Astronomy Astrophysics + Infrared identification of 2XMM J191043.4
... 0.5 kpc. On the other hand, Brγ is the most prominent feature in Be stars in the K band, while He i 2.058 μm is found in early-type Be stars, up to B2.5 (Clark and Steele 2000). Therefore, assuming a B0V star, the intrinsic colour would be (H − K)0 = −0.05 (Ducati et al. 2001) and E(H−K) = 1.27, als ...
... 0.5 kpc. On the other hand, Brγ is the most prominent feature in Be stars in the K band, while He i 2.058 μm is found in early-type Be stars, up to B2.5 (Clark and Steele 2000). Therefore, assuming a B0V star, the intrinsic colour would be (H − K)0 = −0.05 (Ducati et al. 2001) and E(H−K) = 1.27, als ...
The observed distribution of spectroscopic binaries from the Anglo
... In the search for an orbital solution, periods are initially identified via Lomb–Scargle periodogram analysis (Lomb 1976; Scargle 1982). Orbital solutions are plotted in Fig. 1 and summarized in Table 2 (i and ii). Where the RV data have a monotonic variation, or only one extremum occurs without any ...
... In the search for an orbital solution, periods are initially identified via Lomb–Scargle periodogram analysis (Lomb 1976; Scargle 1982). Orbital solutions are plotted in Fig. 1 and summarized in Table 2 (i and ii). Where the RV data have a monotonic variation, or only one extremum occurs without any ...
Circumstellar medium around rotating massive stars at solar metallicity
... identical to a spherical mesh with an equidistant angle discretisation and a logarithmic radial discretisation. With this mesh, the self-similar evolution phase of the bubble is well recovered, demonstrating the suitability of the chosen approach for the astrophysical problem under consideration (se ...
... identical to a spherical mesh with an equidistant angle discretisation and a logarithmic radial discretisation. With this mesh, the self-similar evolution phase of the bubble is well recovered, demonstrating the suitability of the chosen approach for the astrophysical problem under consideration (se ...
Formation of high-field magnetic white dwarfs from common envelopes
... two classes: AM Herculis (AM Her) (polars) and DQ Herculis (DQ Her) (intermediate polars). For reviews on AM Her and DQ Her systems, see refs. 9 and 10. Generally, AM Her systems are those in which both components of the binary are synchronously rotating at the orbital period. In this scenario, the ...
... two classes: AM Herculis (AM Her) (polars) and DQ Herculis (DQ Her) (intermediate polars). For reviews on AM Her and DQ Her systems, see refs. 9 and 10. Generally, AM Her systems are those in which both components of the binary are synchronously rotating at the orbital period. In this scenario, the ...
Metallicity and Planet Formation: Models
... All planet formation theorists agree that terrestrial planets form by the collisional accumulation of solids composed of heavy elements in the inner regions of protoplanetary disks (e.g., Wetherill 1996). This process begins with the sedimentation of dust grains to the disk midplane and their growth ...
... All planet formation theorists agree that terrestrial planets form by the collisional accumulation of solids composed of heavy elements in the inner regions of protoplanetary disks (e.g., Wetherill 1996). This process begins with the sedimentation of dust grains to the disk midplane and their growth ...
Final Paper Template for the 5th Southeast Asian Forum
... models that use Scalo IMF. This can be happened because Kroupa IMF gives more massive stars which evolve and suffer heavy mass-loss during the first stage of cluster evolution. Fast dissolution also happen in models with low density parameter W0 = 4 that reach OCR stage at age less than 1 Gyr. On th ...
... models that use Scalo IMF. This can be happened because Kroupa IMF gives more massive stars which evolve and suffer heavy mass-loss during the first stage of cluster evolution. Fast dissolution also happen in models with low density parameter W0 = 4 that reach OCR stage at age less than 1 Gyr. On th ...
Large distance of epsilon Aurigae from interstellar
... Unfortunately, none of these additional DIBs are covered by our spectra. The limited spectral resolution of our spectra may imply that our EWs only represent a lower limit to the true EW of the 6613 DIB but in the light of the above-mentioned studies we do believe that with a homogeneous series of ...
... Unfortunately, none of these additional DIBs are covered by our spectra. The limited spectral resolution of our spectra may imply that our EWs only represent a lower limit to the true EW of the 6613 DIB but in the light of the above-mentioned studies we do believe that with a homogeneous series of ...
– 1 – 1. Discrete Spectral Lines – DRAFT, INCOMPLETE
... straightforward to handle; see, for example, chapter 18 of Gray’s book (3rd edition). One divides the visible disk of the star into strips parallel to the axis of rotation, so that each strip has a constant rotational velocity with a wavelength shift from the nominal line center λ0 of ∆λ = λ0 ω x/c, ...
... straightforward to handle; see, for example, chapter 18 of Gray’s book (3rd edition). One divides the visible disk of the star into strips parallel to the axis of rotation, so that each strip has a constant rotational velocity with a wavelength shift from the nominal line center λ0 of ∆λ = λ0 ω x/c, ...
Galaxy Independent Study Assignment
... spirals, barred spirals, or ellipticals. A spiral galaxy consists of a flattened disk containing spiral (pinwheel-shaped) arms, a bulge at its center, and a halo. Spiral galaxies have a variety of shapes, and they are classified according to the size of the bulge and the tightness and appearance of ...
... spirals, barred spirals, or ellipticals. A spiral galaxy consists of a flattened disk containing spiral (pinwheel-shaped) arms, a bulge at its center, and a halo. Spiral galaxies have a variety of shapes, and they are classified according to the size of the bulge and the tightness and appearance of ...
They might be giants: luminosity class, planet frequency, and planet
... mean g − r vs. J − H loci for KOIs and Kepler stars without identified transits. They find a significant difference between the g − r colors of the two populations for stars with J − H ≈ 0.62, corresponding to late Ktype stars. Based on stellar models, SL11 argue that the late-type KOIs are ≃ 0.2 de ...
... mean g − r vs. J − H loci for KOIs and Kepler stars without identified transits. They find a significant difference between the g − r colors of the two populations for stars with J − H ≈ 0.62, corresponding to late Ktype stars. Based on stellar models, SL11 argue that the late-type KOIs are ≃ 0.2 de ...
The impact of rotation on the line profiles of Wolf
... Potsdam Wolf-Rayet (PoWR) model atmosphere code potentially imply the existence of rapidly rotating WR stars. Hamann et al. (2006) performed a flux-convolution with a rotation profile (e.g. Unsöld 1955) in order to reproduce the broad and round emission lines of the Galactic WN2 star WR 2. Hainich e ...
... Potsdam Wolf-Rayet (PoWR) model atmosphere code potentially imply the existence of rapidly rotating WR stars. Hamann et al. (2006) performed a flux-convolution with a rotation profile (e.g. Unsöld 1955) in order to reproduce the broad and round emission lines of the Galactic WN2 star WR 2. Hainich e ...
Paper II - van Werkhoven, Kenworthy and Mamajek (2014)
... where P0 is the nominal period and Ṗ the time-derivative of the period. This model is fitted to the data using the Nelder–Mead fitting algorithm (Nelder & Mead 1965). Our analysis shows that the bestfitting periods and their amplitudes differ significantly from year to year (see Table 1). Furthermo ...
... where P0 is the nominal period and Ṗ the time-derivative of the period. This model is fitted to the data using the Nelder–Mead fitting algorithm (Nelder & Mead 1965). Our analysis shows that the bestfitting periods and their amplitudes differ significantly from year to year (see Table 1). Furthermo ...
The Milky Way: Cartoon
... Finding MACHOS we can’t see Recap: Gravitational Lensing: positions of background stars will change when observed along a sight-line near a massive object. Like the sun. Observation of apparent change in star positions during a solar eclipse (when we can see close to the sun) in 1919 was a first pr ...
... Finding MACHOS we can’t see Recap: Gravitational Lensing: positions of background stars will change when observed along a sight-line near a massive object. Like the sun. Observation of apparent change in star positions during a solar eclipse (when we can see close to the sun) in 1919 was a first pr ...
“End-of-the-Line” W UMa Eclipsing Binary V523
... they manage to coexist with remarkable stability. Overcontact binaries are found across almost the entire range of stellar spectral types, from the hot ...
... they manage to coexist with remarkable stability. Overcontact binaries are found across almost the entire range of stellar spectral types, from the hot ...
ppt - Serbian Virtual Observatory
... Flare activity: - a very quick increase of the brightness and a decline from maximum to minimum for some minutes up to some hours; - a common characteristic in the early evolution of all red dwarf stars. Belonging: - to the population of young stellar clusters and associations. Flare-like activity: ...
... Flare activity: - a very quick increase of the brightness and a decline from maximum to minimum for some minutes up to some hours; - a common characteristic in the early evolution of all red dwarf stars. Belonging: - to the population of young stellar clusters and associations. Flare-like activity: ...
Document
... are large but the mean trends are reliable. Evan Kirby has been developing a technique for determining alpha and Fe for DEIMOS-Keck spectra in a large number of dSph galaxies. This technique is growing in sophistication and will soon measure individual abundances. ...
... are large but the mean trends are reliable. Evan Kirby has been developing a technique for determining alpha and Fe for DEIMOS-Keck spectra in a large number of dSph galaxies. This technique is growing in sophistication and will soon measure individual abundances. ...
The AcroCoRoT objectives (10 min) - IAG-Usp
... of rotation during stellar evolution from PMS to PostMS Giants? How does magnetic breaking affect rotation ? What physical processes control the generation of magnetic field? What type(s) of dynamo is at play in stellar interiors? Do we correctly understand and model surface structures such as spots ...
... of rotation during stellar evolution from PMS to PostMS Giants? How does magnetic breaking affect rotation ? What physical processes control the generation of magnetic field? What type(s) of dynamo is at play in stellar interiors? Do we correctly understand and model surface structures such as spots ...
they might be giants: luminosity class, planet occurrence, and planet
... some target stars are actually larger or even giant stars, then planets are less likely to be detected in that sample, which means that the most likely occurrence rate of those planets is higher. For M dwarf stars in general, and particularly for the coolest Kepler target stars, parameters such as r ...
... some target stars are actually larger or even giant stars, then planets are less likely to be detected in that sample, which means that the most likely occurrence rate of those planets is higher. For M dwarf stars in general, and particularly for the coolest Kepler target stars, parameters such as r ...
Evolution and colors of helium-core white dwarf stars with high
... captured the attention of researchers since Kippenhahn et al. (1967) suggested that these stars could be the natural result of substantial mass loss from low-mass red giant stars filling their Roche lobes in binary systems. Later, Webbink (1975) was the first to show that for masses greater than 0.1 ...
... captured the attention of researchers since Kippenhahn et al. (1967) suggested that these stars could be the natural result of substantial mass loss from low-mass red giant stars filling their Roche lobes in binary systems. Later, Webbink (1975) was the first to show that for masses greater than 0.1 ...
as a PDF - Research Database
... nuclear processed material to be transported to the stellar surface (e.g., carbon and s-process elements such as lithium and technetium). AGB stars within a certain mass range can thus be turned into carbon stars when the photospheric carbon-tooxygen abundance ratio exceeds unity (Bessell et al. 198 ...
... nuclear processed material to be transported to the stellar surface (e.g., carbon and s-process elements such as lithium and technetium). AGB stars within a certain mass range can thus be turned into carbon stars when the photospheric carbon-tooxygen abundance ratio exceeds unity (Bessell et al. 198 ...
Lecture 2. Thermal evolution and surface emission of neutron stars
... prototypes of a different subpopulation of NSs born with low magnetic field (< few 1011 G) and relatively long spin periods (few tenths of a second). These NSs are relatively hot, and probably not very rare. Surprisingly, we do not see objects of this type in our vicinity. In the solar neighbourhood ...
... prototypes of a different subpopulation of NSs born with low magnetic field (< few 1011 G) and relatively long spin periods (few tenths of a second). These NSs are relatively hot, and probably not very rare. Surprisingly, we do not see objects of this type in our vicinity. In the solar neighbourhood ...
the red supergiant content of m31
... stars lose most of their hydrogen-rich envelopes and exploded instead as type II-L or even type Ib supernovae. The validity of this resolution rests on the assumption that the RSG mass-loss rates have been seriously underestimated. Meynet et al. (2015) and Georgy et al. (2015) proposed a novel way o ...
... stars lose most of their hydrogen-rich envelopes and exploded instead as type II-L or even type Ib supernovae. The validity of this resolution rests on the assumption that the RSG mass-loss rates have been seriously underestimated. Meynet et al. (2015) and Georgy et al. (2015) proposed a novel way o ...
Astronomy Astrophysics A VLT/FLAMES survey for massive binaries in Westerlund 1 &
... spectra of W239 to search for the signature of a companion(s), noting that the shorter wavelength data were of too low S/N and resolution to permit such an analysis and the longer wavelength data are dominated by a near-IR excess due to hot dust (Sects. 2.2 and 2.3). The FLAMES spectra cover Pa11-16 ...
... spectra of W239 to search for the signature of a companion(s), noting that the shorter wavelength data were of too low S/N and resolution to permit such an analysis and the longer wavelength data are dominated by a near-IR excess due to hot dust (Sects. 2.2 and 2.3). The FLAMES spectra cover Pa11-16 ...
THE FINAL FATE OF STARS THAT IGNITE NEON AND OXYGEN
... starts to become enriched with 24 Mg and 28 Si. It happens, then, that producing silicon from oxygen in this way is quicker than oxygen–oxygen fusion; however, it must rely upon the oxygenoxygen fusion reactions as the source of α particles. After the neon is processed into 24 Mg, 28 Si, and 16 O by ...
... starts to become enriched with 24 Mg and 28 Si. It happens, then, that producing silicon from oxygen in this way is quicker than oxygen–oxygen fusion; however, it must rely upon the oxygenoxygen fusion reactions as the source of α particles. After the neon is processed into 24 Mg, 28 Si, and 16 O by ...
Test 4 Review
... The quasars we see are very distant, meaning they existed a long time ago. Therefore, they may represent an early stage in galaxy development. The quasars in this image are shown with their host galaxies. ...
... The quasars we see are very distant, meaning they existed a long time ago. Therefore, they may represent an early stage in galaxy development. The quasars in this image are shown with their host galaxies. ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.