![Consistent metallicity scale for cool dwarfs and giants](http://s1.studyres.com/store/data/016789023_1-b20350570b6d517cffd4a74b4e28adac-300x300.png)
Consistent metallicity scale for cool dwarfs and giants
... produced by systematic errors in the analysis. We aim to ascertain a methodology capable of producing a consistent metallicity scale for giants and dwarfs. Methods. To achieve that, we analyzed giants and dwarfs in the Hyades open cluster, under the assumption that they share the same chemical compo ...
... produced by systematic errors in the analysis. We aim to ascertain a methodology capable of producing a consistent metallicity scale for giants and dwarfs. Methods. To achieve that, we analyzed giants and dwarfs in the Hyades open cluster, under the assumption that they share the same chemical compo ...
Determination of accurate stellar radial
... ELODIE (Baranne et al. 1996) is an échelle spectrometer physically located in a coudé room at the 1.93 m telescope at Observatoire de Haute-Provence (OHP). For this programme, the spectrometer was fed via one optical fibre from the Cassegrain focus. The instrument FWHM is '7.2 km s−1 , correspondi ...
... ELODIE (Baranne et al. 1996) is an échelle spectrometer physically located in a coudé room at the 1.93 m telescope at Observatoire de Haute-Provence (OHP). For this programme, the spectrometer was fed via one optical fibre from the Cassegrain focus. The instrument FWHM is '7.2 km s−1 , correspondi ...
The 2008 RBSE Journal - National Optical Astronomy Observatory
... A Double Radio Source Associated with a Galactic Nucleus (DRAGN) is a radio source that is produced by jets produced by active galactic nucleus that is not in the Milky Way. This happens when an accretion disk forms around a black hole and spins, converts gravitational and rotational energy into exc ...
... A Double Radio Source Associated with a Galactic Nucleus (DRAGN) is a radio source that is produced by jets produced by active galactic nucleus that is not in the Milky Way. This happens when an accretion disk forms around a black hole and spins, converts gravitational and rotational energy into exc ...
a wide-field survey for variable stars
... 2.3.5 The effect of starspots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.7 The effect of rotation to a 20M¯ star with a Z=0.02 at ZAMS . . . . . . 2.3.6 Distribution of calcium on the surface of the Ap star HR 3831 . . . . . . . 2.4.1 The butterfly diagram . . . . . . . . . . . . ...
... 2.3.5 The effect of starspots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.7 The effect of rotation to a 20M¯ star with a Z=0.02 at ZAMS . . . . . . 2.3.6 Distribution of calcium on the surface of the Ap star HR 3831 . . . . . . . 2.4.1 The butterfly diagram . . . . . . . . . . . . ...
The spectroscopic Hertzsprung
... that the absolute brightnesses, i.e., the distances, are required to properly order the stars in the HR diagram. Order can also be achieved for stars in star clusters where the distance may still be unknown, but the distances of all stars are roughly equal, in what we now call color-magnitude diagra ...
... that the absolute brightnesses, i.e., the distances, are required to properly order the stars in the HR diagram. Order can also be achieved for stars in star clusters where the distance may still be unknown, but the distances of all stars are roughly equal, in what we now call color-magnitude diagra ...
Chapter 17--Star Stuff
... itself. The clouds that form stars tend to be quite cold, typically only 10–30 K. (Recall that 0 K is absolute zero, and temperatures on Earth are around 300 K.) They also tend to be quite dense compared to the rest of the gas between the stars, although they would qualify as a superb vacuum by eart ...
... itself. The clouds that form stars tend to be quite cold, typically only 10–30 K. (Recall that 0 K is absolute zero, and temperatures on Earth are around 300 K.) They also tend to be quite dense compared to the rest of the gas between the stars, although they would qualify as a superb vacuum by eart ...
The first photometric analysis of the overcontact binary MQ UMa with
... The equation is derived from a total sample of 141 contact binaries, whose spectral type ranges from A2V to K5V, and has a period from 0.2211 days to 1.1318 days. The sample has covered nearly all kinds of W UMa type contact binaries which means it is appropriate to MQ UMa. The period of MQ UMa is 0 ...
... The equation is derived from a total sample of 141 contact binaries, whose spectral type ranges from A2V to K5V, and has a period from 0.2211 days to 1.1318 days. The sample has covered nearly all kinds of W UMa type contact binaries which means it is appropriate to MQ UMa. The period of MQ UMa is 0 ...
The Pleiades in the Salle des Taureaux", Grotte de Lascaux
... circles the position at the epoch -15300. The proper motions of the stars are shown by connecting lines between the black and white circles. The shifting by reason of the precession of equinoxes is taken into account. Software Hipparcos 2000.0 for the Atari ST 1040 from ANDREAS KAMMERER, Karlsruhe, ...
... circles the position at the epoch -15300. The proper motions of the stars are shown by connecting lines between the black and white circles. The shifting by reason of the precession of equinoxes is taken into account. Software Hipparcos 2000.0 for the Atari ST 1040 from ANDREAS KAMMERER, Karlsruhe, ...
Starburst Galaxies - Beck-Shop
... The reader may however find the following mnemonic useful: Oh Be A Fine Girl/Guy Kiss Me Each of these major classes is sub-divided into 10, with each subdivision labeled by a number from 0 to 9. The Sun thus has a spectral class of G2; Sirius (α CMa) is A1 while Antares (α Sco) is M2. The hottest s ...
... The reader may however find the following mnemonic useful: Oh Be A Fine Girl/Guy Kiss Me Each of these major classes is sub-divided into 10, with each subdivision labeled by a number from 0 to 9. The Sun thus has a spectral class of G2; Sirius (α CMa) is A1 while Antares (α Sco) is M2. The hottest s ...
Element Segregation in Low Metallicity Stars and the Primordial
... which depends on the effective temperature, the age and the metallicity of the stars. This prediction is in contradiction with the observations of the lithium plateau in Pop II stars. However, as discussed above, the lithium profiles in the standard models present a maximum (Limax ) which remains re ...
... which depends on the effective temperature, the age and the metallicity of the stars. This prediction is in contradiction with the observations of the lithium plateau in Pop II stars. However, as discussed above, the lithium profiles in the standard models present a maximum (Limax ) which remains re ...
Classification of Variable Stars
... V1668 Cyg. These are stars in constellations for which all of the letter combinations have been exhausted. (i.e. V746 Oph is the 746th variable to be discovered in Ophiuchus.) Variable star names are determined by a committee appointed by the International Astronomical Union (I.A.U.). The assignment ...
... V1668 Cyg. These are stars in constellations for which all of the letter combinations have been exhausted. (i.e. V746 Oph is the 746th variable to be discovered in Ophiuchus.) Variable star names are determined by a committee appointed by the International Astronomical Union (I.A.U.). The assignment ...
Impact of atmospheric refraction: How deeply can we probe exo
... papers (Garcı́a Muñoz & Mills 2012; Garcı́a Muñoz et al. 2012; Bétrémieux & Kaltenegger 2013; Rodler & López-Morales 2014; Misra et al. 2014). At the top of the atmosphere, the ray from the star is undeflected. As the impact parameter of the rays decreases, the deflection of the rays increases. ...
... papers (Garcı́a Muñoz & Mills 2012; Garcı́a Muñoz et al. 2012; Bétrémieux & Kaltenegger 2013; Rodler & López-Morales 2014; Misra et al. 2014). At the top of the atmosphere, the ray from the star is undeflected. As the impact parameter of the rays decreases, the deflection of the rays increases. ...
The connection between stellar activity cycles and magnetic field
... the number of ZDI maps one is able to produce over an activity cycle will be much more sparse when compared to the number of chromospheric observations. Therefore, it is useful to study activity cycles with chromospheric data in conjunction with the ZDI technique. There are now numerous stars that h ...
... the number of ZDI maps one is able to produce over an activity cycle will be much more sparse when compared to the number of chromospheric observations. Therefore, it is useful to study activity cycles with chromospheric data in conjunction with the ZDI technique. There are now numerous stars that h ...
Stellar evolution - Statistical Physics Group
... stars belonged. Originally in the Harvard classification the classes labelled A, B, C, ., , were principally characterized by decreasing strength of the hydrogen absorption lines; subsequently Saha showed that there was a more natural ordering in which the succession of spectral types was mainly cha ...
... stars belonged. Originally in the Harvard classification the classes labelled A, B, C, ., , were principally characterized by decreasing strength of the hydrogen absorption lines; subsequently Saha showed that there was a more natural ordering in which the succession of spectral types was mainly cha ...
Distance determination for RAVE stars using stellar models
... the effective temperature and response function (‘shape’) of a colour filter since the shape of the spectrum is completely determined by the Planck curve. From these absolute magnitudes, colour indices can be constructed, which is defined as the difference between the magnitudes in two different ban ...
... the effective temperature and response function (‘shape’) of a colour filter since the shape of the spectrum is completely determined by the Planck curve. From these absolute magnitudes, colour indices can be constructed, which is defined as the difference between the magnitudes in two different ban ...
Chapter 5 Theory of Stellar Evolution
... How are we to reconcile these impediments to gravitational contraction with the fact that stars exits? One can use the rotational and magnetic energies against one another. A moderate magnetic field of a spinning object will cause a great deal of angular momentum per unit mass to be lost by a star t ...
... How are we to reconcile these impediments to gravitational contraction with the fact that stars exits? One can use the rotational and magnetic energies against one another. A moderate magnetic field of a spinning object will cause a great deal of angular momentum per unit mass to be lost by a star t ...
exploring anticorrelations and light element variations
... entire wavelength region covered by the APOGEE spectrograph. This is different from most literature publications that use Fe lines to track metallicity in a stellar atmosphere. We use [Fe/H] in this paper whenever we refer to metallicity presented here, because we use Fe I lines to measure it. For t ...
... entire wavelength region covered by the APOGEE spectrograph. This is different from most literature publications that use Fe lines to track metallicity in a stellar atmosphere. We use [Fe/H] in this paper whenever we refer to metallicity presented here, because we use Fe I lines to measure it. For t ...
Luminosities and mass-loss rates of SMC and LMC AGB stars and
... Speck et al. also proposed that graphite rather then amorphous carbon dominates the dust, at least in the C-stars with extreme mass-loss rates they considered. Only one set of optical constants seems to have been published for graphite, those by Draine & Lee (1984), as used by e.g. Volk et al. (1992 ...
... Speck et al. also proposed that graphite rather then amorphous carbon dominates the dust, at least in the C-stars with extreme mass-loss rates they considered. Only one set of optical constants seems to have been published for graphite, those by Draine & Lee (1984), as used by e.g. Volk et al. (1992 ...
Telluric Line Removal in Astrophysical Spectroscopy
... dust. Starlight passing through this material will be scattered according to Raleigh scattering, and will produce absorption features within the stellar spectrum. An A-type star may be chosen that is not reddened significantly to avoid this problem. Although the spectrum of an A-type star is essenti ...
... dust. Starlight passing through this material will be scattered according to Raleigh scattering, and will produce absorption features within the stellar spectrum. An A-type star may be chosen that is not reddened significantly to avoid this problem. Although the spectrum of an A-type star is essenti ...
SAGE_prop
... Beyond the provision of light and heat, the correlation between the occurrence of sunspots and displays of spectacular aurora gave us early clues to the existence of a chain of events linking solar phenomena to a terrestrial response. Proctor in 1870 described an event where at a station in Norway “ ...
... Beyond the provision of light and heat, the correlation between the occurrence of sunspots and displays of spectacular aurora gave us early clues to the existence of a chain of events linking solar phenomena to a terrestrial response. Proctor in 1870 described an event where at a station in Norway “ ...
Open clusters in the Third Galactic Quadrant III. Alleged binary
... Aims. We aim to determine accurate distances and ages of eight open clusters in order to: (1) assess their possible binarity (2) provide probes to trace the structure of the Third Galactic Quadrant. Methods. Cluster reddenings, distances, ages and metallicities are derived from ZAMS and isochrone fi ...
... Aims. We aim to determine accurate distances and ages of eight open clusters in order to: (1) assess their possible binarity (2) provide probes to trace the structure of the Third Galactic Quadrant. Methods. Cluster reddenings, distances, ages and metallicities are derived from ZAMS and isochrone fi ...
Archaeoastronomical Study of the Main Pyramids of Giza
... Theory” (OCT). According to these authors, a perfect coincidence would exist between the mutual positions of the three stars of the Orion Belt and those of the main Giza pyramids, so that the latter would represent the monumental reproduction on the ground of that important asterism (see Bauval, 200 ...
... Theory” (OCT). According to these authors, a perfect coincidence would exist between the mutual positions of the three stars of the Orion Belt and those of the main Giza pyramids, so that the latter would represent the monumental reproduction on the ground of that important asterism (see Bauval, 200 ...
The Gould Belt
... nebulae of the Gould belt. These are dwarfs in late spectral classes with masses of ≈ 1M⊙ and ages of several million years that have not reached the Main sequence stage. Stars have also been identified in terms of their emission in the HJ line, their lithium abundance, xray emission, position in the ...
... nebulae of the Gould belt. These are dwarfs in late spectral classes with masses of ≈ 1M⊙ and ages of several million years that have not reached the Main sequence stage. Stars have also been identified in terms of their emission in the HJ line, their lithium abundance, xray emission, position in the ...
Astronomy Astrophysics First detection of the field star overdensity in the Perseus... &
... and newborn stars) seems to peak near the inner arm edge while the stars are all over the arms. Furthermore, to analyze the interaction between the arm and the stellar component, the selected B4–A1 stellar tracers are young enough so their intrinsic velocity is still small, so that their response to ...
... and newborn stars) seems to peak near the inner arm edge while the stars are all over the arms. Furthermore, to analyze the interaction between the arm and the stellar component, the selected B4–A1 stellar tracers are young enough so their intrinsic velocity is still small, so that their response to ...
Neutron star masses: dwarfs, giants and neighbors
... We assume that the rapid rotation of the core of a collapsing star can be explained by tidal synchronization in a very close binary. The calculated rate of formation of rapidly rotating neutron stars is qualitatively consistent with estimates of the formation rate of magnetars. However, our analysis ...
... We assume that the rapid rotation of the core of a collapsing star can be explained by tidal synchronization in a very close binary. The calculated rate of formation of rapidly rotating neutron stars is qualitatively consistent with estimates of the formation rate of magnetars. However, our analysis ...
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.