Stellar dust production and composition in the Magellanic Clouds F. Kemper
... MIPS 24 µm found that the overall dust injection to the interstellar medium of the LMC is 2.74 × 10−5 M yr−1 . The dust production is dominated by the category of extreme AGB stars, which are responsible for a dust production rate of 2.36 × 10−5 M yr−1 , against 0.14 and 0.24 × 10−5 M yr−1 for ox ...
... MIPS 24 µm found that the overall dust injection to the interstellar medium of the LMC is 2.74 × 10−5 M yr−1 . The dust production is dominated by the category of extreme AGB stars, which are responsible for a dust production rate of 2.36 × 10−5 M yr−1 , against 0.14 and 0.24 × 10−5 M yr−1 for ox ...
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 ...
Testing
... • Dying stars expel gas and new elements, producing hot bubbles (~106 K). • Hot gas cools, allowing atomic hydrogen clouds to form (~100–10,000 K). • Further cooling permits molecules to form, making molecular clouds (~30 K). • Gravity forms new stars (and planets) in molecular clouds. ...
... • Dying stars expel gas and new elements, producing hot bubbles (~106 K). • Hot gas cools, allowing atomic hydrogen clouds to form (~100–10,000 K). • Further cooling permits molecules to form, making molecular clouds (~30 K). • Gravity forms new stars (and planets) in molecular clouds. ...
Finnish Centre for Astronomy with ESO
... The year 2014 marked the 5th year of operation for FINCA, administratively a Special Unit of the University of Turku, and funded by the Ministry of Education and Culture, and by the participating universities (Aalto, Helsinki, Oulu and Turku). The highest decision-making body is the Board, chaired b ...
... The year 2014 marked the 5th year of operation for FINCA, administratively a Special Unit of the University of Turku, and funded by the Ministry of Education and Culture, and by the participating universities (Aalto, Helsinki, Oulu and Turku). The highest decision-making body is the Board, chaired b ...
Turbulent Flow-Driven Molecular Cloud Formation: A Solution to the
... yet the ages of the stars produced by these clouds provide uniquely detailed constraints on cloud ages that are not obtainable in any other way (e.g., Hartmann et al. 1991; Feigelson 1996). Because of the importance of the stellar population ages, it is worth reviewing the situation in some detail, ...
... yet the ages of the stars produced by these clouds provide uniquely detailed constraints on cloud ages that are not obtainable in any other way (e.g., Hartmann et al. 1991; Feigelson 1996). Because of the importance of the stellar population ages, it is worth reviewing the situation in some detail, ...
Galaxies and the Distance Ladder
... C. The galaxies in clusters move faster than expected on the basis of the luminous matter. D. It explains some of the gravitational lensing that is observed at long distances. ...
... C. The galaxies in clusters move faster than expected on the basis of the luminous matter. D. It explains some of the gravitational lensing that is observed at long distances. ...
THE PERIOD OF ROTATION OF THE SUN
... We had to make several simplifications in the models for this activity. The models do not include the emission from the element argon, which is present in the Cas A spectrum, because the models published by Hwang & Laming do not include it. We also simplified the gas physics to create the models; we ...
... We had to make several simplifications in the models for this activity. The models do not include the emission from the element argon, which is present in the Cas A spectrum, because the models published by Hwang & Laming do not include it. We also simplified the gas physics to create the models; we ...
WFIRSTSurveyScience
... Studies of low mass populations (encompassing stars, brown dwarfs, and even free-floating planetary mass objects) are hindered in star forming regions due to observational and astrophysical effects. These include: the large angular sizes of the nearby molecular clouds harboring newborn and young ste ...
... Studies of low mass populations (encompassing stars, brown dwarfs, and even free-floating planetary mass objects) are hindered in star forming regions due to observational and astrophysical effects. These include: the large angular sizes of the nearby molecular clouds harboring newborn and young ste ...
Circumstellar grains: radiation pressure and
... The interaction of circumstellar grains with a stellar radiation field determines both the radiation pressure force and the equilibrium temperature of the grains. This force, if it exceeds the gravitational attraction, results in the expulsion of the grains, a possible driving mechanism for stellar ...
... The interaction of circumstellar grains with a stellar radiation field determines both the radiation pressure force and the equilibrium temperature of the grains. This force, if it exceeds the gravitational attraction, results in the expulsion of the grains, a possible driving mechanism for stellar ...
Word doc - UC-HiPACC - University of California, Santa Cruz
... in which it appears from Earth—is in a polar orbit around the Milky Way and in the process of merging with our galaxy. In 2003, infrared telescopes and supercomputers that traced the orbital motions of its stars revealed that the Sagittarius Dwarf had actually collided with the Milky Way twice—once ...
... in which it appears from Earth—is in a polar orbit around the Milky Way and in the process of merging with our galaxy. In 2003, infrared telescopes and supercomputers that traced the orbital motions of its stars revealed that the Sagittarius Dwarf had actually collided with the Milky Way twice—once ...
Star formation and the interstellar medium in galaxy
... A stellar cluster is formed as soon as the region is unstable longer than the collapse time. In this way we have constructed a selfconsistent model where heating and cooling are intimately coupled and direct feedback from star formation is insured. The one major deficiency is that we do not solve th ...
... A stellar cluster is formed as soon as the region is unstable longer than the collapse time. In this way we have constructed a selfconsistent model where heating and cooling are intimately coupled and direct feedback from star formation is insured. The one major deficiency is that we do not solve th ...
PDF only - at www.arxiv.org.
... nearer their host stars; as a consequence, they are more frequently engulfed by the stars during the migration process or stripped of their gaseous envelops. The depleted number of gas giant planets around metal poor stars would then be the result of the synergy between low formation probability, as ...
... nearer their host stars; as a consequence, they are more frequently engulfed by the stars during the migration process or stripped of their gaseous envelops. The depleted number of gas giant planets around metal poor stars would then be the result of the synergy between low formation probability, as ...
The San Diego Astronomy Association`s Annual Banquet
... where the Earth lives. This research also has implications for the search for extraterrestrial life, and especially intelligent life — up until now, scientists have worried that if a solar system didn’t have something like a Jupiter, it might be too dangerous for life to get very far before getting ...
... where the Earth lives. This research also has implications for the search for extraterrestrial life, and especially intelligent life — up until now, scientists have worried that if a solar system didn’t have something like a Jupiter, it might be too dangerous for life to get very far before getting ...
arXiv:astro-ph/0701792v1 29 Jan 2007
... sphere itself and the background dark matter, the sphere will inevitably collapse. So such instability is mainly affected by the ”external” fluctuations. In another words, the equilibrious sphere will always keep in equilibrium unless there is additional mass from the outside added into the system. ...
... sphere itself and the background dark matter, the sphere will inevitably collapse. So such instability is mainly affected by the ”external” fluctuations. In another words, the equilibrious sphere will always keep in equilibrium unless there is additional mass from the outside added into the system. ...
The spectral energy distribution of protoplanetary
... making them relatively rare. Additionally, the discs themselves have a very short dispersal time-scale and thus MYSO–disc systems are likely very rare. However, very recent studies by Preibisch et al. (2011) and Grellmann et al. (2011) suggest the discovery of the potential first discs around high-m ...
... making them relatively rare. Additionally, the discs themselves have a very short dispersal time-scale and thus MYSO–disc systems are likely very rare. However, very recent studies by Preibisch et al. (2011) and Grellmann et al. (2011) suggest the discovery of the potential first discs around high-m ...
Discovery probability of transiting extragalactic planets and
... is the only planet with life in the endless universe, in principal he believes, that from one field full of seeds will grow only one of them”. Simplicius of Cilicia cited that the philosopher Anaxagoras (500 B.C) argued that there are infinity number of worlds in the universe. In the following years ...
... is the only planet with life in the endless universe, in principal he believes, that from one field full of seeds will grow only one of them”. Simplicius of Cilicia cited that the philosopher Anaxagoras (500 B.C) argued that there are infinity number of worlds in the universe. In the following years ...
Polaris
... And Polaris will continue its reign as the North Star for many centuries to come. It will align most closely with the north celestial pole – the point in the sky directly above Earth’s north rotational axis – on March 24, 2100. The computational wizard Jean Meeus figures Polaris will be 27’09” (0.45 ...
... And Polaris will continue its reign as the North Star for many centuries to come. It will align most closely with the north celestial pole – the point in the sky directly above Earth’s north rotational axis – on March 24, 2100. The computational wizard Jean Meeus figures Polaris will be 27’09” (0.45 ...
Spectroscopy: Unlocking the Secrets of Star Light
... An electron orbits a nucleus in a stable energy level. If a photon of a specific frequency interacts with the electron, it can gain sufficient energy to "jump up" one or more levels. The photon is absorbed by the electron so cannot continue on to be detected by an observer. The electron then "de-exc ...
... An electron orbits a nucleus in a stable energy level. If a photon of a specific frequency interacts with the electron, it can gain sufficient energy to "jump up" one or more levels. The photon is absorbed by the electron so cannot continue on to be detected by an observer. The electron then "de-exc ...
Spectroscopy: Unlocking the Secrets of Star Light
... An electron orbits a nucleus in a stable energy level. If a photon of a specific frequency interacts with the electron, it can gain sufficient energy to "jump up" one or more levels. The photon is absorbed by the electron so cannot continue on to be detected by an observer. The electron then "de-exc ...
... An electron orbits a nucleus in a stable energy level. If a photon of a specific frequency interacts with the electron, it can gain sufficient energy to "jump up" one or more levels. The photon is absorbed by the electron so cannot continue on to be detected by an observer. The electron then "de-exc ...
feps_jan_2007_aas - The Formation & Evolution of Planetary
... models of Gorti and Hollenbach (2004) and following Hollenbach et al. (2005) we placed upper limits to the gas surface density for 15 FEPS targets with optically-thin (or lacking) dust disk signatures. The ages of the targets ranged from 3-300 Myr. Our results suggest that there is not enough gas in ...
... models of Gorti and Hollenbach (2004) and following Hollenbach et al. (2005) we placed upper limits to the gas surface density for 15 FEPS targets with optically-thin (or lacking) dust disk signatures. The ages of the targets ranged from 3-300 Myr. Our results suggest that there is not enough gas in ...
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.