Photometry Review from Some Constellations of Autumn in the
... Orion Nebula. The dark lane that extends from the north toward the bright region is called the "Fish's Mouth". The illuminated regions to both sides are called the "Wings". Other features include "The Sword", "The Thrust", and "The Sail". Ring Nebula The Ring Nebula (also catalogued as Messier 57, M ...
... Orion Nebula. The dark lane that extends from the north toward the bright region is called the "Fish's Mouth". The illuminated regions to both sides are called the "Wings". Other features include "The Sword", "The Thrust", and "The Sail". Ring Nebula The Ring Nebula (also catalogued as Messier 57, M ...
Theoretical and observational framework Spectroscopic approach
... Fabbian, Recio-Blanco et al. 2003, in preparation • Radiative levitation of metals and helium depletion is detected for HB stars hotter than ~11 000 K in NGC 1904 for the first time. Fe, Ti, Cr and other metal species are enhanced to supersolar values. He abundance below the solar value. • Slightly ...
... Fabbian, Recio-Blanco et al. 2003, in preparation • Radiative levitation of metals and helium depletion is detected for HB stars hotter than ~11 000 K in NGC 1904 for the first time. Fe, Ti, Cr and other metal species are enhanced to supersolar values. He abundance below the solar value. • Slightly ...
Chapter 12: Surveying the Stars 12.1 Properties of Stars How do we
... those that have finished fusing H to He in their cores are no longer on the main sequence. • All stars become larger and redder after exhausting their core hydrogen: giants and ...
... those that have finished fusing H to He in their cores are no longer on the main sequence. • All stars become larger and redder after exhausting their core hydrogen: giants and ...
![An improved classification of B[e]-type stars](http://s1.studyres.com/store/data/015293756_1-5784ffaa4d7d33ad2633e3151daf904c-300x300.png)
An improved classification of B[e]-type stars
... A fraction of the stars that show the B[e] phenomenon are clearly very young stars because they appear in star forming regions. These stars may appear as pre-main sequence stars and show, therefore, many characteristics of and are related to the Herbig Ae/Be stars, also called “HAeBe-stars” (Thé et ...
... A fraction of the stars that show the B[e] phenomenon are clearly very young stars because they appear in star forming regions. These stars may appear as pre-main sequence stars and show, therefore, many characteristics of and are related to the Herbig Ae/Be stars, also called “HAeBe-stars” (Thé et ...
THE PERIOD OF ROTATION OF THE SUN
... As a star ages, it begins to run out of hydrogen in its core, and begins to fuse hydrogen in an expanding shell around the core, like a forest-fire burning outward from its original source. The aging star expands and cools, becoming a red giant. In a cluster, the first stars to do this are the highe ...
... As a star ages, it begins to run out of hydrogen in its core, and begins to fuse hydrogen in an expanding shell around the core, like a forest-fire burning outward from its original source. The aging star expands and cools, becoming a red giant. In a cluster, the first stars to do this are the highe ...
Planetary Nebula
... Credit: Bruce Balick (U. Washington) et al., HST, NASA • After a star like the Sun completes fusion in its core, it throws off its outer layers in a brief, beautiful cosmic display called a planetary nebula. NGC 3242 is such a planetary nebula, with the stellar remnant white dwarf star visible at th ...
... Credit: Bruce Balick (U. Washington) et al., HST, NASA • After a star like the Sun completes fusion in its core, it throws off its outer layers in a brief, beautiful cosmic display called a planetary nebula. NGC 3242 is such a planetary nebula, with the stellar remnant white dwarf star visible at th ...
arXiv:astro-ph/9701131v1 18 Jan 1997
... A star with a slightly larger mass, M∗ = 0.23 M⊙ , experiences the onset of a radiative core when the hydrogen mass fraction dips below 50%. The composition gradients which ensue are sufficient to briefly drive the star to lower effective temperature as the luminosity increases. In this sense, stars ...
... A star with a slightly larger mass, M∗ = 0.23 M⊙ , experiences the onset of a radiative core when the hydrogen mass fraction dips below 50%. The composition gradients which ensue are sufficient to briefly drive the star to lower effective temperature as the luminosity increases. In this sense, stars ...
Cooling neutron stars: Theory and observations
... • Constraints on slow and fast neutrino emission levels • Mass ordering ...
... • Constraints on slow and fast neutrino emission levels • Mass ordering ...
Script Chapter 2, part 1
... 51 Peg b: The historical detection measurements for 51 Peg b, the first extra-solar planets around a normal star, from Mayor and Queloz. The orbital period is about 4.2 days and the RV-semi-amplitude 59 m/s. The scatter of the data points with respect to the fit is 13 m/s. The measurements which wer ...
... 51 Peg b: The historical detection measurements for 51 Peg b, the first extra-solar planets around a normal star, from Mayor and Queloz. The orbital period is about 4.2 days and the RV-semi-amplitude 59 m/s. The scatter of the data points with respect to the fit is 13 m/s. The measurements which wer ...
An Overview of the Gaia
... Smith et al. (2004); image courtesy NASA/JPL – Caltech/STScI LMU, October 8, 2007 ...
... Smith et al. (2004); image courtesy NASA/JPL – Caltech/STScI LMU, October 8, 2007 ...
Driving downsizing with galaxy groups
... orbit, mass ratio etc., but the time delay of at least 1-2 Gyr is fairly ...
... orbit, mass ratio etc., but the time delay of at least 1-2 Gyr is fairly ...
STELLAR STRUCTURE AND EVOLUTION
... evolution by F. Verbunt). The goal of this course on stellar evolution can be formulated as follows: to understand the structure and evolution of stars, and their observational properties, using known laws of physics This involves applying and combining ‘familiar’ physics from many different areas ( ...
... evolution by F. Verbunt). The goal of this course on stellar evolution can be formulated as follows: to understand the structure and evolution of stars, and their observational properties, using known laws of physics This involves applying and combining ‘familiar’ physics from many different areas ( ...
radial metallicity gradients and age-metallicity relation of stars in the
... solar neighbourhood. The survey selection box was defined using the 2MASS photometry: 12 < J < 14 and 0.23 < J − K < 0.45 +0.5E(B−V); if there were not enough targets, the red edge was extended2. With these criteria, we are predominantly selecting FG stars with magnitudes down to V = 16.5 (Gilmore e ...
... solar neighbourhood. The survey selection box was defined using the 2MASS photometry: 12 < J < 14 and 0.23 < J − K < 0.45 +0.5E(B−V); if there were not enough targets, the red edge was extended2. With these criteria, we are predominantly selecting FG stars with magnitudes down to V = 16.5 (Gilmore e ...
“End-of-the-Line” W UMa Eclipsing Binary V523
... of any contact binaries, but they are less evolved. The have had insufficient time to consume significant amounts of their nuclear fuel as contrasted with some of their slower-orbiting, more massive (bluer) and rapidly evolving cousins whose periods, as can be see from Fig. 2, are more spread out. ...
... of any contact binaries, but they are less evolved. The have had insufficient time to consume significant amounts of their nuclear fuel as contrasted with some of their slower-orbiting, more massive (bluer) and rapidly evolving cousins whose periods, as can be see from Fig. 2, are more spread out. ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.