Ryan

Which of the following properties must be measured to determine the masses of stars in a typical binary system?

- the average separation between the two stars -the period of the orbits of the two stars -the velocities of the two stars (CLICK ALL OF THESE)

How does the total change (final minus initial) in the properties of a protostar from the beginning of this track to its end compare between a star with five times the mass of our Sun, and a star with the mass of our Sun? Careful: this is a logarithmic plot.

-A 5 MSun protostar changes its temperature more than a 1 MSun protostar. -A 5 MSun protostar changes its radius more than a 1 MSun protostar. -A 5 MSun protostar changes its luminosity more than a 1 MSun protostar. ALL

Say you are trying to study the nuclear reactions in the Sun's core by observing photons coming off its surface. How will this random walk affect your results?

-Each photon would have been created a long time ago: it would be impossible to use them to study nuclear reactions as they are happening right now in the Sun's interior. -Each photon may be a different energy than it was when it was created in the nuclear reactions. -Each photon may be a different color than it was when it was created in the nuclear reactions. ALL OF THESE

Phases of the interstellar medium include

-hot, low-density gas. -cold, high-density gas. -cold, low-density gas. ALL

Sirius and its companion orbit around a common center of mass with a period of 50 years. The mass of Sirius is 2.35 times the mass of the Sun. If the orbital velocity of the companion is 2.35 times greater than that of Sirius, what is the mass of the companion?

1 solar masses

Sirius, the brightest star in the sky, is 2.6 parsecs (8.6 light-years) from Earth, giving it a parallax of 0.379 arcseconds. Another bright star, Pollux , has a parallax of 0.097 arcseconds.What is its distance in parsecs? In light-years?

10.309pc 33.649 light years

The following graph shows the number of sunspots counted on the Sun as a function of time.What is the period between the first and second solar cycle on this graph?

11 years

Match the appropriate descriptions of luminosity, temperature, and size of stars to the correct portion of the H-R diagram.

4 blanks, one in each corner top left- hot, large, high density top right- cool, large, high luminosity bottom left- hot, small,lowdensity bottom right- lot largehighdensity

In the binary system shown here, a small blue star orbits a larger red star, moving from left to right in front of the red star. Match the orientation of the stars to the appearance of the light curve of the system.

4 star pics, from left to right one with blue star on left, one w/ blue in front, blue on right, no blue

The ratio of hydrogen atoms (H) to carbon atoms (C) in the Sun's atmosphere is approximately 2,400 to 1. It is reasonable to assume this also applies to molecular clouds. Radio observations show that a molecular cloud contains 100 𝑀⊙M⊙ of carbon monoxide (CO) in a giant molecular cloud. How much carbon is contained in the cloud? Carbon represents 3/7 of the mass of a CO molecule. How much hydrogen is contained in the cloud? Remember that hydrogen weighs about 1/12 of carbon.

42.857𝑀⊙M⊙ 8571.42858𝑀⊙M⊙

On average, how long does it take particles in the solar wind to reach Earth from the Sun if they are traveling at 300 km/s?

5.77 days

From the vantage point of Earth in the diagram shown, how will the parallax of Star A compare to that of Star B?

A. Star A has twice the parallax of Star B.

Label each region of the Sun with the most important process that is happening there.

AEnergy radiates outward at the speed of light. BNuclear fusion reactions create energy. CMoving matter physically transports energy outward. DEnergy is absorbed, left to right: B,D,C,A

Which of the following has contributed most to our understanding of the process of star formation?

Astronomers have observed many different stars at each step of the formation process

The Sun's structure exhibits many distinct layers. Starting from its center, place the layers in order.

Closest to center -Core -Radiative zone -Convective zone -Photosphere -Chromosphere -Corona Farthest from center

The Sun rotates once every 25 days relative to the stars. The Sun rotates once every 27 days relative to Earth. Why are these two numbers different?

Earth moves in its orbit during this time

Place in order the following steps in the fusion of hydrogen into helium.

First Step -Two hydrogen nuclei collide and become 2H.A positron is emitted.A neutrino is emitted. -Two gamma rays are emitted. -One deuterium nucleus and one hydrogen nucleus collide and become 3He.One gamma ray is emitted. -Two 3He collide and become 4He.Two hydrogen nuclei are emitted. Last Step

Energy stored in matter itself—mass energy—can be very powerful. Per Einstein's famous equation E = mc2, energy is equivalent to mass times a constant (the speed of light squared). The speed of light is very large, so just a small amount of mass can result in a very large amount of energy. How can mass turn into energy?Consider the two most common elements in the universe: hydrogen and helium. As shown in this figure, a hydrogen nucleus (where most of its mass is contained) is made of one proton (p). A helium nucleus is made of two protons and two neutrons (n). Nuclear reactions can change what a nucleus is made of.The mass of hydrogen is 1.6726 x 10-27 kg, and the mass of helium is 6.6465 x 10-27 kg. Given this, which of the following nuclear reactions would result in a decrease of total mass, and thus a release of energy, while keeping the same number of particles involved?

Four hydrogen nuclei combine into one helium nucleus.

Based on its position in this H-R diagram, which of the following best describes the complete classification of the Sun?

G2V

Each image shows a part of a star, with the relative strength of its self-gravity and pressure shown by the length of the blue arrow. Match each star with the description of the state it is in.

Hydrostatic equilibrium - 3 red arrows with shortest blue Collapsing - 3 red with longer blue Expanding - 2 red

The interstellar medium is approximately 99 percent gas and 1 percent dust. Yet it is the dust, not the gas, that in some kinds of light blocks our view of the galactic center. Which of these statements, relating to this effect, is not true?

Infrared light is largely blocked by dust.

What is a neutrino? Did the neutrino enter the reaction, or was the neutrino produced in the reaction?

It is an almost massless, neutral particle that is produced in nuclear processes. The neutrino was produced in the reaction.

How does the solar minimum that occurred around 2008 compare to those in the previous solar cycles?

It lasted for a longer period of time.

As a star forms, place the following in order of their occurrence.

Items (6 items) (Drag and drop into the appropriate area) No more items Items in order Start -A cloud contracts under gravity. -A disk forms because angular momentum is conserved. -Nuclear reactions begin and a star is born. -Clumps form from static electricity. -Planetesimals form from collisions. -A wind blows from the central star. End

Assuming that each of the following objects is a typical example of its class, rank them by increasing density. Lower density -Intercloud gas -Interstellar cloud -Molecular cloud -1 MSun protostar -1 MSun star Higher density

Now, rank the same objects by increasing temperature. For spherical objects, use the surface temperature. Lower temperature -Molecular cloud -Interstellar cloud -1 MSun protostar -1 MSun star -Intercloud gas Higher temperature

Why do photons take so much longer than neutrinos to emerge from the Sun?

Photons interact strongly with matter, while neutrinos do not.

Photons and particles that originate in the Sun reach Earth in a wide range of time intervals. Place these in order of their travel times.

Shortest travel time -Photosphere photon -Neutrino -Coronal mass ejection -Core photon Longest travel time

Stars A and B appear equally bright, but star A is twice as far away from us as star B. Which of the following is true?

Star A is 4 times as luminous as star B.

An eclipsing binary system has a primary eclipse (star A is eclipsed by star B) that is deeper than the secondary eclipse (star B is eclipsed by star A). What does this tell you about stars A and B?

Star A is brighter than star B.

Identify the statement that best describes how the latitude of sunspots varies over a sunspot cycle, which is defined to begin at solar minimum

Sunspots are at higher latitudes at the beginning of a cycle, and lower latitudes at the end of the cycle

Albireo, a star in the constellation of Cygnus, is a binary system whose two components can be seen easily with even a small telescope. Viewers describe the brighter star as "golden" and the fainter one as "sapphire blue." What does this tell you about the relative temperatures of the two stars?

The blue star is hotter than the gold star.

How do the temperatures of the brightest stars in the sky compare to the temperature of the nearest stars? How do the luminosities of the brightest stars in the Sky compare to the luminosities of the nearest stars?

The brightest stars are hotter than the nearest stars. The brightest stars are more luminous than the nearest stars.

If a star has very weak hydrogen lines and is blue, what does that most likely mean?

The star is too hot for hydrogen lines to form.

The Hyashi track is a nearly vertical evolutionary track on the H-R diagram. What does the vertical nature of this track tell you about a protostar as it moves along it?

The star remains the same color

Imagine that the binary stars in each of the pictures are observed from a telescope located somewhere below the image. Spectra of both stars are taken, and used to find radial velocities for each, which are graphed as a function of time in the plot (Star 1: pink, outer-most orbit; Star 2: blue, inner-most orbit).Label the plot with the matching orbital positions of the stars at each marked time.

answers from left to right vertical lines with shorter arrow pointing down, horizontal line with shorter arrow pointing right, the other vertical lines, other horizontal

Why don't nuclear fusion reactions, which combine smaller nuclei into a larger nucleus, happen all around us every time atoms come in contact with one another? Gravity attracts particles with mass to one another, but it is extremely weak compared to the electromagnetic force. The strength and direction of the electromagnetic force depends on the charge of the particle. Particles with the same charge repel each other, and particles with opposite charges attract each other. Sort each of the following particles into the appropriate bin according to the electromagnetic force it would feel in the presence of a hydrogen nucleus. The relative charge of each particle is displayed on it. Items (3 images) (Drag and drop into the appropriate area below)

attracted toward - electron repelled away - proton no force felt - neutron

Sort each of the graphs shown into the bin describing the type of spectrum plotted.

emission- rainbow one lower white line planck- one with black absorption - other rainbow with higher white lines

Based on what you have learned about light from previous chapters, how would we determine what this gas in the interstellar medium is made of?

from the wavelength of absorption lines in the spectra of stars whose light passes through the gas

Identify the element whose emission spectrum is shown in the graph by comparing it to the known spectra of five different elements.

helium

This next image is of the same molecular cloud, but taken with a filter selecting a different set of wavelengths. Label the image with the part of the electromagnetic spectrum it was likely imaged in.

infrared

The following diagram shows the details of the proton-proton nuclear reaction chain that occurs in the core of the Sun.

input- hydrogen, electron output- gamma ray, neutrino, helium4 intermediate- helium3, positron, deuterium

Warm neutral hydrogen can be detected because

it emits light when electrons drop through energy levels.

FeedbackSee HintSee Periodic Table The following infrared image shows part of the plane of the Milky Way Galaxy. Identify the region where a molecular cloud (think: dense and cold) will eventually result in the formation of new stars and planets.

it goes in the middle space

The figure here shows two stars orbiting their center of mass in a binary system. As the stars orbit each other, a side view of the system would show changing positions of their absorption lines due to their Doppler shift.Match the absorption spectrum to the correct orientation of the stars. Assume that we are viewing the system from the bottom of each figure.

labeling, top to bottom one with skinnier line on right, one with one line, one with skinnier line on left

Place these images that depict different states of evolution for a planetary system in chronological order.

left to right biggest blob, smaller blob, one with purple, one with solar system

Rank each color of light according to how much will be transmitted through to the other side of the cloud. Use the scroll bar to see all answer and placement options.

left to right purple, blue, green, yellow, orange, red, IR

Label the four general luminosity classes of stars on the H-R diagram.

left to right whit dwarfs, main sequence, supergiants, giants

This H-R diagram shows five possible protostar evolutionary tracks, each one ending

left to right (top to bottom) EACBD A) 20 million years B) 10 billion years C) 800 million years D) 30 billion years E) 4 million years

The Sun's atmosphere produces different types of spectra depending on the conditions of the layer. This graph shows how the temperature changes at different heights above the Sun's surface. Match the types of spectra to the layer in which they are produced.

left to right DBAC AEmission BAbsorption CX-ray emission DContinuous

Label the layers of the Sun as represented in this graph of density and height above the solar surface.

left to rightBCA ACorona BPhotosphere CChromosphere

Sunspots, flares, prominences, and coronal mass ejections are all caused by

magnetic activity on the Sun

What is the single most important property of a star that will determine its evolution?

mass

The physical model of the Sun's interior has been confirmed by observations of

neutrinos and seismic vibrations.

Astronomers determined the composition of the interstellar medium from

observing its emission and absorption lines

If we were to take a snapshot of where the photons are inside the Sun, and which direction they are traveling, we would find that

photons are traveling in all directions.

In astronomy, the term bipolar refers to outflows that

point in opposite directions

The structure of the Sun is determined by both the balance between the forces due to _______ and gravity and the balance between energy generation and energy _______.

pressure, loss

As energy moves out from the Sun's core toward its surface, it first travels by _______, then by _______, and then by _______.

radiation; convection; radiation

The energy required to begin nuclear fusion in a protostar comes from

the gravitational potential energy of the protostar.

This image displays the Planck spectra, or blackbody curves, for four stars at different temperatures. The curves are adjusted so that they have the same brightness at 550 nm. Identify the temperature value for each blackbody curve.

there's 3 blanks on left - from top to bottom 20,000k, 10,000k, 5000k one on right will be 2500k

Sunspots appear dark because

they are cooler than their surroundings.

Label the stars by their relative surface temperature, based on the habitable zones shown in green

top to bottom low, high, midrange

Astronomers use two points in Earth's orbit to get the best possible parallax measurement. Even better measurements would be possible with observations from

two points in the orbit of Mars, separated by half a Martian year.

Place each star, identified by spectral type and luminosity class, in its proper place on the H-R diagram.

very top blank- A0I top left- b0V bottom left- B0WD top right-K5III bottom right-K5V