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SearchCal: a Virtual Observatory tool for searching - HAL-Insu
... with the Palomar Testbed Interferometer (PTI) and Keck Interferometer (KI), an interferometric observation planning software GetCal has been developed (Boden 2003), including a tool to compute the visibility of potential reference stars taken in the Hipparcos catalog and extracting astronomical and ...
... with the Palomar Testbed Interferometer (PTI) and Keck Interferometer (KI), an interferometric observation planning software GetCal has been developed (Boden 2003), including a tool to compute the visibility of potential reference stars taken in the Hipparcos catalog and extracting astronomical and ...
Beta Pictoris and Other Solar Systems
... initially to β Pic (cf. Artymowicz, 1997). However, the effects of radiation are quite similar in different systems (e. g., Artymowicz and Clampin, 1997). For instance, the luminosity differences between the stars will simply shift the ‘blow-out grain radius’ but will not change the characteristic s ...
... initially to β Pic (cf. Artymowicz, 1997). However, the effects of radiation are quite similar in different systems (e. g., Artymowicz and Clampin, 1997). For instance, the luminosity differences between the stars will simply shift the ‘blow-out grain radius’ but will not change the characteristic s ...
Chemical evolution models for the dwarf spheroidal galaxies Leo 1
... The initial total mass is the main driver of the system in their simulation, contrary to LM03 and LM04 in which the SF and wind efficiencies play the major role. Since the final gas mass predicted in their simulations is much higher than the values inferred by observations, they claim the necessity of ...
... The initial total mass is the main driver of the system in their simulation, contrary to LM03 and LM04 in which the SF and wind efficiencies play the major role. Since the final gas mass predicted in their simulations is much higher than the values inferred by observations, they claim the necessity of ...
stellar diameters and temperatures. iii. main-sequence a, f, g
... we used the SearchCal tool developed by the JMMC Working Group (Bonneau et al. 2006, 2011). These calibrator stars are listed in Table 1 , and the value of the estimated angular diameters θEST is taken from the SearchCal catalog value for the estimated limb-darkened angular diameter. In order to ens ...
... we used the SearchCal tool developed by the JMMC Working Group (Bonneau et al. 2006, 2011). These calibrator stars are listed in Table 1 , and the value of the estimated angular diameters θEST is taken from the SearchCal catalog value for the estimated limb-darkened angular diameter. In order to ens ...
Stellar Population Effects on the Inferred Photon Density at
... reliably estimated. However difficulties arise when any of these properties are unknown. A young starburst will contain a larger proportion of hot, massive stars than an older one and so emit more ionizing photons for a given 1500Å continuum measurement. By contrast, a stellar population that has for ...
... reliably estimated. However difficulties arise when any of these properties are unknown. A young starburst will contain a larger proportion of hot, massive stars than an older one and so emit more ionizing photons for a given 1500Å continuum measurement. By contrast, a stellar population that has for ...
1. INTRODUCTION 2. MASS AND LIGHT
... D3¡ to account for the observed events). This possibility could only apply to a self-gravitating structure and not to an intrinsically extended one such as tidal debris. 3. The argument of ° 2 fails because the intervening material is smooth on scales of D15¡ in both directions, the size of de Vauco ...
... D3¡ to account for the observed events). This possibility could only apply to a self-gravitating structure and not to an intrinsically extended one such as tidal debris. 3. The argument of ° 2 fails because the intervening material is smooth on scales of D15¡ in both directions, the size of de Vauco ...
The close circumstellar environment of Betelgeuse
... compact. Conclusions. The circumstellar envelope around Betelgeuse extends at least up to several tens of stellar radii. Its relatively high degree of clumpiness indicates an inhomogeneous spatial distribution of the material lost by the star. Its extension corresponds to an important intermediate s ...
... compact. Conclusions. The circumstellar envelope around Betelgeuse extends at least up to several tens of stellar radii. Its relatively high degree of clumpiness indicates an inhomogeneous spatial distribution of the material lost by the star. Its extension corresponds to an important intermediate s ...
Conditions for water ice lines and Mars-mass
... we will test values over two orders of magnitude to explore the effects of changing opacities. The vertical gas density in the disk is approximated with an isothermal profile, which is appropriate because we are mostly interested in the very final stages of accretion when the disk midplane and the d ...
... we will test values over two orders of magnitude to explore the effects of changing opacities. The vertical gas density in the disk is approximated with an isothermal profile, which is appropriate because we are mostly interested in the very final stages of accretion when the disk midplane and the d ...
OGLE 2008–BLG–290: an accurate measurement of the limb
... A few days later, it was clear that this event had the potential to become one of the rare high-magnification events discovered each year, and follow-up observations were undertaken on PLANET, μFUN, RoboNet/LCOGT and MiNDSTEp telescopes available at that time. In total, 13 telescopes covered the eve ...
... A few days later, it was clear that this event had the potential to become one of the rare high-magnification events discovered each year, and follow-up observations were undertaken on PLANET, μFUN, RoboNet/LCOGT and MiNDSTEp telescopes available at that time. In total, 13 telescopes covered the eve ...
outer-disk populations in ngc 7793: evidence for stellar
... little evidence of migration in HST observations of NGC 300, and less migration in the NGC 300 simulation than the Roškar et al. (2008b) model. This led the authors to suggest that both mass and environment may be factors in radial migration. As the formation of transient spiral structure is linked ...
... little evidence of migration in HST observations of NGC 300, and less migration in the NGC 300 simulation than the Roškar et al. (2008b) model. This led the authors to suggest that both mass and environment may be factors in radial migration. As the formation of transient spiral structure is linked ...
A Massive Galaxy in its Core Formation Phase Three Billion Years
... (log(M/M⊙ )(r < 1 kpc) ≥ 10.5; see ref. 7), and a concentrated stellar distribution (re ≤ 1 kpc). We observed all three galaxies with Keck and GOODS-N-774 is the only confirmed candidate: GOODS-S-59816 has a narrow line width, whereas COSMOS-8388 is difficult to interpret because it has an active nu ...
... (log(M/M⊙ )(r < 1 kpc) ≥ 10.5; see ref. 7), and a concentrated stellar distribution (re ≤ 1 kpc). We observed all three galaxies with Keck and GOODS-N-774 is the only confirmed candidate: GOODS-S-59816 has a narrow line width, whereas COSMOS-8388 is difficult to interpret because it has an active nu ...
The chemical composition of IK Pegasi
... spectral type is intermediate between the two. This defines the classical Am stars. A marginal Am star is one in which the metallic and calcium types differ by less than five subtypes. These definitions only describe the appearance of the spectrum and do not imply anything about the abundances of th ...
... spectral type is intermediate between the two. This defines the classical Am stars. A marginal Am star is one in which the metallic and calcium types differ by less than five subtypes. These definitions only describe the appearance of the spectrum and do not imply anything about the abundances of th ...
A Test of Pre-Main-Sequence Lithium Depletion Models
... clusters, focusing on comparing the cluster age derived from the lithium depletion boundary (LDB)1 in the lowest-mass stars with the HR diagram age found from fitting the upper main sequence (e.g. Barrado y Navascués, Stauffer, & Patten 1999; Stauffer et al. 1999; Burke et al. 2004; Jeffries & Oliv ...
... clusters, focusing on comparing the cluster age derived from the lithium depletion boundary (LDB)1 in the lowest-mass stars with the HR diagram age found from fitting the upper main sequence (e.g. Barrado y Navascués, Stauffer, & Patten 1999; Stauffer et al. 1999; Burke et al. 2004; Jeffries & Oliv ...
Clouds in the atmospheres of extrasolar planets
... climate model, which accounts directly for the climatic and radiative effects of multi-layered clouds (see Kitzmann et al. 2010, henceforth called Paper I, for a detailed model description). In particular the influence of two different cloud layers (low-level water and high-level ice clouds) is includ ...
... climate model, which accounts directly for the climatic and radiative effects of multi-layered clouds (see Kitzmann et al. 2010, henceforth called Paper I, for a detailed model description). In particular the influence of two different cloud layers (low-level water and high-level ice clouds) is includ ...
Galaxy Classification Much of modern extragalactic astronomy deals
... ultraviolet. (In other words, since elliptical galaxies are made up of old stars, the composite spectrum of an elliptical should look like that of a ∼ 4, 000◦ K star. However, many ellipticals are brighter at 1500 Å than they are at 2000 Å.) 5) There is very little cold interstellar medium in elli ...
... ultraviolet. (In other words, since elliptical galaxies are made up of old stars, the composite spectrum of an elliptical should look like that of a ∼ 4, 000◦ K star. However, many ellipticals are brighter at 1500 Å than they are at 2000 Å.) 5) There is very little cold interstellar medium in elli ...
The density of very massive evolved galaxies to z≃ 1.7
... would have at z = 0. This has been obtained by assuming a pure passive evolution from z spec to z = 0. The luminosities thus obtained are reported in Table 1 and place the lower limit at 1.9L∗ as imposed by S2F1 633. In the second way, we derived the K-band luminosity from the lowest stellar mass of ...
... would have at z = 0. This has been obtained by assuming a pure passive evolution from z spec to z = 0. The luminosities thus obtained are reported in Table 1 and place the lower limit at 1.9L∗ as imposed by S2F1 633. In the second way, we derived the K-band luminosity from the lowest stellar mass of ...
Historical introduction
... Lecture 1 Harlow Shapley and the distance to the centre of the Galaxy, 1918 ...
... Lecture 1 Harlow Shapley and the distance to the centre of the Galaxy, 1918 ...
A PCA approach to stellar effective temperatures⋆
... high-quality spectroscopic temperatures in the Elodie library, we define a temperature scale for FG-type disk dwarfs with an internal consistency of about 50 K, in excellent agreement with temperatures from direct determinations and widely used scales based on the infrared flux method. Key words. st ...
... high-quality spectroscopic temperatures in the Elodie library, we define a temperature scale for FG-type disk dwarfs with an internal consistency of about 50 K, in excellent agreement with temperatures from direct determinations and widely used scales based on the infrared flux method. Key words. st ...
Stellar Metamorphosis
... ever. [15][16] These stars simply formed in different areas of the galaxy and took up orbit around each other further along their life spans. 8. Gas contraction from gravity alone in the hard vacuum of outer space has never been observed in nature or shown in an experiment. No star has ever been obs ...
... ever. [15][16] These stars simply formed in different areas of the galaxy and took up orbit around each other further along their life spans. 8. Gas contraction from gravity alone in the hard vacuum of outer space has never been observed in nature or shown in an experiment. No star has ever been obs ...
Follow-Up Observations of PTFO 8-8695: A 3 MYr Old T
... the star showed regular transit events with a period of just 0.45 days. But unlike TW Hya, which is a classical T Tauri star with active accretion (Rucinski & Krautter 1983) and has periodic ∼ 2% dips likely caused by the disk occulting a hot spot (Siwak et al. 2014), PTFO 88695, being a WTTS, has n ...
... the star showed regular transit events with a period of just 0.45 days. But unlike TW Hya, which is a classical T Tauri star with active accretion (Rucinski & Krautter 1983) and has periodic ∼ 2% dips likely caused by the disk occulting a hot spot (Siwak et al. 2014), PTFO 88695, being a WTTS, has n ...
IRC −10414: a bow-shock-producing red supergiant star
... Parker et al. 2005), we searched for possible optical counterparts to bow shocks detected in the archival data of the Mid-Infrared Galactic Plane Survey (performed by the Midcourse Space Experiment satellite; Price et al. 2001) and found an arc-like structure (see the left-hand panel of Fig. 1) at ≈ ...
... Parker et al. 2005), we searched for possible optical counterparts to bow shocks detected in the archival data of the Mid-Infrared Galactic Plane Survey (performed by the Midcourse Space Experiment satellite; Price et al. 2001) and found an arc-like structure (see the left-hand panel of Fig. 1) at ≈ ...
Astronomy Astrophysics - Utrecht University Repository
... in density leads to a change in the emerging bound-free and freefree flux emission as long as the emission is optically thin. This approach predicts a single valued relation between colour and magnitude for the B-type star and its varying CSE. The opposite trend, i.e. redder optical colour with decr ...
... in density leads to a change in the emerging bound-free and freefree flux emission as long as the emission is optically thin. This approach predicts a single valued relation between colour and magnitude for the B-type star and its varying CSE. The opposite trend, i.e. redder optical colour with decr ...
Absolute Magnitudes of Turnoff Stars in Globular Clusters Palomar
... representative HR diagrams of globular clusters in SDSS data [3]. A globular cluster is a gravitationally bound group of hundreds of thousands of stars originally formed from one cloud of gas and dust. However, using high accuracy Hubble Space Telescope data, Piotto et al. (2012) recently showed tha ...
... representative HR diagrams of globular clusters in SDSS data [3]. A globular cluster is a gravitationally bound group of hundreds of thousands of stars originally formed from one cloud of gas and dust. However, using high accuracy Hubble Space Telescope data, Piotto et al. (2012) recently showed tha ...
Radiatively driven Rayleigh-Taylor instability candidates around a
... these features represent details of previously known morphology (Fujiyoshi et al. 2001). The 8−12 μm spectro-polarimetric studies have been used to show that the emission in this region is composed of both absorptive and emissive polarized components (Fujiyoshi et al. 2001). Also, significant line e ...
... these features represent details of previously known morphology (Fujiyoshi et al. 2001). The 8−12 μm spectro-polarimetric studies have been used to show that the emission in this region is composed of both absorptive and emissive polarized components (Fujiyoshi et al. 2001). Also, significant line e ...
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.