The Bigger Picture - Astronomy and Astrophysics
... • The different spectral types were recognized in the early 1800s. • Why do some stars show strong absorption due to hydrogen and others don’t. • The obvious solution would be to imagine that it is due to differences in the chemical composition of stars. Nope! ...
... • The different spectral types were recognized in the early 1800s. • Why do some stars show strong absorption due to hydrogen and others don’t. • The obvious solution would be to imagine that it is due to differences in the chemical composition of stars. Nope! ...
Foundation 1 - Discovering Astronomy
... So what is the fate of out Sun? • Since the Sun has a mass less than 8 M and since it is alone without a companion, it will become a White Dwarf and then slowly cool into a Black Dwarf ...
... So what is the fate of out Sun? • Since the Sun has a mass less than 8 M and since it is alone without a companion, it will become a White Dwarf and then slowly cool into a Black Dwarf ...
across
... energy came from gravity- the Sun was converting gravitational energy to heat. Egrav=GMm/R. So as R get smaller, energy can be released. Lord Kelvin estimated the Sun could last 30 million years based on this. ...
... energy came from gravity- the Sun was converting gravitational energy to heat. Egrav=GMm/R. So as R get smaller, energy can be released. Lord Kelvin estimated the Sun could last 30 million years based on this. ...
Chapter 28 Stars and Their Characteristics
... – So…A smaller star has less fuel, but its rate of fusion is not as fast. Therefore, smaller stars live longer than larger stars because their rate of fuel consumption is not as rapid. ...
... – So…A smaller star has less fuel, but its rate of fusion is not as fast. Therefore, smaller stars live longer than larger stars because their rate of fuel consumption is not as rapid. ...
chapter 14 - Astronomy
... 1. A binary system of a white dwarf and a newly formed red giant will result in the formation of an accretion disk around the white dwarf. The material in the disk comes from the red giant and is mostly hydrogen. 2. An accretion disk is a rotating disk of gas orbiting a star, formed by material fall ...
... 1. A binary system of a white dwarf and a newly formed red giant will result in the formation of an accretion disk around the white dwarf. The material in the disk comes from the red giant and is mostly hydrogen. 2. An accretion disk is a rotating disk of gas orbiting a star, formed by material fall ...
Multiple Choice, continued
... hydrogen atoms within its core have fused into helium atoms. Giant Stars • A star’s shell of gases grows cooler as it expands. As the gases in the outer shell become cooler, they begin to glow with a reddish color. These stars are known as giants. • giant a very large and bright star whose hot core ...
... hydrogen atoms within its core have fused into helium atoms. Giant Stars • A star’s shell of gases grows cooler as it expands. As the gases in the outer shell become cooler, they begin to glow with a reddish color. These stars are known as giants. • giant a very large and bright star whose hot core ...
File
... hydrogen atoms within its core have fused into helium atoms. Giant Stars • A star’s shell of gases grows cooler as it expands. As the gases in the outer shell become cooler, they begin to glow with a reddish color. These stars are known as giants. • giant a very large and bright star whose hot core ...
... hydrogen atoms within its core have fused into helium atoms. Giant Stars • A star’s shell of gases grows cooler as it expands. As the gases in the outer shell become cooler, they begin to glow with a reddish color. These stars are known as giants. • giant a very large and bright star whose hot core ...
Pulsating Variable Stars and The Hertzsprung - Chandra X
... the absolute magnitude (MV) – intrinsic brightness – of stars is plotted against their temperature (stellar classification) the stars are not randomly distributed on the graph but are mostly restricted to a few well-defined regions. The stars within the same regions share a common set of characteris ...
... the absolute magnitude (MV) – intrinsic brightness – of stars is plotted against their temperature (stellar classification) the stars are not randomly distributed on the graph but are mostly restricted to a few well-defined regions. The stars within the same regions share a common set of characteris ...
Lec2015_22
... • Post asymptotic giant branch star (a few have [Fe/H]=-4.8) where various elements (Fe, Ca, Mg) have formed dust grains which have then be lost via mass-loss (Eddington Luminosity for dust grains low). However, other elements do not deplete onto dust and C, N, O and Zn should have ~Solar abundances ...
... • Post asymptotic giant branch star (a few have [Fe/H]=-4.8) where various elements (Fe, Ca, Mg) have formed dust grains which have then be lost via mass-loss (Eddington Luminosity for dust grains low). However, other elements do not deplete onto dust and C, N, O and Zn should have ~Solar abundances ...
Stellar Census
... true star must be at least 1/12 that of the Sun A “true” star is one that becomes hot enough to fuse protons to form helium (see Ch. 15) ...
... true star must be at least 1/12 that of the Sun A “true” star is one that becomes hot enough to fuse protons to form helium (see Ch. 15) ...
Stellar Evolution Review
... 13-12. A one solar mass star will a) go through a red giant phase and end its life as a white dwarf. b) not go through a red giant phase and end its life as a white dwarf. c) go through a red giant phase and end its life as a black hole. d) not go through a red giant phase and end its life as a bla ...
... 13-12. A one solar mass star will a) go through a red giant phase and end its life as a white dwarf. b) not go through a red giant phase and end its life as a white dwarf. c) go through a red giant phase and end its life as a black hole. d) not go through a red giant phase and end its life as a bla ...
star-formation rate
... The colors of Sc spirals, for example, are not compatible with a constant starformation rate – except if the total light of spirals is strongly reddened by dust absorption (but there are good reasons why this is not the case). ...
... The colors of Sc spirals, for example, are not compatible with a constant starformation rate – except if the total light of spirals is strongly reddened by dust absorption (but there are good reasons why this is not the case). ...
Chapter 07
... many stars have no lines for hydrogen or helium in their spectrum. What causes this apparent contradiction? a. Spectral lines are created in the lower atmospheres of stars, and for many stars hydrogen and helium are hidden below the atmosphere. b. The upper layers of a star contain hot low-density g ...
... many stars have no lines for hydrogen or helium in their spectrum. What causes this apparent contradiction? a. Spectral lines are created in the lower atmospheres of stars, and for many stars hydrogen and helium are hidden below the atmosphere. b. The upper layers of a star contain hot low-density g ...
Measuring the Properties of Stars - Sierra College Astronomy Home
... Knowledge of the size of one of the star’s ellipses, along with knowledge of the period of its motion, permits calculation of the total mass of the two stars. To determine how the system’s total mass is distributed between the two stars, one need only consider the ratio of the two stars’ distances t ...
... Knowledge of the size of one of the star’s ellipses, along with knowledge of the period of its motion, permits calculation of the total mass of the two stars. To determine how the system’s total mass is distributed between the two stars, one need only consider the ratio of the two stars’ distances t ...
Properties of Stars - Indiana State University
... groups according to their color (white, yellow, red, and deep red), which were subsequently subdivided into classes using the letters A through N ...
... groups according to their color (white, yellow, red, and deep red), which were subsequently subdivided into classes using the letters A through N ...
STAR FORMATION
... • The core of the contracting cloudlet heats up -- but still not hot enough to begin nuclear fusion. • This protostellar period lasts for < 1 percent of the star's total life on the Main Sequence (i.e. ~3x107 yr for the Sun, whose total lifespan is ~ 10 billion yr.) • Much luminosity is generated in ...
... • The core of the contracting cloudlet heats up -- but still not hot enough to begin nuclear fusion. • This protostellar period lasts for < 1 percent of the star's total life on the Main Sequence (i.e. ~3x107 yr for the Sun, whose total lifespan is ~ 10 billion yr.) • Much luminosity is generated in ...
Lecture 30
... higher temperatures for nuclear burning of heavier elements: • Initially, burn hydrogen in the core • Once hydrogen is exhausted, too cool to burn helium • Core contracts, heats up • Helium burning stars • If star is massive enough, sequence repeats for carbon burning, then oxygen, silicon etc… Domi ...
... higher temperatures for nuclear burning of heavier elements: • Initially, burn hydrogen in the core • Once hydrogen is exhausted, too cool to burn helium • Core contracts, heats up • Helium burning stars • If star is massive enough, sequence repeats for carbon burning, then oxygen, silicon etc… Domi ...
Properties of Stars - Montana State University Extended University
... O-type star? How many times cooler than the Sun is the coolest M-type star? 10. What fraction of the stars are main sequence stars? 11. What is the range of temperatures found on the surface of main sequence stars? 12. What is the range of luminosities produced by main sequence stars? Compare them t ...
... O-type star? How many times cooler than the Sun is the coolest M-type star? 10. What fraction of the stars are main sequence stars? 11. What is the range of temperatures found on the surface of main sequence stars? 12. What is the range of luminosities produced by main sequence stars? Compare them t ...
Document
... maximum radiation pressure drives it outwards where it can accumulate and become overabundant • If an element has few absorption lines near flux maximum radiation it sinks under its own weight and can become underabundant ...
... maximum radiation pressure drives it outwards where it can accumulate and become overabundant • If an element has few absorption lines near flux maximum radiation it sinks under its own weight and can become underabundant ...
Smashing White Dwarfs
... Near maximum light, spectra are characterized by O-Ca at high velocity (~20k km/s). ...
... Near maximum light, spectra are characterized by O-Ca at high velocity (~20k km/s). ...
THE SPECTRA OF FIVE IRREGULAR VARIABLE STARS George H
... at Mount Wilson, who stated that, "This object is beyond doubt a planetary nebula; whether it is actually variable should be investigated/' Four slit spectrograms of V567 Sagittarii have been obtained at Lick. The spectrum is certainly very similar to that of a planetary nebula, with strong bright l ...
... at Mount Wilson, who stated that, "This object is beyond doubt a planetary nebula; whether it is actually variable should be investigated/' Four slit spectrograms of V567 Sagittarii have been obtained at Lick. The spectrum is certainly very similar to that of a planetary nebula, with strong bright l ...
High Mass Stars
... – From H-R diagram its luminosity is 100000 times greater than the Sun’s. – It therefore burns fuel (uses it’s mass) 100000 times faster than the Sun. – It has 25 times the mass of the Sun so its lifetime will be 25/100000 = 0.00025 times than the Sun’s lifetime = 2.5 million years. ...
... – From H-R diagram its luminosity is 100000 times greater than the Sun’s. – It therefore burns fuel (uses it’s mass) 100000 times faster than the Sun. – It has 25 times the mass of the Sun so its lifetime will be 25/100000 = 0.00025 times than the Sun’s lifetime = 2.5 million years. ...
Stellar Lives (continued). Galaxies.
... They transfer the momentum to anything the run into. The result is radiation pressure. Radiation pressure is responsible for strong stellar winds in massive stars. ...
... They transfer the momentum to anything the run into. The result is radiation pressure. Radiation pressure is responsible for strong stellar winds in massive stars. ...
Stars, Galaxies, and the Universe Section 1
... Stellar Motion Apparent Motion • The apparent motion of stars is the motion visible to the unaided eye. Apparent motion is caused by the movement of Earth. • The rotation of Earth causes the apparent motion of stars to be as though the stars are moving counterclockwise around the North Star. • Earth ...
... Stellar Motion Apparent Motion • The apparent motion of stars is the motion visible to the unaided eye. Apparent motion is caused by the movement of Earth. • The rotation of Earth causes the apparent motion of stars to be as though the stars are moving counterclockwise around the North Star. • Earth ...
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.