Understanding Variable Stars - Central Florida Astronomical Society
... First observation of radio pulses from a pulsar, CP1919, by Jocelyn Bell and Anthony Hewish 98 Probing the mysterious heart of the Crab Nebula, the tattered remains of an exploding star, astronomers have found this object to be even more dynamic than previously understood 99 The periods of pulsars, ...
... First observation of radio pulses from a pulsar, CP1919, by Jocelyn Bell and Anthony Hewish 98 Probing the mysterious heart of the Crab Nebula, the tattered remains of an exploding star, astronomers have found this object to be even more dynamic than previously understood 99 The periods of pulsars, ...
The evolution of close binaries with white dwarf components
... 6.5M⊙ . M . 8M⊙ , carbon will ignite which leads to an oxygen-neon core. For all lowand intermediate-mass stars, stellar evolution ends when the envelope is dispersed into the interstellar medium by stellar winds. The remaining core continues to contract as it cools down, until it is supported by el ...
... 6.5M⊙ . M . 8M⊙ , carbon will ignite which leads to an oxygen-neon core. For all lowand intermediate-mass stars, stellar evolution ends when the envelope is dispersed into the interstellar medium by stellar winds. The remaining core continues to contract as it cools down, until it is supported by el ...
Particle Physics from Stars
... The discussion in the previous section suggests that the emission of new weakly interacting particles from stars primarily modifies the time scale of evolution. For the Sun this effect is less useful to constrain particle emission than, say, the modified p-mode frequencies or the direct measurement ...
... The discussion in the previous section suggests that the emission of new weakly interacting particles from stars primarily modifies the time scale of evolution. For the Sun this effect is less useful to constrain particle emission than, say, the modified p-mode frequencies or the direct measurement ...
2012 December Vol. 49 No 584
... spectrum. In addition to the narrow lines reported previously, the new spectra also show very broad lines typical of a normal Type II supernova. H Balmer lines have strong P Cygni profiles, with a minimum in the absorption at -6000 km/s, and a blue edge to the absorption at -13,000 km/s. Although ca ...
... spectrum. In addition to the narrow lines reported previously, the new spectra also show very broad lines typical of a normal Type II supernova. H Balmer lines have strong P Cygni profiles, with a minimum in the absorption at -6000 km/s, and a blue edge to the absorption at -13,000 km/s. Although ca ...
An X-Ray, Optical and Infra-red study of High-Mass X
... First and foremost I would like to thank my supervisor, Malcolm Coe, for his continued guidance and support. His drive to obtain and exploit all manner of data has given me a wealth of information on which to base my thesis and sent me to some of the world’s most incredible places in the process. I ...
... First and foremost I would like to thank my supervisor, Malcolm Coe, for his continued guidance and support. His drive to obtain and exploit all manner of data has given me a wealth of information on which to base my thesis and sent me to some of the world’s most incredible places in the process. I ...
Untitled - METU Astrophysics Home Page
... regarding their formation was proposed in the work of Baade and Zwicky in 1934, whom foreseen the likelihood of neutron stars’ birth in supernova explosions. In the following years, Oppenheimer and Volkoff carried out the primary calculations of neutron star mass and radii. However, the first observa ...
... regarding their formation was proposed in the work of Baade and Zwicky in 1934, whom foreseen the likelihood of neutron stars’ birth in supernova explosions. In the following years, Oppenheimer and Volkoff carried out the primary calculations of neutron star mass and radii. However, the first observa ...
Giant star seismology
... through their global intrinsic oscillations – is already more than a century old. An early remarkable result was obtained for Cepheids revealing the period-luminosity relation (Leavitt and Pickering, 1912), which played an important role in measuring distances of galaxies and star clusters and ultim ...
... through their global intrinsic oscillations – is already more than a century old. An early remarkable result was obtained for Cepheids revealing the period-luminosity relation (Leavitt and Pickering, 1912), which played an important role in measuring distances of galaxies and star clusters and ultim ...
The evolution of low-metallicity massive stars - Argelander
... TWUIN stars are fast rotating massive stars that are extremely hot (90 kK), very bright and as compact as Wolf–Rayet stars. However, as opposed to Wolf–Rayet stars, their stellar winds are optically thin. As these hot objects emit intense UV radiation, we show that they can explain the unusually hig ...
... TWUIN stars are fast rotating massive stars that are extremely hot (90 kK), very bright and as compact as Wolf–Rayet stars. However, as opposed to Wolf–Rayet stars, their stellar winds are optically thin. As these hot objects emit intense UV radiation, we show that they can explain the unusually hig ...
Evolution of low mass stars
... The HRD inspired an English astronomer, Sir Arthur Stanley Eddington (18821944), when Russell visited London and presented his diagram at a meeting of the Royal Astronomical Society in 1913 (Eisberg, 2002). At the time, Eddington was the chief assistant of the Royal Greenwich Observatory. In 1926 Ed ...
... The HRD inspired an English astronomer, Sir Arthur Stanley Eddington (18821944), when Russell visited London and presented his diagram at a meeting of the Royal Astronomical Society in 1913 (Eisberg, 2002). At the time, Eddington was the chief assistant of the Royal Greenwich Observatory. In 1926 Ed ...
Mission Possible: Voyage to the Stars
... their mass. All aspects of a star including size, temperature, life history, and luminosity are determined by the original mass of the star. The HertzsprungRussell diagram is a diagram that is used by astronomers to classify stars by properties such as luminosity, spectral type, color, temperature, ...
... their mass. All aspects of a star including size, temperature, life history, and luminosity are determined by the original mass of the star. The HertzsprungRussell diagram is a diagram that is used by astronomers to classify stars by properties such as luminosity, spectral type, color, temperature, ...
Observations and Theory of Dynamical Triggers for Star Formation
... scale models of triggering (Dopita, Mathewson & Ford 1985) similarly followed from an age progression in the Constellation III region of the Large Magellanic Clouds (Westerlund & Mathewson 1966). (This particular age progression is now in doubt; see Braun et al. 1997). Observations of age progressio ...
... scale models of triggering (Dopita, Mathewson & Ford 1985) similarly followed from an age progression in the Constellation III region of the Large Magellanic Clouds (Westerlund & Mathewson 1966). (This particular age progression is now in doubt; see Braun et al. 1997). Observations of age progressio ...
CORE SUBJECT K to 12 Senior High School Core Curriculum
... Naylor, John. Out of the Blue: A 24-hour Skywatcher's Guide. England: Cambridge University Press, 2002. Pasachoff, Jay and Alex Filipenko. The Cosmos: Astronomy in the New Millenium. California: Thomson-Brooks/Cole, 2007. Shipman, James T., Jerry D. Wilson, and Charles A. Higgins. An Introduction to ...
... Naylor, John. Out of the Blue: A 24-hour Skywatcher's Guide. England: Cambridge University Press, 2002. Pasachoff, Jay and Alex Filipenko. The Cosmos: Astronomy in the New Millenium. California: Thomson-Brooks/Cole, 2007. Shipman, James T., Jerry D. Wilson, and Charles A. Higgins. An Introduction to ...
The spectroscopic Hertzsprung
... in the HR and sHR diagram. Both situations can lead to stars that are overluminous, i.e. stars that have a luminosity larger than the luminosity of a single star of comparable mass and evolutionary state. Kippenhahn & Weigert (1990) showed that main sequence stars are expected to obey the relation L ...
... in the HR and sHR diagram. Both situations can lead to stars that are overluminous, i.e. stars that have a luminosity larger than the luminosity of a single star of comparable mass and evolutionary state. Kippenhahn & Weigert (1990) showed that main sequence stars are expected to obey the relation L ...
Towards the understanding of the deepest layers of solar
... of the model that best represents the internal structure of a star are shifted in relation to the observed ones. The empirical formulation that has been suggested in the literature to correct for this shift was considered and its successfulness is discussed. Chapter 4 concerns the study of small con ...
... of the model that best represents the internal structure of a star are shifted in relation to the observed ones. The empirical formulation that has been suggested in the literature to correct for this shift was considered and its successfulness is discussed. Chapter 4 concerns the study of small con ...
Star formation rates and efficiencies in the Galactic Centre
... There could be several possible explanations for the apparent lack of star formation within the Galactic Centre, which can be split into two categories. Either the low star formation rate is a result of observational bias or uncertainty, or is the product of a physical mechanism. The first observati ...
... There could be several possible explanations for the apparent lack of star formation within the Galactic Centre, which can be split into two categories. Either the low star formation rate is a result of observational bias or uncertainty, or is the product of a physical mechanism. The first observati ...
act_science_bellringers
... evolution” and student 2 believes that “Algol B was always less massive than Algol A.” Therefore, student 2 would say NO, due to the fact that Algol A has always been larger than Algol B. Read these answer choices carefully because the answers are backwards of what is in the text. The text says B is ...
... evolution” and student 2 believes that “Algol B was always less massive than Algol A.” Therefore, student 2 would say NO, due to the fact that Algol A has always been larger than Algol B. Read these answer choices carefully because the answers are backwards of what is in the text. The text says B is ...
MPhil Thesis - Final - Suzanne Knight
... valuable insight into the study of exoplanetary composition and atmospheres. The focus of these surveys now extends to the fate of planetary systems once their host stars evolve off the main sequence. An effective method in finding indirect evidence for the presence of planets is to search for remna ...
... valuable insight into the study of exoplanetary composition and atmospheres. The focus of these surveys now extends to the fate of planetary systems once their host stars evolve off the main sequence. An effective method in finding indirect evidence for the presence of planets is to search for remna ...
The chemical history of molecules in circumstellar disks I: Ices
... chemical evolution from the pre-stellar core to the protostar and circumstellar disk. The model computes infall trajectories from any point in the cloud core and tracks the radial and vertical motion of material in the viscously evolving disk. It includes a full time-dependent radiative transfer tre ...
... chemical evolution from the pre-stellar core to the protostar and circumstellar disk. The model computes infall trajectories from any point in the cloud core and tracks the radial and vertical motion of material in the viscously evolving disk. It includes a full time-dependent radiative transfer tre ...
The Role of Radioactive Isotopes in Astrophysics
... nuclei do not obey Hoyle’s equation but instead are proportional to the initial metallicity of each star. Hoyle’s paper also first noted that 22 Ne would be a source of free neutrons; indeed, it is today their major source in burning shells of massive stars, although that insight is usually attribut ...
... nuclei do not obey Hoyle’s equation but instead are proportional to the initial metallicity of each star. Hoyle’s paper also first noted that 22 Ne would be a source of free neutrons; indeed, it is today their major source in burning shells of massive stars, although that insight is usually attribut ...
celestial navigation heaven`s guide for mere
... temperatures of less than 4000K. Red dwarf stars are the most common type of stars. An example of a red dwarf is the star Proxima Centauri. The Sun, on the other hand, is a yellow dwarf star. Meanwhile, the giant and supergiant group consists of red giant stars, blue giants and supergiants. A red gi ...
... temperatures of less than 4000K. Red dwarf stars are the most common type of stars. An example of a red dwarf is the star Proxima Centauri. The Sun, on the other hand, is a yellow dwarf star. Meanwhile, the giant and supergiant group consists of red giant stars, blue giants and supergiants. A red gi ...
2 The Concept of “Spectral Classes”
... “peculiar.” For composite spectra (P1 or P2= 1) the spectral type of the secondary star is specified by P3P4 – that is, this two-digit code gives the TT type of the secondary. If the secondary’s type is not known, it is coded in P3P4 as”00”. In the case of a non-composite spectrum with the peculiari ...
... “peculiar.” For composite spectra (P1 or P2= 1) the spectral type of the secondary star is specified by P3P4 – that is, this two-digit code gives the TT type of the secondary. If the secondary’s type is not known, it is coded in P3P4 as”00”. In the case of a non-composite spectrum with the peculiari ...
Type II supernova
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, and no more than 40–50 times, the mass of the Sun (M☉) for this type of explosion. It is distinguished from other types of supernovae by the presence of hydrogen in its spectrum. Type II supernovae are mainly observed in the spiral arms of galaxies and in H II regions, but not in elliptical galaxies.Stars generate energy by the nuclear fusion of elements. Unlike the Sun, massive stars possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium, albeit at increasingly higher temperatures and pressures, causing increasingly shorter stellar life spans. The degeneracy pressure of electrons and the energy generated by these fusion reactions are sufficient to counter the force of gravity and prevent the star from collapsing, maintaining stellar equilibrium. The star fuses increasingly higher mass elements, starting with hydrogen and then helium, progressing up through the periodic table until a core of iron and nickel is produced. Fusion of iron or nickel produces no net energy output, so no further fusion can take place, leaving the nickel-iron core inert. Due to the lack of energy output allowing outward pressure, equilibrium is broken.When the mass of the inert core exceeds the Chandrasekhar limit of about 1.4 M☉, electron degeneracy alone is no longer sufficient to counter gravity and maintain stellar equilibrium. A cataclysmic implosion takes place within seconds, in which the outer core reaches an inward velocity of up to 23% of the speed of light and the inner core reaches temperatures of up to 100 billion kelvin. Neutrons and neutrinos are formed via reversed beta-decay, releasing about 1046 joules (100 foes) in a ten-second burst. The collapse is halted by neutron degeneracy, causing the implosion to rebound and bounce outward. The energy of this expanding shock wave is sufficient to accelerate the surrounding stellar material to escape velocity, forming a supernova explosion, while the shock wave and extremely high temperature and pressure briefly allow for theproduction of elements heavier than iron. Depending on initial size of the star, the remnants of the core form a neutron star or a black hole. Because of the underlying mechanism, the resulting nova is also described as a core-collapse supernova.There exist several categories of Type II supernova explosions, which are categorized based on the resulting light curve—a graph of luminosity versus time—following the explosion. Type II-L supernovae show a steady (linear) decline of the light curve following the explosion, whereas Type II-P display a period of slower decline (a plateau) in their light curve followed by a normal decay. Type Ib and Ic supernovae are a type of core-collapse supernova for a massive star that has shed its outer envelope of hydrogen and (for Type Ic) helium. As a result, they appear to be lacking in these elements.