![The extreme ultraviolet and X-ray Sun in Time: High](http://s1.studyres.com/store/data/017870176_1-24288de22779e88dac800a0b2dc02394-300x300.png)
The extreme ultraviolet and X-ray Sun in Time: High
... considered ages). We use additional constraints for pre-mainsequence (PMS) rotation from the ≈2 Myr cluster NGC 6530 (28 stars; Henderson & Stassun 2012) and the ≈12 Myr cluster h Per (117 stars; Moraux et al. 2013). For NGC 6530, the 10th, 50th, and 90th percentiles are at 2.7Ω , 6.2Ω, and 35.1Ω ...
... considered ages). We use additional constraints for pre-mainsequence (PMS) rotation from the ≈2 Myr cluster NGC 6530 (28 stars; Henderson & Stassun 2012) and the ≈12 Myr cluster h Per (117 stars; Moraux et al. 2013). For NGC 6530, the 10th, 50th, and 90th percentiles are at 2.7Ω , 6.2Ω, and 35.1Ω ...
Magnetic cycles of Sun-like stars with different levels of coronal and
... al. 2015 have studied a sample of ∼ 120 000 F, G and K stars from the LAMOST DR1 archive, which is an unprecedentedly large sample for a study of the H&K CaII emission. The δS index was measured for these stars, calculated as the difference between standard S-index and a ’zero’ emission line fitted ...
... al. 2015 have studied a sample of ∼ 120 000 F, G and K stars from the LAMOST DR1 archive, which is an unprecedentedly large sample for a study of the H&K CaII emission. The δS index was measured for these stars, calculated as the difference between standard S-index and a ’zero’ emission line fitted ...
in BRIGHTEST STARS
... distance, estimated a diameter 200 times greater than our sun, and about a quarter of a million times brighter in visible light. Considering its spectral classification (A2), Deneb must have a surface temperature between about 8500 to 9000 kelvins (roughly 14,800 to 15,700 degrees F). ...
... distance, estimated a diameter 200 times greater than our sun, and about a quarter of a million times brighter in visible light. Considering its spectral classification (A2), Deneb must have a surface temperature between about 8500 to 9000 kelvins (roughly 14,800 to 15,700 degrees F). ...
MEarth
... orbital periods much longer than those detected by groundbased transit searches. Gould et al. (2003) point out that missions like COROT and Kepler are much more sensitive to M-dwarf habitable planets than to solar-type habitable planets, if they can be reliably monitor the M dwarfs to faint magnitud ...
... orbital periods much longer than those detected by groundbased transit searches. Gould et al. (2003) point out that missions like COROT and Kepler are much more sensitive to M-dwarf habitable planets than to solar-type habitable planets, if they can be reliably monitor the M dwarfs to faint magnitud ...
Mergers of massive main sequence binaries
... Looking at regions of cluster N 11 in the Large Magellanic Cloud (LMC) (cover page), one immediately notices the presence of many bright blue- and white-colored stars. These stars are among the hottest and most massive stars known in the Universe. In the Hertzsprung-Russel (HR) diagram of this clust ...
... Looking at regions of cluster N 11 in the Large Magellanic Cloud (LMC) (cover page), one immediately notices the presence of many bright blue- and white-colored stars. These stars are among the hottest and most massive stars known in the Universe. In the Hertzsprung-Russel (HR) diagram of this clust ...
1 A Re-appraisal of the Habitability of Planets Around M Dwarf Stars
... as its power source. These same named luminosity classes are also numbered for abbreviation; I, II, III, IV, V runs from Supergiant to dwarf. Our own Sun is spectral type G2 and luminosity class V (or dwarf). Less massive dwarf stars are cool, such as M dwarfs. The length of time a particular star r ...
... as its power source. These same named luminosity classes are also numbered for abbreviation; I, II, III, IV, V runs from Supergiant to dwarf. Our own Sun is spectral type G2 and luminosity class V (or dwarf). Less massive dwarf stars are cool, such as M dwarfs. The length of time a particular star r ...
SGS - SBIG
... before or after capturing the astronomical spectra, without removing the spectrograph from the telescope or disturbing it significantly. We have tried to make a very solid unit, but measuring line position to an accuracy of fractions of a pixel requires great care. For very critical work, such as me ...
... before or after capturing the astronomical spectra, without removing the spectrograph from the telescope or disturbing it significantly. We have tried to make a very solid unit, but measuring line position to an accuracy of fractions of a pixel requires great care. For very critical work, such as me ...
Mn, Cu, and Zn abundances in barium stars and their correlations
... of barium and normal giant stars, and present correlations between abundances contributed to different degrees by the weak-s, mains, and r-processes of neutron capture, between Fe-peak elements and heavy elements. Data from the literature are also considered in order to better study the abundance pat ...
... of barium and normal giant stars, and present correlations between abundances contributed to different degrees by the weak-s, mains, and r-processes of neutron capture, between Fe-peak elements and heavy elements. Data from the literature are also considered in order to better study the abundance pat ...
1998 - Universitäts-Sternwarte München
... or the very spectacular supernova events. Nowadays, it is therefore no surprise that the ancient stars of the Galactic halo are found to be metal-poor objects – as opposed to the understanding when they were first analyzed in the 1950s. Interestingly, these stars also reveal a very different kinemat ...
... or the very spectacular supernova events. Nowadays, it is therefore no surprise that the ancient stars of the Galactic halo are found to be metal-poor objects – as opposed to the understanding when they were first analyzed in the 1950s. Interestingly, these stars also reveal a very different kinemat ...
The Final Version of the White Paper is available.
... search for solar system analogues is still on going, the first spectra of exoplanets have been taken, signalling the shift from an era of discovery to one of physical and chemical characterization. This will eventually lead to the remote analysis of planet atmospheres with the ultimate goal of life ...
... search for solar system analogues is still on going, the first spectra of exoplanets have been taken, signalling the shift from an era of discovery to one of physical and chemical characterization. This will eventually lead to the remote analysis of planet atmospheres with the ultimate goal of life ...
Examining the M67 Classification as an Open Cluster
... mvis vs. B - V , diagram (or the HR diagram) for M67, based on our observations. Each dot denotes a star. The purple color indicates the positions of the main sequence stars. The red color indicates the positions of the horizontal branch stars. The yellow color indicates the positions of the gia ...
... mvis vs. B - V , diagram (or the HR diagram) for M67, based on our observations. Each dot denotes a star. The purple color indicates the positions of the main sequence stars. The red color indicates the positions of the horizontal branch stars. The yellow color indicates the positions of the gia ...
Statistical analysis of stellar evolution
... separate out groups of stars powered by different physical processes and at different stages of their lives. These groups include the main sequence, so named for its dominant position in a CMD, the evolved red giants, and the even older white dwarfs. Today the physical processes that govern stellar ...
... separate out groups of stars powered by different physical processes and at different stages of their lives. These groups include the main sequence, so named for its dominant position in a CMD, the evolved red giants, and the even older white dwarfs. Today the physical processes that govern stellar ...
Dynamical Mass Measurements of Pre-Main
... basic theoretical expectations (see Fig. 1). The fact that 2M0535-05 comprises BDs that are both large and luminous — and even simply that they are of M spectral type — is a testament to the generally good predictive power of current theoretical models of young BDs. At the same time, there is a high ...
... basic theoretical expectations (see Fig. 1). The fact that 2M0535-05 comprises BDs that are both large and luminous — and even simply that they are of M spectral type — is a testament to the generally good predictive power of current theoretical models of young BDs. At the same time, there is a high ...
Astronomy and Astrophysics 336, 972, 1998
... stages should be made whenever possible. Therefore, we chose a single main-sequence star that is somewhat cooler than the Sun as a target for repeated Doppler imaging, but we emphasize that the Doppler-imaging technique per se requires a much more rapidly rotating star than the Sun and our target, w ...
... stages should be made whenever possible. Therefore, we chose a single main-sequence star that is somewhat cooler than the Sun as a target for repeated Doppler imaging, but we emphasize that the Doppler-imaging technique per se requires a much more rapidly rotating star than the Sun and our target, w ...
Abstracts - Physics of Evolved Stars 2015
... During the past decade, an increasing number of observations have shown that, at least at some points, the mass-loss rate of red supergiants (RSG) could be significantly higher than the standard one, usually used in stellar evolution code. In this talk, I will show how an increased mass-loss rate du ...
... During the past decade, an increasing number of observations have shown that, at least at some points, the mass-loss rate of red supergiants (RSG) could be significantly higher than the standard one, usually used in stellar evolution code. In this talk, I will show how an increased mass-loss rate du ...
Chapter 16--Properties of Stars
... century, humans classified stars primarily by their brightness and location in our sky. The names of the brightest stars within each constellation still bear Greek letters designating their order of brightness. For example, the brightest star in the constellation Centaurus is Alpha Centauri, the sec ...
... century, humans classified stars primarily by their brightness and location in our sky. The names of the brightest stars within each constellation still bear Greek letters designating their order of brightness. For example, the brightest star in the constellation Centaurus is Alpha Centauri, the sec ...
Spectral Matching for Elemental Abundances of Evolved Stars of Globular Clusters
... oxygen-rich or oxygen-poor. From this a catalogue of abundances of iron, carbon and barium of 848 giant branch stars were determined, of which 557 also had well-defined nitrogen abundances. k-means clustering analysis was used to group the stars in ω Cen into four homogeneous groups based upon these ...
... oxygen-rich or oxygen-poor. From this a catalogue of abundances of iron, carbon and barium of 848 giant branch stars were determined, of which 557 also had well-defined nitrogen abundances. k-means clustering analysis was used to group the stars in ω Cen into four homogeneous groups based upon these ...
5 - White Dwarfs - University of Texas Astronomy
... described many times now, nuclear ignition under conditions where the star is supported by the quantum pressure is very unstable. Ignition of carbon under these conditions would lead to a violent explosion. This explosion would occur in a star devoid of hydrogen, save perhaps for a negligibly thin l ...
... described many times now, nuclear ignition under conditions where the star is supported by the quantum pressure is very unstable. Ignition of carbon under these conditions would lead to a violent explosion. This explosion would occur in a star devoid of hydrogen, save perhaps for a negligibly thin l ...
CORONAL EVOLUTION OF THE SUN IN TIME: HIGH
... bright chromospheric plages, chromospheric emission lines, and coronal radio and X-ray emissions. The coronal emissions display the largest range of variation in response to the surface magnetic activity level. Whereas starspots may cover a few percent of the photosphere of the most active solar ana ...
... bright chromospheric plages, chromospheric emission lines, and coronal radio and X-ray emissions. The coronal emissions display the largest range of variation in response to the surface magnetic activity level. Whereas starspots may cover a few percent of the photosphere of the most active solar ana ...
Evidence for the Tidal Destruction of Hot Jupiters by Subgiant Stars
... Figure 2. Galactic U V W kinematics of subgiant stars that host exoplanets discovered with the radial-velocity technique. In each panel, we plot the U V W space motions of the subgiant sample as blue points and the density of points in a control sample selected from the Hipparcos catalog as the back ...
... Figure 2. Galactic U V W kinematics of subgiant stars that host exoplanets discovered with the radial-velocity technique. In each panel, we plot the U V W space motions of the subgiant sample as blue points and the density of points in a control sample selected from the Hipparcos catalog as the back ...
Behaviour of elements from lithium to europium in stars with and
... with Teff lower than 5000 K, we used only the trigonometric parallax method. The microturbulence velocity Vt was derived providing that the iron abundance log A(Fe) obtained from Fe I lines was not correlated with the equivalent width, EW. The adopted metallicity value [Fe/H] was the iron abundance ...
... with Teff lower than 5000 K, we used only the trigonometric parallax method. The microturbulence velocity Vt was derived providing that the iron abundance log A(Fe) obtained from Fe I lines was not correlated with the equivalent width, EW. The adopted metallicity value [Fe/H] was the iron abundance ...
1. INTRODUCTION
... can be considered as single X-ray sources. Some stars in the sample are detected or known binary systems, in which only one of the components is believed to contribute signiÐcantly to the EUV and X-ray emitted radiation. If a star was observed several times (more than a few days apart), we considere ...
... can be considered as single X-ray sources. Some stars in the sample are detected or known binary systems, in which only one of the components is believed to contribute signiÐcantly to the EUV and X-ray emitted radiation. If a star was observed several times (more than a few days apart), we considere ...
Binarity in carbon-enhanced metal-poor stars
... The large class of CEMP-s stars is thought to obtain their overabundant carbon and s-process elements from a companion star that has gone through the asymptotic giant branch (AGB) phase and deposited large amounts of newly formed carbon and s-process material on its neighbour. Strong evidence in fav ...
... The large class of CEMP-s stars is thought to obtain their overabundant carbon and s-process elements from a companion star that has gone through the asymptotic giant branch (AGB) phase and deposited large amounts of newly formed carbon and s-process material on its neighbour. Strong evidence in fav ...
astro-ph/0301519 PDF
... discovered a few examples of such very hot stars and a detailed survey of the central stars of old PN has revealed a number of others (see Napiwotzki 1999). To date, all the studies of these objects have utilized pure H models to determine Teff and log g and have not taken into account the possible ...
... discovered a few examples of such very hot stars and a detailed survey of the central stars of old PN has revealed a number of others (see Napiwotzki 1999). To date, all the studies of these objects have utilized pure H models to determine Teff and log g and have not taken into account the possible ...
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.