![Working with Magnitudes and Color Indices 1 A quick review of](http://s1.studyres.com/store/data/007065501_1-d5de6dbe04ce87c12451d1fc346d74fd-300x300.png)
Working with Magnitudes and Color Indices 1 A quick review of
... As the individual stars evolve (age) in the galaxy, the color index of that galaxy will also evolve. The primary reason for this is that the rate of evolution depends on the mass of the star, as does the color index. Thus the high mass stars, which tend to pull the B −V index negative because of the ...
... As the individual stars evolve (age) in the galaxy, the color index of that galaxy will also evolve. The primary reason for this is that the rate of evolution depends on the mass of the star, as does the color index. Thus the high mass stars, which tend to pull the B −V index negative because of the ...
Nuclear Astrophysics
... For temperatures T < 100 MK, the beta decay lifetimes of 13N and 15O are much shorter compared to the lifetimes of 12C and 14N to destruction by protons. In other words, as soon as a 12C + p (or 14N + p) reaction creates 13N (15O) , the newly produced 13N (15O) basically decay before the next new 1 ...
... For temperatures T < 100 MK, the beta decay lifetimes of 13N and 15O are much shorter compared to the lifetimes of 12C and 14N to destruction by protons. In other words, as soon as a 12C + p (or 14N + p) reaction creates 13N (15O) , the newly produced 13N (15O) basically decay before the next new 1 ...
Transiting exoplanets from the CoRoT space mission
... We present the discovery of a candidate multiply transiting system, the first one found in the CoRoT mission. Two transit-like features with periods of 5.11 and 11.76 d are detected in the CoRoT light curve around a main sequence K1V star of r = 15.1. If the features are due to transiting planets ar ...
... We present the discovery of a candidate multiply transiting system, the first one found in the CoRoT mission. Two transit-like features with periods of 5.11 and 11.76 d are detected in the CoRoT light curve around a main sequence K1V star of r = 15.1. If the features are due to transiting planets ar ...
Potassium abundances in nearby metal-poor stars
... Aims. The potassium abundances for 58 metal-poor stars are determined using high-resolution spectroscopy. The abundance trends in stars of different population are discussed. Methods. All abundance results have been derived from NLTE statistical equilibrium calculations and spectrum synthesis methods ...
... Aims. The potassium abundances for 58 metal-poor stars are determined using high-resolution spectroscopy. The abundance trends in stars of different population are discussed. Methods. All abundance results have been derived from NLTE statistical equilibrium calculations and spectrum synthesis methods ...
Elemental ratios in stars vs planets
... further than 0.3 AU, the ratios attain solar values. 4.2. C/O ratio in solids Figures 4 shows the mode value of C/O in solids (refractory species and ices) for the three populations versus the stellar ratio. The C/O ratio in icy and giant planets appears to be very weakly dependent on the C/O ratio ...
... further than 0.3 AU, the ratios attain solar values. 4.2. C/O ratio in solids Figures 4 shows the mode value of C/O in solids (refractory species and ices) for the three populations versus the stellar ratio. The C/O ratio in icy and giant planets appears to be very weakly dependent on the C/O ratio ...
The age structure of the Milky Way`s halo
... number-density contrast. Known over-densities and streams are identified by labels on the maps shown in Fig. 1; locations of these are listed in Table 1 of the Supplemental Material. Many of the recognized structures are members of the northern (leading/trailing) or southern (leading/trailing) arm ...
... number-density contrast. Known over-densities and streams are identified by labels on the maps shown in Fig. 1; locations of these are listed in Table 1 of the Supplemental Material. Many of the recognized structures are members of the northern (leading/trailing) or southern (leading/trailing) arm ...
The Big Bang and Stellar Evolution
... or a planet, or anything else. Since both hydrogen and helium are gases, they are good at spreading out, but not at clumping together. 2 - Careful analysis has revealed that there is not enough matter in gas clouds to produce stars. 3 - There would not be enough time for the gas to reach the current ...
... or a planet, or anything else. Since both hydrogen and helium are gases, they are good at spreading out, but not at clumping together. 2 - Careful analysis has revealed that there is not enough matter in gas clouds to produce stars. 3 - There would not be enough time for the gas to reach the current ...
Metallicity, Age, and Mass of Star Forming Galaxies at z~3
... Aging z>4 exLBG should be visible in the HDF images as red sources. There are no such galaxies. But we do see z>4 LBGs. Where are they at Z~3? Recurrent SF? Just bad luck in The HDF? ...
... Aging z>4 exLBG should be visible in the HDF images as red sources. There are no such galaxies. But we do see z>4 LBGs. Where are they at Z~3? Recurrent SF? Just bad luck in The HDF? ...
Galactic chemical evolution of heavy elements: from Barium to
... As for the r-process, the actual astrophysical environment is still a matter of debate (Woosley et al. 1994; Wheeler, Cowan, & Hillebrandt 1998). It has been recently shown that at least two different supernova sources are required for the synthesis of the r-nuclei below or beyond the neutron magic ...
... As for the r-process, the actual astrophysical environment is still a matter of debate (Woosley et al. 1994; Wheeler, Cowan, & Hillebrandt 1998). It has been recently shown that at least two different supernova sources are required for the synthesis of the r-nuclei below or beyond the neutron magic ...
Chapter 12 Pre-supernova evolution of massive stars
... We have seen that low- and intermediate-mass stars (with masses up to ≈ 8 M⊙ ) develop carbonoxygen cores that become degenerate after central He burning. As a consequence the maximum core temperature reached in these stars is smaller than the temperature required for carbon fusion. During the lates ...
... We have seen that low- and intermediate-mass stars (with masses up to ≈ 8 M⊙ ) develop carbonoxygen cores that become degenerate after central He burning. As a consequence the maximum core temperature reached in these stars is smaller than the temperature required for carbon fusion. During the lates ...
Thermal phase curves of nontransiting terrestrial exoplanets
... objects in terms of mass-radius relationship, some probably being volatile-rich (like GJ1214 b), while some (like Kepler 10b) seem to be dominated by denser material. It is reasonable to assume that large analogs of Mercury with no atmosphere exist within this population, either because they formed ...
... objects in terms of mass-radius relationship, some probably being volatile-rich (like GJ1214 b), while some (like Kepler 10b) seem to be dominated by denser material. It is reasonable to assume that large analogs of Mercury with no atmosphere exist within this population, either because they formed ...
Self-similarity in the chemical evolution of galaxies and the delay
... to actually separate the properties of the old and intermediate age stars on a per galaxy basis. Typical errorbars (precision) on age are 0.2 Gyr and 0.01 dex on [Fe/H] and [α/Fe]1 . The definition of the α-element abundances groups together the elements O, Ne, Mg, Si, S, Ca and Ti (Coelho et al. 20 ...
... to actually separate the properties of the old and intermediate age stars on a per galaxy basis. Typical errorbars (precision) on age are 0.2 Gyr and 0.01 dex on [Fe/H] and [α/Fe]1 . The definition of the α-element abundances groups together the elements O, Ne, Mg, Si, S, Ca and Ti (Coelho et al. 20 ...
The Science case for the UV and optical cameras
... • WSO/UV multicolor UV imaging of unresolved distant stellar systems age evaluation of young stellar populations. • The contribution to the integrated UV light of the main sequence turn off stars make possible the use of UV colors for age determination. For example: ...
... • WSO/UV multicolor UV imaging of unresolved distant stellar systems age evaluation of young stellar populations. • The contribution to the integrated UV light of the main sequence turn off stars make possible the use of UV colors for age determination. For example: ...
FLARESTARSINTHEORIONN EBULAREGION SUMARIO Durante
... observed spectroscopically -obtaining slit spectrograms of about 200 A/mm dispersion and with the equivalent spectral resolving power that Kraft and Greenstein (1969) used in their Pleiades star observations- even during minimum at least the very great majority would show emission lines, especially ...
... observed spectroscopically -obtaining slit spectrograms of about 200 A/mm dispersion and with the equivalent spectral resolving power that Kraft and Greenstein (1969) used in their Pleiades star observations- even during minimum at least the very great majority would show emission lines, especially ...
6. Stellar Spectra
... Stellar classification Saha’s equation stellar classification (C. Payne’s thesis, Harvard 1925) The strengths of selected lines along the spectral sequence. ...
... Stellar classification Saha’s equation stellar classification (C. Payne’s thesis, Harvard 1925) The strengths of selected lines along the spectral sequence. ...
The Universe - the Scientia Review
... Elliptical Galaxies Bright, white galaxies are classified as elliptical. Because of their brightness, we usually can’t see any features in these galaxies. Some elliptical galaxies have only a hundred million stars, while others contain as many as one trillion stars, most of This picture of the M87 g ...
... Elliptical Galaxies Bright, white galaxies are classified as elliptical. Because of their brightness, we usually can’t see any features in these galaxies. Some elliptical galaxies have only a hundred million stars, while others contain as many as one trillion stars, most of This picture of the M87 g ...
Star Formation in Disks: Spiral Arms, Turbulence, and Triggering
... results in the dense gas. Spiral density waves in the stars and stellar bars can do this, as mentioned in the previous section. Among the various sources of ISM energy, we include supernovae, HII regions and stellar winds as stellar sources, and galaxy rotation as an energy source for the magnetic fi ...
... results in the dense gas. Spiral density waves in the stars and stellar bars can do this, as mentioned in the previous section. Among the various sources of ISM energy, we include supernovae, HII regions and stellar winds as stellar sources, and galaxy rotation as an energy source for the magnetic fi ...
Detection of isolated population III stars with the James Webb Space
... emerging from the stellar atmosphere. The region could also break out of the gravitational well of the host halo if the feedback is strong enough (e.g. Kitayama et al. 2004; Whalen et al. 2004). As described by Greif et al. (2009), this dilutes the nebular flux. This could expose more of the purely ...
... emerging from the stellar atmosphere. The region could also break out of the gravitational well of the host halo if the feedback is strong enough (e.g. Kitayama et al. 2004; Whalen et al. 2004). As described by Greif et al. (2009), this dilutes the nebular flux. This could expose more of the purely ...
General Module information
... Explain what is meant by a Hayashi track and sketch such a track on an HR diagram. Explain qualitatively how planetary systems might form. Explain what is meant by the zero age main sequence (ZAMS). Explain in words the evolution of a star on the main sequence and know approximately how the main seq ...
... Explain what is meant by a Hayashi track and sketch such a track on an HR diagram. Explain qualitatively how planetary systems might form. Explain what is meant by the zero age main sequence (ZAMS). Explain in words the evolution of a star on the main sequence and know approximately how the main seq ...
Evolution of the barium abundance in the early Galaxy from a NLTE
... levels and overpopulates the upper ones (this “pumping” is described e.g. in Bruls et al. 1992, or Asplund 2005). The depth of the effective formation of the radiation in b-b transitions changes significantly with the metallicity (and the corresponding barium abundance) of the star (Fig. 3). This exp ...
... levels and overpopulates the upper ones (this “pumping” is described e.g. in Bruls et al. 1992, or Asplund 2005). The depth of the effective formation of the radiation in b-b transitions changes significantly with the metallicity (and the corresponding barium abundance) of the star (Fig. 3). This exp ...
55 Ignacio Negueruela and Amparo Marco
... immediate progenitors of Type II-P SNe, the most frequent type of SN explosion in the local universe (Smartt 2009; Smith et al. 2011). Most of the explosions come from low-mass RSGs, stars with initial masses M∗ 12 M . The lower mass limit for a star to produce an SN has been estimated at ≈8.5+1 ...
... immediate progenitors of Type II-P SNe, the most frequent type of SN explosion in the local universe (Smartt 2009; Smith et al. 2011). Most of the explosions come from low-mass RSGs, stars with initial masses M∗ 12 M . The lower mass limit for a star to produce an SN has been estimated at ≈8.5+1 ...
Massive Stars in the Arches Cluster 12
... photometry, astrometry, equivalent width, and velocity information. The data are interpreted with a wind/atmosphere code to determine stellar temperatures, luminosities, mass-loss rates, and abundances. We have doubled the number of known emission-line stars, and we have also made the first spectros ...
... photometry, astrometry, equivalent width, and velocity information. The data are interpreted with a wind/atmosphere code to determine stellar temperatures, luminosities, mass-loss rates, and abundances. We have doubled the number of known emission-line stars, and we have also made the first spectros ...
Puzzling X-rays from the new colliding wind binary Wolf–Rayet 65
... occurs near periastron, when a greater fraction of the stellar winds collides and the higher pre-shock densities and the lower pre-shock velocities result in stronger radiative cooling. The eclipse occurs immediately after periastron passage when the companion of η Car swings behind the LBV star wit ...
... occurs near periastron, when a greater fraction of the stellar winds collides and the higher pre-shock densities and the lower pre-shock velocities result in stronger radiative cooling. The eclipse occurs immediately after periastron passage when the companion of η Car swings behind the LBV star wit ...
PDF only - at www.arxiv.org.
... should be noted in this respect that the planets HD 47536 b (Fe/H = -0,68, SMA = 1,61 AU) and HD 11755 b (Fe/H = -0,74, SMA = 1,08 AU), at very low metallicities, and unknown in 2005, are located below the ZAPO curve. The only planets in this group which are not compatible with the scenario of the Z ...
... should be noted in this respect that the planets HD 47536 b (Fe/H = -0,68, SMA = 1,61 AU) and HD 11755 b (Fe/H = -0,74, SMA = 1,08 AU), at very low metallicities, and unknown in 2005, are located below the ZAPO curve. The only planets in this group which are not compatible with the scenario of the Z ...
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.