Spectral modeling of nebular-phase supernovae Anders Jerkstrand Department of Astronomy
... to analyze them. The specific aims of this thesis have been to develop state-of-the-art computational models for nebular-phase SNe, and apply these models to derive properties of hydrogen-rich core-collapse SNe. We initially investigate the very late phases of the famous SN 1987A, which has mainly b ...
... to analyze them. The specific aims of this thesis have been to develop state-of-the-art computational models for nebular-phase SNe, and apply these models to derive properties of hydrogen-rich core-collapse SNe. We initially investigate the very late phases of the famous SN 1987A, which has mainly b ...
Mergers of massive main sequence binaries
... In this bachelor research project, we investigated mergers between close main-sequence binaries with the aim of determining whether they result in blue stragglers. We define blue stragglers to be hot and luminous stars that cannot be explained with canonical single star evolution models2 . Using a p ...
... In this bachelor research project, we investigated mergers between close main-sequence binaries with the aim of determining whether they result in blue stragglers. We define blue stragglers to be hot and luminous stars that cannot be explained with canonical single star evolution models2 . Using a p ...
pasta Jos´e A. Pons , Daniele Vigan`o and Nanda Rea
... It has long been hoped that stringent constraints could be placed on the equation of state of dense matter from astrophysical measurements of neutron stars, the compact remnants of the explosion of massive stars. Up to the present time, however, despite important breakthrough discoveries [1, 2, 3] ...
... It has long been hoped that stringent constraints could be placed on the equation of state of dense matter from astrophysical measurements of neutron stars, the compact remnants of the explosion of massive stars. Up to the present time, however, despite important breakthrough discoveries [1, 2, 3] ...
Variable Star Spectroscopy 2008
... (Wavelengths in the Infra Red beyond about 7000A are invisible to the eye but are detectable by CCD cameras (provided they are not filtered out as they are in most ...
... (Wavelengths in the Infra Red beyond about 7000A are invisible to the eye but are detectable by CCD cameras (provided they are not filtered out as they are in most ...
Preliminary results of the Be stars proportion in LMC open
... •Be stars are non supergiant B-type that show or have shown emission line mainly in Hα. The Be phenomenon is transient. Be stars are fast rotators, reaching ~80% of their angular critical velocity. The fast rotation is a major factor in the matter ejection leading to the circumstellar disk and the e ...
... •Be stars are non supergiant B-type that show or have shown emission line mainly in Hα. The Be phenomenon is transient. Be stars are fast rotators, reaching ~80% of their angular critical velocity. The fast rotation is a major factor in the matter ejection leading to the circumstellar disk and the e ...
the paper - Universitäts
... of He 2-131 (middle), since its mass loss rate is obviously too small, as evidenced by the presence of almost only purely photospheric lines hardly influenced by the thin wind – indicating that this CSPN must have a much larger luminosity, because L is the major factor determining the mass loss rate ...
... of He 2-131 (middle), since its mass loss rate is obviously too small, as evidenced by the presence of almost only purely photospheric lines hardly influenced by the thin wind – indicating that this CSPN must have a much larger luminosity, because L is the major factor determining the mass loss rate ...
Lecture 2. Isolated Neutron Stars – I.
... Accretion in close binaries Accretion is the most powerful source of energy realized in Nature, which can give a huge energy output. When matter fall down onto the surface of a neutron star up to 10% of mc2 can be released. ...
... Accretion in close binaries Accretion is the most powerful source of energy realized in Nature, which can give a huge energy output. When matter fall down onto the surface of a neutron star up to 10% of mc2 can be released. ...
The Star-Galaxy Era of Big History in the Light of Universal
... At present, it is widely accepted that the stars were first to emerge, but those were the giant stars, much more massive than most of the later-formed ones (May et al. 2008). Because of the absence of carbon, oxygen and other elements that absorb the energy from ...
... At present, it is widely accepted that the stars were first to emerge, but those were the giant stars, much more massive than most of the later-formed ones (May et al. 2008). Because of the absence of carbon, oxygen and other elements that absorb the energy from ...
PPT
... suddenly become a black hole, it’s gravitational field would look exactly the same! The planets will keep moving around as if nothing happened! • Black holes emit no light, because light cannot escape. Thus, black holes are dark and invisible. It is true, light cannot escape from the event horizon ( ...
... suddenly become a black hole, it’s gravitational field would look exactly the same! The planets will keep moving around as if nothing happened! • Black holes emit no light, because light cannot escape. Thus, black holes are dark and invisible. It is true, light cannot escape from the event horizon ( ...
A Question of Planets - Vanderbilt University
... that their brightness varies dramatically. More recently astronomers have been studying them because they can provide important insights into how the Sun and solar system evolved. Twenty years ago, scientists thought that T Tauri stars had extremely strong solar winds blowing outward at velocities o ...
... that their brightness varies dramatically. More recently astronomers have been studying them because they can provide important insights into how the Sun and solar system evolved. Twenty years ago, scientists thought that T Tauri stars had extremely strong solar winds blowing outward at velocities o ...
KINEMATIC DISCOVERY OF A STELLAR STREAM LOCATED IN
... (i.e., red points in the top panels of Figure 3) are mostly clustered around [(g − r)0 , g0 ] = [0.55, 18.8] in the on-stream field (top left panel of Figure 3), while the more metal-rich stars (light blue points) scatter throughout the diagram. We suggest that these stars are part of the RGB of a s ...
... (i.e., red points in the top panels of Figure 3) are mostly clustered around [(g − r)0 , g0 ] = [0.55, 18.8] in the on-stream field (top left panel of Figure 3), while the more metal-rich stars (light blue points) scatter throughout the diagram. We suggest that these stars are part of the RGB of a s ...
Heic0116: EMBARGOED UNTIL: 20:00 (CET) WEDNESDAY 05
... objects for Dark Matter. One of many possibilities is that the Dark Matter consists of weakly interacting, massive sub-atomic sized particles known as WIMPs. Alternatively Dark Matter may consist of massive compact objects (MACHOs), such as dead or dying stars (neutron stars and cool dwarf stars), b ...
... objects for Dark Matter. One of many possibilities is that the Dark Matter consists of weakly interacting, massive sub-atomic sized particles known as WIMPs. Alternatively Dark Matter may consist of massive compact objects (MACHOs), such as dead or dying stars (neutron stars and cool dwarf stars), b ...
Contents
... System, the inverse square law works very well. In one such model, by Milgrom, the modification takes effect at gravitational accelerations of less than 10-9 m s-2 [i.e. ~10-10 g] and for these accelerations the gravitational force falls of as inverse r rather than inverse r2]. This is a classic exa ...
... System, the inverse square law works very well. In one such model, by Milgrom, the modification takes effect at gravitational accelerations of less than 10-9 m s-2 [i.e. ~10-10 g] and for these accelerations the gravitational force falls of as inverse r rather than inverse r2]. This is a classic exa ...
Targets for Small Telescopes
... the local group of Galaxies. The entire nebula spans 3,000 ly, which compares to the Orion Nebula spanning 40 ly. The Star Cluster at the Centre of the Nebula (also NGC 2070), spans 250 light years. If the nebula were contained within our own Galaxy it would fill the entire constellation of Orion (3 ...
... the local group of Galaxies. The entire nebula spans 3,000 ly, which compares to the Orion Nebula spanning 40 ly. The Star Cluster at the Centre of the Nebula (also NGC 2070), spans 250 light years. If the nebula were contained within our own Galaxy it would fill the entire constellation of Orion (3 ...
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.