FIRST STELLAR ABUNDANCES IN THE DWARF IRREGULAR
... has been the most frequent approach to modeling chemical evolution of more distant galaxies to date (Matteucci & Tosi 1985). So far, only a very limited number of elements can be examined and quantified when using this approach. The chemical evolution of a galaxy depends on the contributions of all ...
... has been the most frequent approach to modeling chemical evolution of more distant galaxies to date (Matteucci & Tosi 1985). So far, only a very limited number of elements can be examined and quantified when using this approach. The chemical evolution of a galaxy depends on the contributions of all ...
Chemical composition of 90 F and G disk dwarfs
... time was chosen in order to obtain a signal-to-noise ratio of at least 150 over the entire spectral range. Most bright stars have S/N ∼ 200 − 400. Figure 1 shows the spectra in the region of the oxygen triplet for two representative stars HD 142373 and HD 106516A. In addition, the solar flux spectru ...
... time was chosen in order to obtain a signal-to-noise ratio of at least 150 over the entire spectral range. Most bright stars have S/N ∼ 200 − 400. Figure 1 shows the spectra in the region of the oxygen triplet for two representative stars HD 142373 and HD 106516A. In addition, the solar flux spectru ...
Cycles of magnetic activity in solar-type stars. The place of the Sun
... It is well known that the duration of the 11-yr cycle of solar activity (Schwabe cycle) ranges from 7 to 17 years according to a century and a half of direct solar observations. Durations of chromospheric activity cycles, found for 50 stars of late spectral classes (F, G and K), vary from 7 to 20 ye ...
... It is well known that the duration of the 11-yr cycle of solar activity (Schwabe cycle) ranges from 7 to 17 years according to a century and a half of direct solar observations. Durations of chromospheric activity cycles, found for 50 stars of late spectral classes (F, G and K), vary from 7 to 20 ye ...
Sample pages 1 PDF
... the stellar temperatures, colors, luminosity and an indication of mass while the star remains on the main sequence. Louise Mayall and Annie Jump Canon first classified the spectral sequence within the H-R diagram in the early twentieth century at Harvard college observatory. Canon took over the early ...
... the stellar temperatures, colors, luminosity and an indication of mass while the star remains on the main sequence. Louise Mayall and Annie Jump Canon first classified the spectral sequence within the H-R diagram in the early twentieth century at Harvard college observatory. Canon took over the early ...
Weakened magnetic braking as the origin of anomalously
... stars that are older than the Sun. The high-precision, long-baseline light curves from Kepler make such investigations possible. The rotation of a star manifests itself in Kepler data as a periodic modulation in the intensity, as dark starspots rotate into and out of view. Intensity variations due t ...
... stars that are older than the Sun. The high-precision, long-baseline light curves from Kepler make such investigations possible. The rotation of a star manifests itself in Kepler data as a periodic modulation in the intensity, as dark starspots rotate into and out of view. Intensity variations due t ...
The Life of a Star
... de Loore B., Doom, C.: Structure and Evolution of Single and Binary Stars, Kluwer, 1992, contains a basic introduction and a discussion about alternative numerical methods (hereafter abbreviated by dLD) ...
... de Loore B., Doom, C.: Structure and Evolution of Single and Binary Stars, Kluwer, 1992, contains a basic introduction and a discussion about alternative numerical methods (hereafter abbreviated by dLD) ...
arXiv:1705.00964v1 [astro-ph.GA] 2 May 2017
... 2017). Subsequent follow-up with ATCA showed largeamplitude oscillations on a timescale of a few hours, so we now classify it as a (rapid, large-amplitude) IDV source. While considering optical follow-up of PKS1322110, we realised that it lies only 80.5 from Spica (α Vir) — the 16th brightest star i ...
... 2017). Subsequent follow-up with ATCA showed largeamplitude oscillations on a timescale of a few hours, so we now classify it as a (rapid, large-amplitude) IDV source. While considering optical follow-up of PKS1322110, we realised that it lies only 80.5 from Spica (α Vir) — the 16th brightest star i ...
Stars
... Stars can differ from the Sun by : Mass, age , Metallicity, Y Convective core Rotation ...
... Stars can differ from the Sun by : Mass, age , Metallicity, Y Convective core Rotation ...
15_Testbank
... 18) Which of the following persons used the ideas of quantum mechanics to describe why the spectral classification scheme is in order of decreasing temperature? A) Annie Jump Cannon B) Williamina Fleming C) Cecilia Payne-Gaposchkin D) Henry Draper E) Edward Pickering Answer: C 19) Suppose you see tw ...
... 18) Which of the following persons used the ideas of quantum mechanics to describe why the spectral classification scheme is in order of decreasing temperature? A) Annie Jump Cannon B) Williamina Fleming C) Cecilia Payne-Gaposchkin D) Henry Draper E) Edward Pickering Answer: C 19) Suppose you see tw ...
Title: Binary interaction dominates the evolution of massive stars
... Because star cluster dynamics and stellar evolution could have affected the multiplicity properties of only very few of the young O stars in our sample (see supporting online material §A.2), our derived distributions are a good representation of the binary properties at birth. Thus it is safe to con ...
... Because star cluster dynamics and stellar evolution could have affected the multiplicity properties of only very few of the young O stars in our sample (see supporting online material §A.2), our derived distributions are a good representation of the binary properties at birth. Thus it is safe to con ...
Indications for an influence of Hot Jupiters
... is slightly lower than the typical X-ray luminosities found for main sequence field stars of spectral type F and G, (log LX = 28.05[27.12, 28.98] erg s−1 , Schmitt & Liefke (2004)). Its Xray emission therefore suggest an age of ca. 5 Gyr or more. This is consistent with the observation that υ And A ...
... is slightly lower than the typical X-ray luminosities found for main sequence field stars of spectral type F and G, (log LX = 28.05[27.12, 28.98] erg s−1 , Schmitt & Liefke (2004)). Its Xray emission therefore suggest an age of ca. 5 Gyr or more. This is consistent with the observation that υ And A ...
A search for debris disks in the Herschel
... (Covey et al. 2007) and the use of techniques to exclude contaminating background galaxies, such as the inspection of deep K-band images for extended objects and the use of the FIR-radio correlation (Carilli & Yun 1999). Finally, a debris disk search in H-ATLAS is completely serendipitous and carrie ...
... (Covey et al. 2007) and the use of techniques to exclude contaminating background galaxies, such as the inspection of deep K-band images for extended objects and the use of the FIR-radio correlation (Carilli & Yun 1999). Finally, a debris disk search in H-ATLAS is completely serendipitous and carrie ...
Diapositiva 1
... Identification of QSOs (reference frame) Basic stellar parameters for single stars as input for RVS data processing: Log(g),Teff, [Fe/H], Av Derivation of L,R, age ,m using parallaxes (and stellar models) Parametrization of special sources (galaxies…) ...
... Identification of QSOs (reference frame) Basic stellar parameters for single stars as input for RVS data processing: Log(g),Teff, [Fe/H], Av Derivation of L,R, age ,m using parallaxes (and stellar models) Parametrization of special sources (galaxies…) ...
Diapositiva 1
... Identification of QSOs (reference frame) Basic stellar parameters for single stars as input for RVS data processing: Log(g),Teff, [Fe/H], Av Derivation of L,R, age ,m using parallaxes (and stellar models) Parametrization of special sources (galaxies…) Italian contribution: Training data Galaxy simul ...
... Identification of QSOs (reference frame) Basic stellar parameters for single stars as input for RVS data processing: Log(g),Teff, [Fe/H], Av Derivation of L,R, age ,m using parallaxes (and stellar models) Parametrization of special sources (galaxies…) Italian contribution: Training data Galaxy simul ...
Is $^ 6$ Li in metal-poor halo stars produced in situ by solar
... It has been known for many years that the chromospheric and coronal activities of dwarf stars are closely related to their rotation (Kraft 1967). This relationship results from the generation and amplification of surface magnetic fields by a complex dynamo mechanism, whose efficiency depends on the in ...
... It has been known for many years that the chromospheric and coronal activities of dwarf stars are closely related to their rotation (Kraft 1967). This relationship results from the generation and amplification of surface magnetic fields by a complex dynamo mechanism, whose efficiency depends on the in ...
Downloadable Full Text
... galaxies, and extra gas is needed to reproduce their overall metallicity distribution functions8. In contrast, the evidence for a single event in Ret II is based on large [Eu/Fe] and [Ba/Fe] enhancements relative to those measured in stars in the other UFDs. The Eu and Ba trends within Ret II can th ...
... galaxies, and extra gas is needed to reproduce their overall metallicity distribution functions8. In contrast, the evidence for a single event in Ret II is based on large [Eu/Fe] and [Ba/Fe] enhancements relative to those measured in stars in the other UFDs. The Eu and Ba trends within Ret II can th ...
Globular Clusters
... the proto-star to increase its central temperature until the ignition of the first nuclear reactions in the stellar core takes place. The nuclear energy production slows down and eventually stops the contraction. The star reaches a nice equilibrium, balancing energy production and transfer and globa ...
... the proto-star to increase its central temperature until the ignition of the first nuclear reactions in the stellar core takes place. The nuclear energy production slows down and eventually stops the contraction. The star reaches a nice equilibrium, balancing energy production and transfer and globa ...
On the nature of sn stars. I. A detailed abundance study
... process with Stark broadening, without needing another broadening mechanism. The observed line broadening in sn stars seems to be related to the "normal" He line formation that originates in these atmospheres. Key words. Stars: chemically peculiar – Stars: abundances – Stars: late-type ...
... process with Stark broadening, without needing another broadening mechanism. The observed line broadening in sn stars seems to be related to the "normal" He line formation that originates in these atmospheres. Key words. Stars: chemically peculiar – Stars: abundances – Stars: late-type ...
Complete Lecture Notes (pdf file)
... stars are both observed to be 7.5, but their blue magnitudes are B1 = 7.2 and B2 = 8.65. (a) What are the colour indices of the two stars. (b) Which star is the bluer and by what factor is it brighter at blue wavelength. (c) Making reasonable assumptions, deduce as many of the physical properties of ...
... stars are both observed to be 7.5, but their blue magnitudes are B1 = 7.2 and B2 = 8.65. (a) What are the colour indices of the two stars. (b) Which star is the bluer and by what factor is it brighter at blue wavelength. (c) Making reasonable assumptions, deduce as many of the physical properties of ...
2 Statistical properties of a sample of periodically variable B-type supergiants
... The projected rotational velocity, v sin i , was found from the automated tool developed by Sim´on-D´ıaz et al. (2006), which is based on a Fourier method to separate the effects of rotational broadening and macroturbulence (which can be significant in B-type supergiants, cf. Ryans et al. 2002). Thi ...
... The projected rotational velocity, v sin i , was found from the automated tool developed by Sim´on-D´ıaz et al. (2006), which is based on a Fourier method to separate the effects of rotational broadening and macroturbulence (which can be significant in B-type supergiants, cf. Ryans et al. 2002). Thi ...
Ch. 16 - Astro1010
... on an H–R diagram, a pattern begins to form. These are the 80 closest stars to us; note the dashed lines of constant radius. The darkened band is called the main sequence, as this is where most stars are. ...
... on an H–R diagram, a pattern begins to form. These are the 80 closest stars to us; note the dashed lines of constant radius. The darkened band is called the main sequence, as this is where most stars are. ...
Calculating Radial Velocities of Low Mass Eclipsing Binaries
... temperatures directly. By studying eclipsing binary pairs comprising one F, G, or K type star with an M type star, we are able to use what we know about the primary star to learn more about the secondary star. For example, measuring the orbital reflex motion of the primary star, together with the ec ...
... temperatures directly. By studying eclipsing binary pairs comprising one F, G, or K type star with an M type star, we are able to use what we know about the primary star to learn more about the secondary star. For example, measuring the orbital reflex motion of the primary star, together with the ec ...
1 Astrobiologically Interesting Stars within 10
... processes by plate tectonics. Thus the inner habitability edge is defined by loss of water via photolysis and hydrogen escape, with consequent ocean evaporation. The outer edge is defined by the formation of CO2 clouds which cool the planet by lowering its albedo and the atmospheric convective lapse ...
... processes by plate tectonics. Thus the inner habitability edge is defined by loss of water via photolysis and hydrogen escape, with consequent ocean evaporation. The outer edge is defined by the formation of CO2 clouds which cool the planet by lowering its albedo and the atmospheric convective lapse ...
cohen_paris_v2_may2009 - Astronomy at Swarthmore College
... consistent with the predictions of the wind instability model. Photoelectric absorption’s effect on the profile shapes can be used as a mass-loss rate diagnostic: massloss rates are lower than previously thought. ...
... consistent with the predictions of the wind instability model. Photoelectric absorption’s effect on the profile shapes can be used as a mass-loss rate diagnostic: massloss rates are lower than previously thought. ...
Stellar classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Light from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with absorption lines. Each line indicates an ion of a certain chemical element, with the line strength indicating the abundance of that ion. The relative abundance of the different ions varies with the temperature of the photosphere. The spectral class of a star is a short code summarizing the ionization state, giving an objective measure of the photosphere's temperature and density.Most stars are currently classified under the Morgan–Keenan (MK) system using the letters O, B, A, F, G, K, and M, a sequence from the hottest (O type) to the coolest (M type). Each letter class is then subdivided using a numeric digit with 0 being hottest and 9 being coolest (e.g. A8, A9, F0, F1 form a sequence from hotter to cooler). The sequence has been expanded with classes for other stars and star-like objects that do not fit in the classical system, such class D for white dwarfs and class C for carbon stars.In the MK system a luminosity class is added to the spectral class using Roman numerals. This is based on the width of certain absorption lines in the star's spectrum which vary with the density of the atmosphere and so distinguish giant stars from dwarfs. Luminosity class 0 or Ia+ stars for hypergiants, class I stars for supergiants, class II for bright giants, class III for regular giants, class IV for sub-giants, class V for main-sequence stars, class sd for sub-dwarfs, and class D for white dwarfs. The full spectral class for the Sun is then G2V, indicating a main-sequence star with a temperature around 5,800K.