New Mass Loss Measurements from Astrospheric Lyα Absorption
... active stars, with the y Boo example being particularly relevant since the stars in this binary are easily the most solar-like of those in this high-activity regime. Thus, the location of y Boo is shown in Figure 3b in order to infer what the solar wind might have been like at times earlier than t p ...
... active stars, with the y Boo example being particularly relevant since the stars in this binary are easily the most solar-like of those in this high-activity regime. Thus, the location of y Boo is shown in Figure 3b in order to infer what the solar wind might have been like at times earlier than t p ...
WORD - Astrophysics
... states of matter in the Universe: neutron stars and black holes. In spite of the undeniable progress made during the last few decades in understanding how stars form and evolve, essential questions remain for which the collecting area and angular resolution of an extremely large optical/infrared tel ...
... states of matter in the Universe: neutron stars and black holes. In spite of the undeniable progress made during the last few decades in understanding how stars form and evolve, essential questions remain for which the collecting area and angular resolution of an extremely large optical/infrared tel ...
The surface composition of Beta Pictoris
... listed in Tab. 1. Figure 1 illustrates the case of Cr II; error limits shown are estimates based on the fit of observed and synthetic spectrum. Ti II and Fe II look similar, but the spread is somewhat larger. We suppose that the Cr II gf -values have the highest internal accuracy. The slight residua ...
... listed in Tab. 1. Figure 1 illustrates the case of Cr II; error limits shown are estimates based on the fit of observed and synthetic spectrum. Ti II and Fe II look similar, but the spread is somewhat larger. We suppose that the Cr II gf -values have the highest internal accuracy. The slight residua ...
Chapter 1-3
... the Master course on Binary Stars. All observed properties mentioned above are surface properties. Therefore we need a theory of stellar structure to derive the internal properties of a star. However, some direct windows on the interior of a star exist: • neutrinos, which escape from the interior wi ...
... the Master course on Binary Stars. All observed properties mentioned above are surface properties. Therefore we need a theory of stellar structure to derive the internal properties of a star. However, some direct windows on the interior of a star exist: • neutrinos, which escape from the interior wi ...
Small galaxies are growing smaller
... decade with the development of multi-object spectroscopy. With the “2 degree Field” (2dF) spectrograph on the Anglo-Australian Telescope, for instance, we can now obtain spectra for 400 objects simultaneously. This has enabled the present generation of huge galaxy redshift surveys, such as 2dFGRS wi ...
... decade with the development of multi-object spectroscopy. With the “2 degree Field” (2dF) spectrograph on the Anglo-Australian Telescope, for instance, we can now obtain spectra for 400 objects simultaneously. This has enabled the present generation of huge galaxy redshift surveys, such as 2dFGRS wi ...
Comprehensive Census and Complete Characterization of Nearby
... can eliminate as many giants as possible since only Hipparcos stars have precise distance measurements, and finally that the stars show a significant amount of excess above the photosphere. The summary of these criteria are included in Table 1 and more thorough description can be found in Cotten & Son ...
... can eliminate as many giants as possible since only Hipparcos stars have precise distance measurements, and finally that the stars show a significant amount of excess above the photosphere. The summary of these criteria are included in Table 1 and more thorough description can be found in Cotten & Son ...
An analogy
... – distances are required to understand both the sizes and ages of the galaxies – distances require redshifts AND cosmological parameters – distant galaxies are younger than those used to define the Hubble Sequence – more peculiar galaxies are observed: could be due to patchy star formation (younger ...
... – distances are required to understand both the sizes and ages of the galaxies – distances require redshifts AND cosmological parameters – distant galaxies are younger than those used to define the Hubble Sequence – more peculiar galaxies are observed: could be due to patchy star formation (younger ...
Determining Distances to Other Galaxies
... If stars in the disk of a spiral galaxy are on slightly eccentric orbits, and the position angle of these ellipses vary with radius, a spiral-shaped density wave can be formed from a set of nested ovals. Density wave theory is really based on the premise that mutual gravitational attraction of stars ...
... If stars in the disk of a spiral galaxy are on slightly eccentric orbits, and the position angle of these ellipses vary with radius, a spiral-shaped density wave can be formed from a set of nested ovals. Density wave theory is really based on the premise that mutual gravitational attraction of stars ...
White dwarf cooling sequences and cosmochronology
... the size of MH well below this critical value, this source can be neglected. Fortunately, when neutrino emission becomes dominant, the different thermal structures converge to a unique one, granting the uniformity of the models with log(L/L ) ≤ −1.5. Furthermore, since the time necessary to reach t ...
... the size of MH well below this critical value, this source can be neglected. Fortunately, when neutrino emission becomes dominant, the different thermal structures converge to a unique one, granting the uniformity of the models with log(L/L ) ≤ −1.5. Furthermore, since the time necessary to reach t ...
Abstracts - Physics of Evolved Stars 2015
... solar masses per year. Evolutionary models suggest that this phase does not last much longer than 10^5 years, implying that these stars are not likely to have lost more than one solar mass before entering the high mass-loss phase. To evolve into a post-AGB star, with a white dwarf cooling at the cen ...
... solar masses per year. Evolutionary models suggest that this phase does not last much longer than 10^5 years, implying that these stars are not likely to have lost more than one solar mass before entering the high mass-loss phase. To evolve into a post-AGB star, with a white dwarf cooling at the cen ...
View the sky`s greatest nebula
... some is due to various hydrogen emission lines, and some comes from shocked molecular hydrogen, which glows at 2 microns. At a distance of just under 1,500 light-years, the Orion Nebula is the closest site of high-mass star formation to the Sun. ...
... some is due to various hydrogen emission lines, and some comes from shocked molecular hydrogen, which glows at 2 microns. At a distance of just under 1,500 light-years, the Orion Nebula is the closest site of high-mass star formation to the Sun. ...
Summer 2014 Mercury - Astronomical Society of the Pacific
... the outline of the animal — the head, eye, neck and back, tail, and so on. Often she’d get only part way, and suddenly I could connect the lines and see the entire animal. The first time this happened, I thought of the constellations. What the guides were doing in the caves is the same thing that we ...
... the outline of the animal — the head, eye, neck and back, tail, and so on. Often she’d get only part way, and suddenly I could connect the lines and see the entire animal. The first time this happened, I thought of the constellations. What the guides were doing in the caves is the same thing that we ...
Thu th surf c
... Thus the surface facing us periodically approaches and recedes from us, thereby causing the spectral lines to shift periodically to the blue and to the red. When we plot a Cepheid's variations in velocity against time we obtain a velocity curve for the star. ...
... Thus the surface facing us periodically approaches and recedes from us, thereby causing the spectral lines to shift periodically to the blue and to the red. When we plot a Cepheid's variations in velocity against time we obtain a velocity curve for the star. ...
3.2 Spectra and Spectral Classification
... (a) absolute magnitude or luminosity and (b) spectral type or effective temperature (sometimes also color index) That means there exist different forms of this diagram, usually ● log L versus spectral type ● log L versus log T ● M versus B-V ...
... (a) absolute magnitude or luminosity and (b) spectral type or effective temperature (sometimes also color index) That means there exist different forms of this diagram, usually ● log L versus spectral type ● log L versus log T ● M versus B-V ...
Zapartas_deMink_Izzard_AA_2017
... Most massive stars, the progenitors of core-collapse supernovae, are in close binary systems and may interact with their companion through mass transfer or merging. We undertake a population synthesis study to compute the delay-time distribution of core-collapse supernovae, that is, the supernova ra ...
... Most massive stars, the progenitors of core-collapse supernovae, are in close binary systems and may interact with their companion through mass transfer or merging. We undertake a population synthesis study to compute the delay-time distribution of core-collapse supernovae, that is, the supernova ra ...
2_ISM - UCT Astronomy Department
... Assume that size a, refraction index m and number density n of particles is known •all particles are spheres with radius a geometrical cross section is π a² the true extinction cross section of particles: ...
... Assume that size a, refraction index m and number density n of particles is known •all particles are spheres with radius a geometrical cross section is π a² the true extinction cross section of particles: ...
Supernovae and Gamma-Ray Bursts (draft)
... The second important explosion mechanism has nothing to do with massive stars, but is generally believed to occur in accreting CO white dwarfs when their mass approaches the Chandrasekhar mass. When the mass reaches ∼ 1.37 M⊙, carbon is ignited in or near the centre of the white dwarf. Initially, th ...
... The second important explosion mechanism has nothing to do with massive stars, but is generally believed to occur in accreting CO white dwarfs when their mass approaches the Chandrasekhar mass. When the mass reaches ∼ 1.37 M⊙, carbon is ignited in or near the centre of the white dwarf. Initially, th ...
Catching Planets in Formation with GMT
... • Substantial mismatch between predicted and observed distribution of exoplanets. • Major uncertainties: • How do gas-giant planets form. • How much do planets migrate. • Are there many habitable (water, etc) planets. ...
... • Substantial mismatch between predicted and observed distribution of exoplanets. • Major uncertainties: • How do gas-giant planets form. • How much do planets migrate. • Are there many habitable (water, etc) planets. ...
Enhanced lithium depletion in Sun-like stars with orbiting planets.
... 451 stars in the HARPS high precision (better than 1 m/s) radial velocity exoplanet survey11 spanning the effective temperature range between 4900 and 6500 K. These are unevolved, slowly rotating non-active stars from a CORALIE catalogue11. These stars have been monitored with high precision spectro ...
... 451 stars in the HARPS high precision (better than 1 m/s) radial velocity exoplanet survey11 spanning the effective temperature range between 4900 and 6500 K. These are unevolved, slowly rotating non-active stars from a CORALIE catalogue11. These stars have been monitored with high precision spectro ...
Lyra
Lyra (/ˈlaɪərə/; Latin for lyre, from Greek λύρα) is a small constellation. It is one of 48 listed by the 2nd century astronomer Ptolemy, and is one of the 88 constellations recognized by the International Astronomical Union. Lyra was often represented on star maps as a vulture or an eagle carrying a lyre, and hence sometimes referred to as Aquila Cadens or Vultur Cadens. Beginning at the north, Lyra is bordered by Draco, Hercules, Vulpecula, and Cygnus. Lyra is visible from the northern hemisphere from spring through autumn, and nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months.The lucida or brightest star—and one of the brightest stars in the sky—is the white main sequence star Vega, a corner of the Summer Triangle. Beta Lyrae is the prototype of a class of stars known as Beta Lyrae variables, binary stars so close to each other that they become egg-shaped and material flows from one to the other. Epsilon Lyrae, known informally as the Double Double, is a complex multiple star system. Lyra also hosts the Ring Nebula, the second-discovered and best-known planetary nebula.