars compared to later B stars. For the B stars with emission lines, the S/N of the continuum is not that important as the emission lines ...
... later type stars the situation is reversed, i.e. only 5 out of 23 have S/N ≤ 60. This tendency is explained by the lack of relatively nearby bright O and early-B stars compared to later B stars. For the B stars with emission lines, the S/N of the continuum is not that important as the emission lines ...
Galactic astroarchaeology: reconstructing the bulge history by
... milder and continuous star formation rate (SFR). These assumptions, coupled with the time-delay between the Fe enrichment from type Ia supernovae (white dwarfs in binary systems) and the α-element enrichment from core collapse supernovae (originating in massive stars, type II, Ib/c) produce a differe ...
... milder and continuous star formation rate (SFR). These assumptions, coupled with the time-delay between the Fe enrichment from type Ia supernovae (white dwarfs in binary systems) and the α-element enrichment from core collapse supernovae (originating in massive stars, type II, Ib/c) produce a differe ...
Stellar multiplicity and debris discs: an unbiased sample
... for the DEBRIS sample in order to search for and characterize farIR emission from circumstellar (or circumbinary) dust. Except for cases in which a companion fell within the field of view, we did not explicitly aim to observe companions with exception of Fomalhaut’s companions, of which companionshi ...
... for the DEBRIS sample in order to search for and characterize farIR emission from circumstellar (or circumbinary) dust. Except for cases in which a companion fell within the field of view, we did not explicitly aim to observe companions with exception of Fomalhaut’s companions, of which companionshi ...
Chandra News The Secret X-ray Lives of Planetary Nebulae
... emission from hot central star photospheres (Fig. 5). of their evolution, perhaps even before the progenitor Instead, such emission evidently originates, at least in AGB stars blow away their last, innermost, chemically rich layers of stellar envelope (e.g., Sahai & Trauger 1998). ...
... emission from hot central star photospheres (Fig. 5). of their evolution, perhaps even before the progenitor Instead, such emission evidently originates, at least in AGB stars blow away their last, innermost, chemically rich layers of stellar envelope (e.g., Sahai & Trauger 1998). ...
Str\" omgren uvby photometry of the peculiar globular cluster NGC
... these indices approximately compensates the shift due to CN. Compared to a single continuous distribution with finite dispersion, the observed δ4 distribution of red giants is slightly better fit by two distinct populations with no internal spread, with the nitrogenenhanced second generation account ...
... these indices approximately compensates the shift due to CN. Compared to a single continuous distribution with finite dispersion, the observed δ4 distribution of red giants is slightly better fit by two distinct populations with no internal spread, with the nitrogenenhanced second generation account ...
thesis
... Star formation occurs in cold dense clouds of gas and dust. While the cloud is supported by magnetic fields and turbulence, the densest regions can collapse under the influence of gravity. At the centre of these dense cores, a star begins to form. During this process it is thought that a circumstell ...
... Star formation occurs in cold dense clouds of gas and dust. While the cloud is supported by magnetic fields and turbulence, the densest regions can collapse under the influence of gravity. At the centre of these dense cores, a star begins to form. During this process it is thought that a circumstell ...
They might be giants: luminosity class, planet frequency, and planet
... 2011, henceforth SL11), and the characteristics of multiplanet systems (Fabrycky et al. 2012). These findings yield important constraints on models of planet formation and evolution, and are best established for solar-type stars (late F through early K spectral types) because they constitute the vas ...
... 2011, henceforth SL11), and the characteristics of multiplanet systems (Fabrycky et al. 2012). These findings yield important constraints on models of planet formation and evolution, and are best established for solar-type stars (late F through early K spectral types) because they constitute the vas ...
Confronting Dark Matter Powered Stars with Recent Results from
... Matter powered star (Dark Star). The properties of such a Dark Star (DS) may be altered in comparison to a normal Pop III star. Dark Stars are predicted to be cooler, larger, more massive and potentially longer lived, due to their additional energy source. Using the PHOENIX atmospheric code, stellar ...
... Matter powered star (Dark Star). The properties of such a Dark Star (DS) may be altered in comparison to a normal Pop III star. Dark Stars are predicted to be cooler, larger, more massive and potentially longer lived, due to their additional energy source. Using the PHOENIX atmospheric code, stellar ...
they might be giants: luminosity class, planet occurrence, and planet
... important conclusions about late-type exoplanet hosts. First, H11 found that the frequency of stars with planets on close-in (P< 50d) orbits rises with decreasing effective temperature through early K-type and that an even higher fraction of M dwarf stars may host such planets. Second, SL11 claimed ...
... important conclusions about late-type exoplanet hosts. First, H11 found that the frequency of stars with planets on close-in (P< 50d) orbits rises with decreasing effective temperature through early K-type and that an even higher fraction of M dwarf stars may host such planets. Second, SL11 claimed ...
Yellow supergiants as supernova progenitors: an indication of
... a plateau in the lightcurves of the types IIL and IIb SNe indicates that the hydrogen envelope ejected during the explosion must be small. We adopt here the same criterion as in Heger et al. (2003) and Eldridge & Tout (2004) to distinguish between type IIP and IIL SNe: it is a type IIL if the ejecte ...
... a plateau in the lightcurves of the types IIL and IIb SNe indicates that the hydrogen envelope ejected during the explosion must be small. We adopt here the same criterion as in Heger et al. (2003) and Eldridge & Tout (2004) to distinguish between type IIP and IIL SNe: it is a type IIL if the ejecte ...
Cluster formation in molecular clouds – I. Stellar populations, star
... feedback from stars with pre-stellar evolution and those without it. The authors found that there was not a significant difference between the two cases. Since the cluster will be actively accreting gas until feedback effects stop the inflow, any added mass has to be dealt with accordingly. This gas ...
... feedback from stars with pre-stellar evolution and those without it. The authors found that there was not a significant difference between the two cases. Since the cluster will be actively accreting gas until feedback effects stop the inflow, any added mass has to be dealt with accordingly. This gas ...
Runaway collisions in young star clusters – II. Numerical results
... in less than the MS lifetime of massive stars (3 Myr), we obtain the growth of a single very massive star (VMS, M∗ 400–4000 M ) through a runaway sequence of mergers. Mass loss from collisions, even for velocity dispersions as high as σ v ∼ 1000 km s−1 , does not prevent the runaway. The region ...
... in less than the MS lifetime of massive stars (3 Myr), we obtain the growth of a single very massive star (VMS, M∗ 400–4000 M ) through a runaway sequence of mergers. Mass loss from collisions, even for velocity dispersions as high as σ v ∼ 1000 km s−1 , does not prevent the runaway. The region ...
M sun
... Many ULX radio lobes may have been misclassified as SNRs if the central X-ray source is off Ratio of ULX radio lobes / “fossil” radio lobes may give us clues on the X-ray duty cycle Radio/ULX associations useful to determine ...
... Many ULX radio lobes may have been misclassified as SNRs if the central X-ray source is off Ratio of ULX radio lobes / “fossil” radio lobes may give us clues on the X-ray duty cycle Radio/ULX associations useful to determine ...
Best of British telescopes How to plan your own
... planets. Dwarf galaxies are typically representative of conditions in the early Universe, when heavy elements did not exist in large quantities. Could the Universe have started forming planets sooner than we realised? “For example,” says Rainer Klement, who was part of the team that found the planet ...
... planets. Dwarf galaxies are typically representative of conditions in the early Universe, when heavy elements did not exist in large quantities. Could the Universe have started forming planets sooner than we realised? “For example,” says Rainer Klement, who was part of the team that found the planet ...
Roche accretion of stars close to massive black holes
... is the quasi-periodic XMM–Newton X-ray signal from a nearby active type 1 Seyfert galaxy RE J1034+396 observed by Gierliński et al. (2008). As shown in fig. 1 in their paper, the rest-frame X-ray emission has a period of ∼ 1 h. The X-ray flux has a modulation of ∼0.1 associated with the nucleus of ...
... is the quasi-periodic XMM–Newton X-ray signal from a nearby active type 1 Seyfert galaxy RE J1034+396 observed by Gierliński et al. (2008). As shown in fig. 1 in their paper, the rest-frame X-ray emission has a period of ∼ 1 h. The X-ray flux has a modulation of ∼0.1 associated with the nucleus of ...
Lecture 21 (pdf from the powerpoint)
... •Diameter of the known universe ~ 8 x 10^10 LY •Avg distance between galaxies ~ 1 million LY (10 to 30 big galaxy diameters) •If lake Mendota was the observable universe then each galaxy would be about 25 mm across and separated by about 1/2 meter away. •In contrast if the galaxy was the size of Men ...
... •Diameter of the known universe ~ 8 x 10^10 LY •Avg distance between galaxies ~ 1 million LY (10 to 30 big galaxy diameters) •If lake Mendota was the observable universe then each galaxy would be about 25 mm across and separated by about 1/2 meter away. •In contrast if the galaxy was the size of Men ...
Metallicities of Planet Hosting Stars: A Sample of Giants and Subgiants
... would be supported by the lower metallicities of giants with planets, which having been enhanced on the MS, would be diluted by the deepening convection zones as the stars evolve up the red giant branch. An observational result that has been used as an argument in favor of the primordial enrichment ...
... would be supported by the lower metallicities of giants with planets, which having been enhanced on the MS, would be diluted by the deepening convection zones as the stars evolve up the red giant branch. An observational result that has been used as an argument in favor of the primordial enrichment ...
Planetary nebula
![](https://commons.wikimedia.org/wiki/Special:FilePath/NGC6543.jpg?width=300)
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.