What is the primary constituent of molecular clouds quizlet?
C) hydrogen and helium atoms.
Which of the following types of molecules is the most abundant in an interstellar molecular cloud?
hydrogen (H2) A molecular cloud is an interstellar cloud of gas and dust in which molecules can form, the most common of which is hydrogen (H2).
What happens to the rotation of a molecular cloud?
What happens to the rotation of a molecular cloud as it collapses to form a star? The rotation rate increases and results in a disk of material around a protostar.
What is the CNO cycle quizlet?
The CNO cycle is a nuclear fusion cycle involving carbon, nitrogen, and oxygen. It is a more ecient way of fusing hydrogen into helium and is used by stars more massive than our Sun. You still have the basic equation as the proton-proton chain, but carbon acts like a catalyst in the reaction.
Why is it important for a molecular cloud to be cold for star formation quizlet?
Stars can form when gravity (which pulls things together) exceeds the local pressure (which tends to push atoms apart.) Pressure is higher in hot material and lower in cold material, so colder clouds put up less resistance to gravity and can collapse more readily.
Why are molecules like CO HCN NH3 H2O and H2CO important for studying the interstellar medium?
Why are molecules like CO, HCN, NH3, H2O, and H2CO important for studying the interstellar medium? They allow us to locate and trace out the structure of cool, dark clouds.
In which order did the events forming our solar system occur quizlet?
In which order did the events forming our solar system occur? The solar nebula spun faster and faster and flattened into a rotating disk. Most of the gas was pulled toward the center, where it became hot and dense, forming the Sun.
How are interstellar clouds formed?
Neutral and ionized clouds are sometimes also called diffuse clouds. An interstellar cloud is formed by the gas and dust particles from a red giant in its later life.
What are interstellar clouds made of?
The region between the stars contains interstellar clouds composed primarily of dust and gas. Over 100 molecules (neutrals, ions, and radicals), mostly carbon-containing compounds, have been identified in interstellar molecular clouds.
Why do molecular clouds rotate?
All clouds rotate, at least a little, due to gravitational shearing in the galaxy's disk. And if a cloud rotates, it has angular momentum: And remember that angular momentum is conserved. So if a rotating cloud collapses (r gets smaller) than it must spin faster (v gets bigger).
What happens to clouds that are rotating as they collapse to form stars?
What happens to the rotation of a molecular cloud as it collapses to form a star? The rotation rate increases and results in a disk of material around a protostar.
How does the CNO cycle differ from the proton-proton chain How is it similar quizlet?
The proton-proton chain and the CNO cycle both convert four hydrogen nuclei into one helium nucleus, releasing energy. The CNO cycle is different from the proton-proton chain because it requires carbon to be present to act as a catalyst.
How does the CNO cycle differ from the proton-proton chain select all that apply quizlet?
How does the CNO cycle differ from the proton-proton chain? The CNO cycle requires a higher temperature than the proton-proton chain and the rate of the CNO cycle is more temperature sensitive than the proton-proton chain.
Why is star formation more likely to occur in cold molecular clouds than in regions where the temperature of the interstellar medium is much hotter?
Likely to occur in the cold region of a molecular cloud because the process of formation begins only when the force of gravitation and falling gas become strong enough to overpower the pressure produced by the cold particles that forms the high density cores.
Why is it important for a molecular cloud to be cold for star formation?
In the colder, denser areas, and under the right conditions, stars are formed. Theoretically, in molecular clouds at temperatures of 10 Kelvin, all molecules except hydrogen and helium should be locked into ice on the surface of dust, not freely floating around.
What are the properties of the neutral hydrogen gas that exists in the interstellar medium?
What are the properties of the neutral hydrogen gas that exists in the interstellar medium? Neutral hydrogen dominates the composition of interstellar matter. The hydrogen exists as single atoms of hydrogen at a temperature of about 100 K. Typical densities are 1 atom/cubic centimeter or higher in clouds.
What is the overall dimming of a star’s brightness as the light travels through the ISM called?
The overall dimming of starlight by interstellar matter is called: extinction.
Which event led to the formation of our solar system quizlet?
Which event led to the formation of our solar system? A solar nebula collapsed.
Which order did the events forming our solar system occur?
In which order did the events forming our solar system occur? The solar nebula became hot and dense pulling in more gas. This flattened into a rotating disk. It spun faster and faster, forming the Sun.
Why do interstellar clouds look dark?
molecular cloud, also called dark nebula, interstellar clump or cloud that is opaque because of its internal dust grains. The form of such dark clouds is very irregular: they have no clearly defined outer boundaries and sometimes take on convoluted serpentine shapes because of turbulence.
What is an interstellar cloud quizlet?
interstellar cloud. a discrete, high-density region of the interstellar medium made up mostly of atomic or molecular hydrogen and dust.
What is in a molecular cloud?
Molecular clouds consist mainly of gas and dust but contain many stars as well. The central regions of these clouds are completely hidden from view by dust and would be undetectable except for the far-infrared thermal emission from dust grains and the microwave emissions from the constituent molecules.
How are molecular clouds formed?
Molecular clouds are expected to be formed in limited regions where the mean magnetic field is parallel to the direction of shock wave propagation or in regions where an excessive number of shock wave sweepings are experienced. Therefore, molecular clouds can only be found in limited regions in shells.
What is a collapsing cloud?
A star forms when a molecular cloud collapses under its own gravity forming a dense core sustained by nuclear fusion. This happens only when the force of gravity pulling in exceeds the outward push of pressure.
How did the cloud’s rotation rate change as the cloud collapsed to smaller and smaller radii?
Angular Momentum All clouds rotate, at least a little, due to gravitational shearing in the galaxy's disk. And if a cloud rotates, it has angular momentum: L ~ mrv. And remember that angular momentum is conserved. So if a rotating cloud collapses (r gets smaller) than it must spin faster (v gets bigger).
How does the CNO cycle differ from the proton-proton chain select all that apply How is it similar select all that apply?
How does the CNO cycle differ from the proton-proton chain? (Select all that apply.) The CNO cycle produces a helium nucleus, whereas the proton-proton chain does not. The CNO cycle produces energy, whereas the proton-proton chain does not.
How does the energy produced in one cycle of the CNO cycle compare to that produced in one cycle of the proton-proton chain?
How does the energy produced in one cycle of the CNO cycle compare to that produced in one cycle of the proton-proton chain? The CNO cycle produces the same amount of energy per cycle as the proton-proton chain.
How does the CNO cycle differ from the proton-proton chain select all that apply How is it similar?
The proton-proton chain and the CNO cycle both convert four hydrogen nuclei into one helium nucleus, releasing energy. The CNO cycle is different from the proton-proton chain because it requires carbon to be present to act as a catalyst.
How do the proton-proton chain and the CNO cycle resemble each other how do they differ which is dominant at the highest temperatures and why?
How does the CNO cycle differ from the proton-proton chain? The CNO cycle requires a higher temperature than the proton-proton chain and the rate of the CNO cycle is more temperature sensitive than the proton-proton chain. The CNO cycle requires a higher temperature than the proton-proton chain.
Why is infrared light so useful in finding regions of star formation?
I. THE ROLE OF INFRARED ASTRONOMY The primary role of infrared astronomy in the study of star formation stems from two facts: the ability of infrared light to escape from dusty regions and the tendency of dust around young stellar objects to reach temperatures in the range of 20 to 1500 kelvins.