ASTR 200 : Lecture 15 Ensemble Properties of Stars
... `evolutionary track' on the HR diagram of a solarmass star ...
... `evolutionary track' on the HR diagram of a solarmass star ...
The Hertzsprung-Russell Diagram
... Astronomers reasoned that if a star were hotter, it should have a higher luminosity, and a cooler star would be dimmer. As it turns out, most stars fit this pattern. They can be found on the HR Diagram in the large group that stretches across the middle of the diagram. These are called the Main Sequ ...
... Astronomers reasoned that if a star were hotter, it should have a higher luminosity, and a cooler star would be dimmer. As it turns out, most stars fit this pattern. They can be found on the HR Diagram in the large group that stretches across the middle of the diagram. These are called the Main Sequ ...
Lecture 10
... Dinky little stars like Prox Cen will last trillions of years Huge stars like Rigel are gone in a few million There aren’t many large stars out there, because they don’t last. 10,000 O stars of the 100,000,000,000 Milky Way stars ...
... Dinky little stars like Prox Cen will last trillions of years Huge stars like Rigel are gone in a few million There aren’t many large stars out there, because they don’t last. 10,000 O stars of the 100,000,000,000 Milky Way stars ...
molecular clouds
... • Hydrogen and helium are the predominant components of the ISM, but it is enriched with heavier elements from earlier stars (created in stellar fusion and supernova explosions). ...
... • Hydrogen and helium are the predominant components of the ISM, but it is enriched with heavier elements from earlier stars (created in stellar fusion and supernova explosions). ...
Luminosity Classes
... In general the less dense a star is the more luminous it will be (because it has more surface area). Luminosity and the thickness of the absorption lines are combined to group stars into Lumniosity Classes. Luminosity Classes are combined with spectral class to describe Stars. The Sun is Class V so ...
... In general the less dense a star is the more luminous it will be (because it has more surface area). Luminosity and the thickness of the absorption lines are combined to group stars into Lumniosity Classes. Luminosity Classes are combined with spectral class to describe Stars. The Sun is Class V so ...
Test #3
... a. Hydrogen, b. Helium, c. Carbon, d. Oxygen 14. The total mass of a binary system can be calculated from a. the ratio of the angular separation from the center of mass of each of the stars. b. the distance to the binary and its radial velocity. c. the semi major axis and period of the orbit. d. the ...
... a. Hydrogen, b. Helium, c. Carbon, d. Oxygen 14. The total mass of a binary system can be calculated from a. the ratio of the angular separation from the center of mass of each of the stars. b. the distance to the binary and its radial velocity. c. the semi major axis and period of the orbit. d. the ...
Ordinary Stars - Edgewood High School
... Color = yellow Example: The Sun Type K Star: 3,500 - 5,000 K Color = Red Example: Aldebaran Type M Star: < 3,500 K Color = Red Example: Betelgeuse ...
... Color = yellow Example: The Sun Type K Star: 3,500 - 5,000 K Color = Red Example: Aldebaran Type M Star: < 3,500 K Color = Red Example: Betelgeuse ...
ref H-R Spectral types
... It is also the brightest star seen from Earth. One of the two stars that make up what we call “Sirius”,Sirius A is a type A star. ...
... It is also the brightest star seen from Earth. One of the two stars that make up what we call “Sirius”,Sirius A is a type A star. ...
The Stars
... • B: Temperatures from 10,000 to 20,000K. Noticeably blue. Examples: Rigel, in Orion, and Spica, in Virgo. • A: Temperatures from 8000-10,000K. They appear white. Strong absorption lines of hydrogen. Examples: Vega, Altair, Sirius. • F: slightly hotter than the Sun. Absorption lines of metals app ...
... • B: Temperatures from 10,000 to 20,000K. Noticeably blue. Examples: Rigel, in Orion, and Spica, in Virgo. • A: Temperatures from 8000-10,000K. They appear white. Strong absorption lines of hydrogen. Examples: Vega, Altair, Sirius. • F: slightly hotter than the Sun. Absorption lines of metals app ...
Star Formation
... O, A, B were erroneously called ‘early types’ and the F, G, K, and M were ‘late types’ Sub categories B0, B1…B9, A0…A9, etc. ...
... O, A, B were erroneously called ‘early types’ and the F, G, K, and M were ‘late types’ Sub categories B0, B1…B9, A0…A9, etc. ...
Luminosity Classes
... In general the less dense a star is the more luminous it will be (because it has more surface area). Luminosity and the thickness of the absorption lines are combined to group stars into Lumniosity Classes. Luminosity Classes are combined with spectral class to describe Stars. The Sun is Class V so ...
... In general the less dense a star is the more luminous it will be (because it has more surface area). Luminosity and the thickness of the absorption lines are combined to group stars into Lumniosity Classes. Luminosity Classes are combined with spectral class to describe Stars. The Sun is Class V so ...
Sun, Star Types and Luminosity
... b. Energy comes from nuclear fusion as they convert Hydrogen to Helium. c. The sun is a typical Main Sequence star. d. Most stars (about 90%) are Main Sequence Stars. e. For these stars, the hotter, the brighter ...
... b. Energy comes from nuclear fusion as they convert Hydrogen to Helium. c. The sun is a typical Main Sequence star. d. Most stars (about 90%) are Main Sequence Stars. e. For these stars, the hotter, the brighter ...
H-R Diagrams
... will show up on the Main Sequence – i.e., what spectral type the star will have while on the main sequence ...
... will show up on the Main Sequence – i.e., what spectral type the star will have while on the main sequence ...
Lecture 16
... thus, A,B,C,... → weaker lines. A later scheme, called the B-V Index, classed stars according to a logarithmic ratio of the peak amount of radiation in the blue and violet colors. The current scheme is to class stars according to color in a way which is more or less logarithmically proportional to t ...
... thus, A,B,C,... → weaker lines. A later scheme, called the B-V Index, classed stars according to a logarithmic ratio of the peak amount of radiation in the blue and violet colors. The current scheme is to class stars according to color in a way which is more or less logarithmically proportional to t ...
Stellar_Evol
... Basic Structure The more massive the star the hotter it is, the hotter it is the brighter it burns • Mass is the most important • Determines brightness, temperature & diameter (volume) ...
... Basic Structure The more massive the star the hotter it is, the hotter it is the brighter it burns • Mass is the most important • Determines brightness, temperature & diameter (volume) ...
File
... 8. A device that breaks light into colors and produces an image is a(n) 9. A unit that is often used to measure distances between stars is a(n) 10. The region of the Hertzsprung-Russell diagram that most stars fall within is the ______________________ . 11. A graph of stars showing surface temperatu ...
... 8. A device that breaks light into colors and produces an image is a(n) 9. A unit that is often used to measure distances between stars is a(n) 10. The region of the Hertzsprung-Russell diagram that most stars fall within is the ______________________ . 11. A graph of stars showing surface temperatu ...
Astronomical terms and constants
... MB = absolute blue magnitude of a star; B indicates that we are referring to that part of stellar radiation that is emitted in the “blue” part of the spectrum, i.e. at about 4 × 10−5 cm, 4000 Å. mbol = Mbol + 5 log (d/10pc) = apparent bolometric magnitude of a star at a distance d . V = MV + 5 log ...
... MB = absolute blue magnitude of a star; B indicates that we are referring to that part of stellar radiation that is emitted in the “blue” part of the spectrum, i.e. at about 4 × 10−5 cm, 4000 Å. mbol = Mbol + 5 log (d/10pc) = apparent bolometric magnitude of a star at a distance d . V = MV + 5 log ...
Homework, August 29, 2002 AST110-6
... 3. Is this statement sensible? Why, or why not? (20pt) If the Sun had been born as a high-mass star some 4.6 billion years ago, rather than as a low mass star, the planet Jupiter would probably have Earth-like conditions today, while earth would be hot like Venus. 4. Chapter 11, Problem 26. Stellar ...
... 3. Is this statement sensible? Why, or why not? (20pt) If the Sun had been born as a high-mass star some 4.6 billion years ago, rather than as a low mass star, the planet Jupiter would probably have Earth-like conditions today, while earth would be hot like Venus. 4. Chapter 11, Problem 26. Stellar ...
Notes - CH 12
... A supergiant star can explode before it dies The debris is still visible as an interstellar cloud ...
... A supergiant star can explode before it dies The debris is still visible as an interstellar cloud ...
Chapter 27.2
... Giants and Supergiants • 3rd stage, when hydrogen in the star’s core is exhausted. Hydrogen fusion continues in the star’s outer layers. • Core contracts due to gravity, and its temperature increases. • Helium in the core fuses into ...
... Giants and Supergiants • 3rd stage, when hydrogen in the star’s core is exhausted. Hydrogen fusion continues in the star’s outer layers. • Core contracts due to gravity, and its temperature increases. • Helium in the core fuses into ...
Before Reading
... Day 1: What is one fact you know about stars? What is one question you have about stars? Day 2: The coyote is often described as clever. What word would you use to describe a lion? a monkey? an eagle? Day 3: If you had to describe our sun using just 5 words, what words would you choose? ...
... Day 1: What is one fact you know about stars? What is one question you have about stars? Day 2: The coyote is often described as clever. What word would you use to describe a lion? a monkey? an eagle? Day 3: If you had to describe our sun using just 5 words, what words would you choose? ...
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.