Testing
... A. Blown out of galaxy B. Still recycling just like now C. Locked into white dwarfs and low-mass stars ...
... A. Blown out of galaxy B. Still recycling just like now C. Locked into white dwarfs and low-mass stars ...
The Origin, Structure, and Evolution of the Stars
... believe that some of the small dark globules found throughout the bright nebulous regions (as can be seen in Figure 3) are the initial phases of star formation. As the protostar continues to contract, one-half of the potential energy stored up in the gravitational field is converted to heat and incr ...
... believe that some of the small dark globules found throughout the bright nebulous regions (as can be seen in Figure 3) are the initial phases of star formation. As the protostar continues to contract, one-half of the potential energy stored up in the gravitational field is converted to heat and incr ...
Age-Dating of Young Stars and Stellar Systems
... is very different from, e.g., a globular cluster isochrone where most of the luminosity comes from a small mass interval close to the turn-off mass. In a typical massive-star population of single age, stars with vastly different zero-age-mainsequence masses can have similar Teff and L and contribute ...
... is very different from, e.g., a globular cluster isochrone where most of the luminosity comes from a small mass interval close to the turn-off mass. In a typical massive-star population of single age, stars with vastly different zero-age-mainsequence masses can have similar Teff and L and contribute ...
7.4 Evolution on the Main-Sequence Main-sequence (m
... phase. For the Sun, the contraction time to the m-s τK−H ∼ 30 × 106 yr and τm−s ∼ 1010 yr. For a 9 M star, the corresponding times are much shorter with τK−H ∼ 105 yr and τm−s ∼ 20 × 106 yr. As shown in Sect. 7.3, the m-s can be split into two parts depending on the energy generation process for H- ...
... phase. For the Sun, the contraction time to the m-s τK−H ∼ 30 × 106 yr and τm−s ∼ 1010 yr. For a 9 M star, the corresponding times are much shorter with τK−H ∼ 105 yr and τm−s ∼ 20 × 106 yr. As shown in Sect. 7.3, the m-s can be split into two parts depending on the energy generation process for H- ...
Celestial Distances - Wayne State University
... Variables are rare and, therefore, cannot always be found near a star of interest If variables are not available, the H-R diagram may come to the rescue A detailed examination of a star’s spectrum can reveal its spectral class (O, B, etc.) its pressure and hence size (bigger stars have lower pressur ...
... Variables are rare and, therefore, cannot always be found near a star of interest If variables are not available, the H-R diagram may come to the rescue A detailed examination of a star’s spectrum can reveal its spectral class (O, B, etc.) its pressure and hence size (bigger stars have lower pressur ...
Module code: AA1
... 3 stars (Sirius A, Alpha Centauri A and Procyon) appear on both lists. They are very close to the earth and for that reason their below average luminosity is sufficient to make them appear on the list of the 20 brightest stars. The sample group of the nearest stars is more representative than the gr ...
... 3 stars (Sirius A, Alpha Centauri A and Procyon) appear on both lists. They are very close to the earth and for that reason their below average luminosity is sufficient to make them appear on the list of the 20 brightest stars. The sample group of the nearest stars is more representative than the gr ...
star - TeacherWeb
... Steady State Theory. This theory stated that the universe was always the same. Astronomers believe that the expanding universe is the result of an enormous explosion known as the big bang. The explosion occurred 15-20 billion years ago. As the matter moved away from the explosion, gravity caused clu ...
... Steady State Theory. This theory stated that the universe was always the same. Astronomers believe that the expanding universe is the result of an enormous explosion known as the big bang. The explosion occurred 15-20 billion years ago. As the matter moved away from the explosion, gravity caused clu ...
plagiarism - things to know - Science Department
... Stars, rocks and people all emit light, and and people included. The temperature of which wavelength of light will be most the star, rock or person determines which strongly radiated depends on the wavelength of light will be most strongly temperature of the star, rock or person. For radiated. In th ...
... Stars, rocks and people all emit light, and and people included. The temperature of which wavelength of light will be most the star, rock or person determines which strongly radiated depends on the wavelength of light will be most strongly temperature of the star, rock or person. For radiated. In th ...
Powerpoint
... •Temperature along the horizontal axis (measured in Kelvin) The stars Vega and Sirius are brighter than the Sun, and also hotter. Where would you put them? Where would you mark the Sun on the plot? ...
... •Temperature along the horizontal axis (measured in Kelvin) The stars Vega and Sirius are brighter than the Sun, and also hotter. Where would you put them? Where would you mark the Sun on the plot? ...
Star in a Box - Las Cumbres Observatory Global Telescope
... •Temperature along the horizontal axis (measured in Kelvin) The stars Vega and Sirius are brighter than the Sun, and also hotter. Where would you put them? Where would you mark the Sun on the plot? ...
... •Temperature along the horizontal axis (measured in Kelvin) The stars Vega and Sirius are brighter than the Sun, and also hotter. Where would you put them? Where would you mark the Sun on the plot? ...
mslien~1
... Out of deep images & with the detection 20 of stars on 5 level Succeeded to detected very faint (low mass) stars ...
... Out of deep images & with the detection 20 of stars on 5 level Succeeded to detected very faint (low mass) stars ...
Star - Astrophysics
... These are moderate mass stars (e.g. Sirius’ companion Sirius B with M = 1.05M), but with very high temperatures ( ~30000 K) and very low luminosities (~3 x 10−3L) – hence their position in the H-R diagram. These values imply radii ~7 x 10−3R ~5000km and therefore a density 3 x 109kg m−3. They are ...
... These are moderate mass stars (e.g. Sirius’ companion Sirius B with M = 1.05M), but with very high temperatures ( ~30000 K) and very low luminosities (~3 x 10−3L) – hence their position in the H-R diagram. These values imply radii ~7 x 10−3R ~5000km and therefore a density 3 x 109kg m−3. They are ...
Final Review Sheet
... For stars below 0.5 Msun, the hydrogen shell adds to the helium core until the hydrogen is gone. The core experiences the same problem a 0.08 Msun star did igniting H. It can't ignite He. Ends its life (sometime in the distant future) as a helium white dwarf. Never ignites helium burning. For stars ...
... For stars below 0.5 Msun, the hydrogen shell adds to the helium core until the hydrogen is gone. The core experiences the same problem a 0.08 Msun star did igniting H. It can't ignite He. Ends its life (sometime in the distant future) as a helium white dwarf. Never ignites helium burning. For stars ...
Evolution of High
... high mass of the star. In an instant, electrons are force to combine with the protons in the iron nuclei to form neutrons, releasing neutrinos in the process. • The collapse of the iron core can be stopped by the neutron degenerate pressure of the newly formed neutron core, if the star is not too he ...
... high mass of the star. In an instant, electrons are force to combine with the protons in the iron nuclei to form neutrons, releasing neutrinos in the process. • The collapse of the iron core can be stopped by the neutron degenerate pressure of the newly formed neutron core, if the star is not too he ...
Core-collapse supernovae and their massive progenitors
... Mg, triggering a supernova. Poelarends et al. (2006) indicate up to 10% of core-collapse SNe are due to SAGB stars at solar metallicity, with a higher fraction in metal-poor environments. Type II-P SNe (“P” stands for the plateau phase in their lightcurve) are by far the most common type of core-col ...
... Mg, triggering a supernova. Poelarends et al. (2006) indicate up to 10% of core-collapse SNe are due to SAGB stars at solar metallicity, with a higher fraction in metal-poor environments. Type II-P SNe (“P” stands for the plateau phase in their lightcurve) are by far the most common type of core-col ...
Lecture 8a Star Formation 10/15/2014
... • If we use well-understood close stars to determine the overall brightness scale of a specific class of star, then measuring the spectrum can be used to give the distance for stars > 500 LY away 1. Determine Surface Temperature + spectral class of star 2. Determine where on HR diagram should go 3. ...
... • If we use well-understood close stars to determine the overall brightness scale of a specific class of star, then measuring the spectrum can be used to give the distance for stars > 500 LY away 1. Determine Surface Temperature + spectral class of star 2. Determine where on HR diagram should go 3. ...
H-R Diagram
... White dwarfs are small, hot stars that are near the end of their lives. They are the leftover cores of giants and supergiants. 7. Classify: Proxima Centauri is the nearest star to the Sun. It has a luminosity of 0.0017 and a temperature of 3,000 K. A. Which star group does Proxima Centauri belong to ...
... White dwarfs are small, hot stars that are near the end of their lives. They are the leftover cores of giants and supergiants. 7. Classify: Proxima Centauri is the nearest star to the Sun. It has a luminosity of 0.0017 and a temperature of 3,000 K. A. Which star group does Proxima Centauri belong to ...
Post main sequence evolution
... Key points: -All stars in the cluster have the same age (were born at the same time) -Massive stars run out of fuel (leave the main sequence) sooner than less massive stars. The position of the “turn off point” is what tells us the age of a cluster. This is due to the fact that mass is related to th ...
... Key points: -All stars in the cluster have the same age (were born at the same time) -Massive stars run out of fuel (leave the main sequence) sooner than less massive stars. The position of the “turn off point” is what tells us the age of a cluster. This is due to the fact that mass is related to th ...
determining stellar parameters from star`s
... reaching us from deeper layers is seen as coming from the photosphere; hence its name. The photospherical gas is relatively cool; therefore, it absorbs part of the light coming from lower layers, giving rise to an absorption and emission line spectrum. The dominant feature in most stars’ spectra is ...
... reaching us from deeper layers is seen as coming from the photosphere; hence its name. The photospherical gas is relatively cool; therefore, it absorbs part of the light coming from lower layers, giving rise to an absorption and emission line spectrum. The dominant feature in most stars’ spectra is ...
Chapter 11
... a. About 40 weeks. b. About 30,000 years. c. About 30 million years. d. About 1 billion years. e. About 5 billion years. ...
... a. About 40 weeks. b. About 30,000 years. c. About 30 million years. d. About 1 billion years. e. About 5 billion years. ...
6.1 Introduction
... metallicities of only 10−4 to 10−5 of solar metallicity or, in the shorthand commonly used by astronomers, with [Fe/H] = −4 to −5. Thus, [Fe/H]star = log (Fe/H)star − log (Fe/H) . The relative proportions of different elements of the periodic table in the atmospheres of these stars can be very diff ...
... metallicities of only 10−4 to 10−5 of solar metallicity or, in the shorthand commonly used by astronomers, with [Fe/H] = −4 to −5. Thus, [Fe/H]star = log (Fe/H)star − log (Fe/H) . The relative proportions of different elements of the periodic table in the atmospheres of these stars can be very diff ...
Altair - the hottest `cool` star in X-rays
... 2.4 MK and its emission measure distribution (EMD) is dominated by rather cool plasma at temperatures in the range of 1 – 4 MK, additionally a weak hotter component seems to contribute at a few percent level. These properties are quite typical for weakly active stars and similar to those of the quie ...
... 2.4 MK and its emission measure distribution (EMD) is dominated by rather cool plasma at temperatures in the range of 1 – 4 MK, additionally a weak hotter component seems to contribute at a few percent level. These properties are quite typical for weakly active stars and similar to those of the quie ...
Constellations and the Galactic Plane
... are all familiar names to northern hemisphere night sky watchers. There are 88 named constellations, each having numerous stars. This exercise takes you through some of the most recognizable ones in the October-November sky in the Bay Area. The patterns of stars remain the same over the ages. That i ...
... are all familiar names to northern hemisphere night sky watchers. There are 88 named constellations, each having numerous stars. This exercise takes you through some of the most recognizable ones in the October-November sky in the Bay Area. The patterns of stars remain the same over the ages. That i ...
Spectroscopy History
... flame. To aid their investigation, Bunsen and Kirchoff developed the first spectroscope. Earlier scientists used a prism to diffract the light source to a separate viewing scope, and detailed measurements were difficult to perform. The spectroscope that Bunsen and Kirchoff developed had an integrate ...
... flame. To aid their investigation, Bunsen and Kirchoff developed the first spectroscope. Earlier scientists used a prism to diffract the light source to a separate viewing scope, and detailed measurements were difficult to perform. The spectroscope that Bunsen and Kirchoff developed had an integrate ...
Encyclopedia of Optical Engineering Stellar Evolution
... In this configuration, the electrons become closely ‘‘stacked’’ in space, separated by the Pauli exclusion principle: No two electrons can have the same four quantum numbers relating to energy and motion in a very tiny volume. Basically, the electrons can only be pushed so close together. The electr ...
... In this configuration, the electrons become closely ‘‘stacked’’ in space, separated by the Pauli exclusion principle: No two electrons can have the same four quantum numbers relating to energy and motion in a very tiny volume. Basically, the electrons can only be pushed so close together. The electr ...
Stellar classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Light from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with absorption lines. Each line indicates an ion of a certain chemical element, with the line strength indicating the abundance of that ion. The relative abundance of the different ions varies with the temperature of the photosphere. The spectral class of a star is a short code summarizing the ionization state, giving an objective measure of the photosphere's temperature and density.Most stars are currently classified under the Morgan–Keenan (MK) system using the letters O, B, A, F, G, K, and M, a sequence from the hottest (O type) to the coolest (M type). Each letter class is then subdivided using a numeric digit with 0 being hottest and 9 being coolest (e.g. A8, A9, F0, F1 form a sequence from hotter to cooler). The sequence has been expanded with classes for other stars and star-like objects that do not fit in the classical system, such class D for white dwarfs and class C for carbon stars.In the MK system a luminosity class is added to the spectral class using Roman numerals. This is based on the width of certain absorption lines in the star's spectrum which vary with the density of the atmosphere and so distinguish giant stars from dwarfs. Luminosity class 0 or Ia+ stars for hypergiants, class I stars for supergiants, class II for bright giants, class III for regular giants, class IV for sub-giants, class V for main-sequence stars, class sd for sub-dwarfs, and class D for white dwarfs. The full spectral class for the Sun is then G2V, indicating a main-sequence star with a temperature around 5,800K.