What can we learn about a star from a life track on an HR diagram a how long ago it was born *?
What can we learn about a star from a life track on an H-R diagram? less massive than the Sun. When does a star become a main-sequence star? A star becomes a main-sequence star when the rate of hydrogen fusion within the star's core becomes high enough to balance the rate at which the star radiates energy into space.
During which of the labeled stages is the star generating energy through hydrogen fusion in its central core?
During which of the labeled stages is the star generating energy through hydrogen fusion in its central core? Stage 1 is the star's hydrogen-fusing, main-sequence stage.
What is the general trend in elemental abundance in our galaxy quizlet?
What is the general trend in elemental abundance? Elements with more protons are less abundant and elements with an odd number of protons are less abundant than neighboring elements.
What is the general trend in elemental abundance in our galaxy?
-There is a general trend of increasing abundance with increasing atomic number, but elements with odd atomic numbers tend to be more abundant than those with even atomic numbers. -These abundances fluctuate randomly. -These abundances decrease smoothly from atomic number of 6 to atomic number of 20.
What does the H-R diagram tell us about stars?
Hertzsprung-Russell diagram, also called H-R diagram, in astronomy, graph in which the absolute magnitudes (intrinsic brightness) of stars are plotted against their spectral types (temperatures).
How does the H-R diagram show the life of a star?
The mass of this solar system's sun gives us a unit for measuring other stars' masses. Similarly, the sun's luminosity and surface temperature define the center of the Hertzsprung-Russell Diagram (H-R Diagram). Plotting a star on this chart reliably predicts other qualities of the star, such as mass and age.
When a star has used up all of the hydrogen in its core IT contracts but the rest of the star expands Why?
The star as a whole expands because the energy transport cannot keep up with the shell's increasing energy generation rate, so the thermal energy is trapped in the star and builds up, pushing the surface outward. You just studied 21 terms!
Which main sequence star fuses hydrogen via the proton proton chain?
The Sun, along with main sequence stars below about 1.5 times the mass of the Sun (1.5 M ☉), primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain.
What are the two most abundant elements in main sequence stars?
The Sun is a main sequence star and its chemical composition mainly consists of hydrogen and helium with trace amounts of other elements.
Why are heavy elements with even numbers of protons more abundant than those with odd numbers of protons?
There are two basic reasons why most elements with even Z are more abundant. First, elements with even Z have more isotopes. This can be seen from the nuclide chart. Another reason is that nuclei are especially stable if nucleons can "pair up" with their spins in opposite directions.
Why is hydrogen the most abundant element in the universe?
Hydrogen has one proton, one electron and is the only element with no neutrons, making it the simplest element in the universe. Because of this, Hydrogen is believed to be the most abundant element, accounting for about 90% of the visible universe.
Is hydrogen the most abundant element on Earth?
Hydrogen is the most abundant element in the universe – all of the hydrogen in the universe has its origin in the first few moments after the Big Bang. It is the third most abundant element on the Earth's surface after oxygen and silicon.
What is an HR diagram quizlet?
HR Diagram. A graph that shows the relationship between stars temperature and absolute magnitude.
How do you read the HR diagram?
15:5917:27HR (Hertzsprung Russell) Diagram – how stars are classified … – YouTubeYouTube
What does the HR diagram show?
Hertzsprung-Russell diagram, also called H-R diagram, in astronomy, graph in which the absolute magnitudes (intrinsic brightness) of stars are plotted against their spectral types (temperatures).
What does an HR diagram tell us?
The Hertzsprung-Russell diagram shows the relationship between a star's temperature and its luminosity. It is also often called the H-R diagram or colour-magnitude diagram.
When a star has used up all the hydrogen in its core?
(1) When a star exhausts the hydrogen in its core, it becomes a giant or supergiant. Once a star has used up all the hydrogen in its core, fusion of hydrogen into helium stops. The core starts to contract again (just as it contracted as a protostar, before hydrogen fusion began).
What happens in the core of a massive star when it runs out of hydrogen in its core?
Eventually the core of the star runs out of hydrogen. When that happens, the star can no longer hold up against gravity. Its inner layers start to collapse, which squishes the core, increasing the pressure and temperature in the core of the star.
What is the net loss of hydrogen for each full cycle of proton-proton chain?
In a proton-proton chain, four hydrogen nuclei (protons) are combined to form one helium nucleus; 0.7 percent of the original mass is lost mainly by conversion into heat energy, but some energy escapes in the form of neutrinos (ν).
What other nucleus is formed from the fusion of hydrogen and nitrogen 15?
Nitrogen-15 captures a proton and produces a helium nucleus (alpha particle) and carbon-12, which is where the cycle started.
Which is the second most abundant element in the universe?
Helium Helium is the second-most abundant element in the universe, after hydrogen, and accounts for about 25 percent of the atoms in the universe. Most of the helium in the universe was created in the Big Bang, but it also is the product of hydrogen fusion in stars.
What is the most abundant element in the stars?
hydrogen No one mechanism can account for all the elements; rather, several distinct processes occurring at different epochs during the late evolution of a star have been proposed. After hydrogen, helium is the most abundant element.
Can you think of a reason why the even numbered elements are more abundant than the odd numbered elements?
There are two basic reasons why most elements with even Z are more abundant. First, elements with even Z have more isotopes. This can be seen from the nuclide chart. Another reason is that nuclei are especially stable if nucleons can "pair up" with their spins in opposite directions.
Why are elements of even atomic numbers more abundant than those of odd number atomic numbers?
The cause of this relationship is that nuclei having an even number of protons are more stable than atoms that contain an odd number of protons. During nucleosynthesis in stars atoms that are especially stable have a better chance to survive than atoms whose nuclei are less stable.
Is hydrogen the most abundant element in the universe?
Hydrogen is the most abundant element in the universe, accounting for about 75 percent of its normal matter, and was created in the Big Bang. Helium is an element, usually in the form of a gas, that consists of a nucleus of two protons and two neutrons surrounded by two electrons.
Which hydrogen is most abundant in universe?
Hydrogen is the most abundant element in the Universe; helium is second. Hydrogen and helium are estimated to make up roughly 74% and 24% of all baryonic matter in the universe respectively.
Why is hydrogen most abundant in the universe?
Hydrogen — with just one proton and one electron (it's the only element without a neutron) — is the simplest element in the universe, which explains why it's also the most abundant, Nyman said.
Why is hydrogen most abundant element in universe?
Now if we look at hydrogen we can say that it is the simplest element. It is because it has only one proton and electron but no neutrons. What this means is that it can be formed readily. Thus, making it abundant across the universe.
What does the H-R diagram show?
Hertzsprung-Russell diagram, also called H-R diagram, in astronomy, graph in which the absolute magnitudes (intrinsic brightness) of stars are plotted against their spectral types (temperatures).
What is the H-R diagram what are its axes?
These diagrams, called the Hertzsprung-Russell or HR diagrams, plot luminosity in solar units on the Y axis and stellar temperature on the X axis, as shown below. Notice that the scales are not linear. Hot stars inhabit the left hand side of the diagram, cool stars the right hand side.