3 Units of chapter 11 Interstellar matter Star-Forming RegionsDark Dust Clouds The formation of Stars like the sun Stars of other Masses Star clusters

*

4 Question 1 Some regions of the Milky Way’s disk show up dark becausea) there room no stars there. B) stars in that direction are obscured by interstellar gas. C) stars in the direction room obscured through interstellar dust. D) plenty of black holes catch all the starlight behind them. Some regions of the Milky Way’s disk show up dark since Answer: c

*

5 Question 1 Some areas of the Milky Way’s disk appear dark becausea) there space no stars there. B) stars in the direction are obscured by interstellar gas. C) stars in the direction are obscured by interstellar dust. D) many black holes record all the starlight behind them. Some areas of the Milky Way’s disk show up dark due to the fact that Dust grains are around the same size as visible light, and they have the right to scatter or block the shorter wavelengths.

*

6 Interstellar issue The interstellar medium consists of gas and dust.

You are watching: Some regions along the plane of the milky way appear dark because

Gas is atoms and tiny molecules, mainly hydrogen and helium. Dust is much more like soot or smoke; bigger clumps of particles. Dust absorbs light, and also reddens light the gets through. This image shows distinct reddening of stars near the edge of the dust cloud.

*

7 Interstellar matter Dust clouds absorb blue light preferentially; spectral lines do not shift.

*

8 concern 2 once a star’s visible light passes through interstellar dust, the irradiate we view a) is dimmed and reddened. B) appears to twinkle. C) is Doppler shifted. D) turns bluish in color. E) ionizes the dust and creates emission lines. Answer: a

*

9 inquiry 2 once a star’s visible irradiate passes with interstellar dust, the irradiate we see a) is dimmed and also reddened. B) shows up to twinkle. C) is Doppler shifted. D) transforms bluish in color. E) ionizes the dust and also creates emissions lines. The same process results in exorbitant sunsets, as dust in the waiting scatters the Sun’s blue light, leaving dimmer, redder light.

*

10 Question 3 Astronomers usage the hatchet nebula come refer toa) external envelopes of dice stars that drift gently into space. B) remnants the stars that dice by supernova. C) clouds of gas and also dust in interstellar space. D) remote galaxies seen past our Milky Way. E) every one of the above are correct. Astronomers use the hatchet nebula to refer to Answer: e

*

11 Nebula refers to any kind of fuzzy patch – glowing or dark – in the sky.Question 3 a) outer envelopes of dying stars that drift gently right into space. B) remnants of stars that die by supernova. C) clouds that gas and also dust in interstellar space. D) far-off galaxies seen beyond our Milky Way. E) all of the above are correct. Astronomers usage the term nebula to describe Nebula refers to any kind of fuzzy spot – shining or dark – in the sky.

*

12 Star-Forming regions “Nebula” is a basic term provided for fuzzy objects in the sky. Dark nebula: dust cloud emission nebula: glows, because of hot stars

*

13 Question 4 Interstellar gas is composed generally ofa) 90% hydrogen, 9% helium, and 1% more heavier elements. B) molecules consisting of water and CO2. C) 50% hydrogen, 50% helium. D) hydrogen, oxygen, and nitrogen. E) 99% hydrogen, and also 1% more heavier elements. Interstellar gas is composed primarily of Answer: a

*

14 Question 4 Interstellar gas is composed mainly ofa) 90% hydrogen, 9% helium, and 1% heavier elements. B) molecules consisting of water and also CO2. C) 50% hydrogen, 50% helium. D) hydrogen, oxygen, and also nitrogen. E) 99% hydrogen, and also 1% heavier elements. Interstellar gas is composed mainly of The ingredient of interstellar gas mirrors the of the Sun, stars, and also the jovian planets.

*

15 Star-Forming regions These nebulae are very large and have an extremely low density; their size way that their masses are large despite the short density.

*

16 Star-Forming regions This is the main section of the Milky means Galaxy, reflecting several nebulae, areas of star formation.

*

17 Question 5 The reddish shade of emission nebulae suggests thata) gas and dust is relocating away native Earth. B) hydrogen gas is present. C) dying stars have recently exploded. D) cool red stars are covert inside. E) dust is present. The reddish shade of emission nebulae shows that Answer: b

*

18 Glowing hydrogen gas emits red light about the Horsehead nebula.Question 5 a) gas and dust is moving away native Earth. B) hydrogen gas is present. C) dying stars have recently exploded. D) cool red stars are concealed inside. E) dust is present. The reddish shade of emission nebulae shows that glowing hydrogen gas emits red light around the Horsehead nebula.

*

19 Star-Forming regions Emission nebulae generally glow red – this is the Hα line of hydrogen. The dust lanes visible in the previous picture are component of the nebula, and are not as result of intervening clouds.

*

20 Star-Forming Regions exactly how nebulae job-related

*

21 Star-Forming areas There is a strong interaction in between the nebula and the stars in ~ it; the fuzzy locations near the pillars are due to photoevaporation.

*

22 Star-Forming areas Emission nebulae room made of hot, slim gas, i beg your pardon exhibits distinctive emission lines.

*

23 Tarantula Nebula

*

24 Dark Dust Clouds average temperature that dark dust clouds is a few tens that kelvins. These clouds absorb visible irradiate (left), and emit radio wavelength (right).

*

25 Dark Dust Clouds This cloud is an extremely dark, and can be viewed only since of the elevator stars.

*

26 Dark Dust Clouds The Horsehead Nebula is a particularly distinctive dark dust cloud.

*

27 Dark Dust Clouds Interstellar gas emits low-energy radiation, due to a change in the hydrogen atom.

*

28 Question 6 21-centimeter radiation is vital becausea) that is radio waves happen unaffected v clouds of interstellar dust. B) it arises from cool helium gas present throughout space. C) it have the right to be detected v optical telescopes. D) it is produced by protostars. E) it reveals the structure of new stars. 21-centimeter radiation is important due to the fact that Answer: a

*

29 Question 6 21-centimeter radiation is important becausea) its radio waves pass unaffected v clouds the interstellar dust. B) it occurs from cool helium gas current throughout space. C) it deserve to be detected v optical telescopes. D) the is developed by protostars. E) the reveals the structure of new stars. 21-centimeter radiation is important because Cool atom hydrogen gas produce 21-cm radio radiation as its electron “flips” the direction that spin.

*

30 Dark Dust Clouds This is a contour map that H2CO close to the M20 Nebula. Other molecules that deserve to be beneficial for mapping the end these clouds space carbon dioxide and water. Here, the red and also green lines exchange mail to various rotational transitions. (frequencies)

*

31 Dark Dust Clouds These space CO (carbon monoxide) emitting clouds in the external Milky Way, probably corresponding to regions of star formation.

*

32 Question 7 complex molecules in an are are founda) in the photospheres the red gigantic stars. B) mostly inside dense dust clouds. C) in the coronas of stars favor our Sun. D) scattered same throughout interstellar space. E) surrounding energetic young stars. Facility molecules in an are are uncovered Answer: b

*

33 Question 7 facility molecules in room are founda) in the photospheres that red huge stars. B) generally inside thick dust clouds. C) in the coronas that stars prefer our Sun. D) scattered same throughout interstellar space. E) bordering energetic young stars. Complex molecules in an are are discovered A radio telescope photo of the outer part of the Milky Way, revealing molecule cloud complexes.

*

34 The formation of Stars prefer the SunStar development happens when part of a dust cloud begins to contract under its own gravitational force; together it collapses, the center becomes hotter and hotter till nuclear blend begins in the core.

*

35 The formation of Stars like the SunWhen spring at simply a few atoms, the gravitational force is i do not have anything near solid enough to get over the arbitrarily thermal motion. 1057

*

36 The formation of Stars like the SunStars go v a variety of stages in the procedure of creating from an interstellar cloud.

*

37 question 8 a) Clouds fragment right into smaller objects, forming many stars in ~ one time. B) One star forms; other matter goes right into planets, moons, asteroids, & comets. C) Clouds rotate & litter off mass until only enough is left to type one star. How do solitary stars form within large clouds the interstellar gas and dust? Answer: a

*

38 inquiry 8 a) Clouds fragment into smaller objects, forming numerous stars in ~ one time. B) One star forms; other issue goes into planets, moons, asteroids, & comets. C) Clouds revolve & throw off mass until only enough is left to type one star. Just how do single stars type within large clouds of interstellar gas and also dust? The theory of star formation predicts stars in a swarm would kind about the exact same time.

*

39 The development of Stars favor the SunStage 1: Interstellar cloud starts to contract, probably triggered by shock or pressure wave from adjacent star. As it contracts, the cloud fragments into smaller sized pieces.

*

40 The formation of Stars like the SunStage 2: individual cloud fragments start to collapse. Once the thickness is high enough, over there is no additional fragmentation. Phase 3: The interior of the fragment has started heating, and also is around 10,000 K.

*

41 The formation of Stars like the SunThe Orion Nebula is believed to save interstellar clouds in the procedure of condensing, and protostars. Orion Nebula Mosaic

*

42 The formation of Stars favor the SunStage 4: The core of the cloud is currently a protostar, and also makes its first appearance top top the H–R diagram.

*

43 The development of Stars prefer the SunThese jets space being emitted as product condenses onto a protostar.

*

44 The development of Stars like the SunThese protostars space in Orion.

*

45 The development of Stars choose the SunPlanetary formation has begun, yet the protostar is still not in equilibrium – every heating comes from the gravitational collapse.

*

46 The development of Stars favor the SunThe last stages deserve to be followed on the H–R diagram: The protostar’s luminosity decreases also as that temperature rises since it is becoming much more compact.

*

47 The development of Stars favor the SunAt stage 6, the main point reaches 10 million K, and also nuclear combination begins. The protostar has end up being a star. The star continues to contract and also increase in temperature, until it is in equilibrium. This is phase 7: the star has reached the main sequence and will continue to be there as lengthy as it has hydrogen to fuse in that is core.

*

48 Stars of other Masses This H–R diagram reflects the development of stars somewhat an ext and rather less substantial than the Sun. The form of the paths is similar, however they wind increase in various places on the key sequence.

*

49 Stars of various other Masses If the mass of the initial nebular fragment is too small, nuclear combination will never ever begin. These “failed stars” are referred to as brown dwarfs.

*

50 Star Clusters because a single interstellar cloud have the right to produce numerous stars that the very same age and also composition, star clusters are terrific way to research the impact of mass on stellar evolution.

*

51 Star swarm This is a young star cluster dubbed the Pleiades. The H–R diagram of that is stars is on the right. This is an instance of an open cluster.

*

52 Star clusters This is a globular cluster – keep in mind the lack of massive main-sequence stars, and the greatly populated red gigantic region.

*

53 Cluster place

*

54 inquiry 9 a) OB associations. B) molecular cloud complexes. C) aggregates. D) globular clusters. E) hives. An extremely young stars in little clusters the members are recognized as Answer: a

*

55 concern 9 a) OB associations. B) molecular cloud complexes. C) aggregates. D) globular clusters. E) hives. An extremely young stars in tiny clusters of members are well-known as NGC 3603 is a newborn swarm of hot young blue kind O and also B stars – a perfect OB association.

*

56 Star clusters These pictures are thought to display a star swarm in the procedure of formation within the Orion Nebula.

*

57 Question 10 all stars in a stellar swarm have approximately the samea) temperature. B) color. C) distance. D) mass. E) luminosity. Every stars in a stellar cluster have about the very same Answer: c

*

58 Question 10 all stars in a stellar swarm have about the samea) temperature. B) color. C) distance. D) mass. E) luminosity. All stars in a stellar swarm have roughly the very same Stars in the Pleiades cluster differ in temperature, color, mass, and also luminosity, however all lie around 440 light-years away.

*

59 Star swarm The visibility of massive, short-lived O and B stars can profoundly influence their star cluster, together they have the right to blow away dust and gas prior to it has time come collapse. This is a simulation of such a cluster. Carina Nebula

*

60 Question 11 Stars are frequently born within teams known as a) clans.b) spiral waves. C) aggregates. D) clusters. E) swarms. Stars are frequently born within groups known as Answer: d

*

61 Question 11 Stars are regularly born within groups known together a) clans.b) spiral waves. C) aggregates. D) clusters. E) swarms. Stars are regularly born within teams known together The Pleiades – a nearby open swarm – is a team of fairly young stars around 400 light-years indigenous the Sun.

*

62 Question 12 Globular clusters are commonly observeda) in the airplane of ours Galaxy. B) above or below the airplane of our Galaxy. C) close to to ours Sun. D) in the hearts of various other galaxies. Globular swarm are generally observed Answer: b

*

63 Question 12 Globular clusters are generally observeda) in the plane of our Galaxy. B) above or below the airplane of our Galaxy. C) close to to our Sun. D) in the mind of various other galaxies. Globular swarm are frequently observed Globular clusters orbit the facility of the Milky Way, and are usually seen over or listed below the galactic plane far from our Sun.

*

64 Summary of chapter 11 Interstellar tool is make of gas and dust.

See more: Where Did Darius Rucker Go To College, 10 Highest Educated Country Music Stars

Emission nebulae are hot, glow gas linked with the formation of big stars. Dark dust clouds, specifically molecular clouds, are very cold. They might seed the beginnings of star formation. Dark clouds deserve to be studied using the 21-cm emission heat of molecular hydrogen. Star formation starts with fragmenting, collapsing cloud the dust and also gas.

*

65 Summary of chapter 11, cont.The cloud fragment collapses due to its own gravity, and its temperature and luminosity increase. Once the core is sufficiently hot, combination begins. Collapsing cloud fragments and protostars have been observed. Mass determines wherein a star falls on the main sequence. One cloud frequently forms countless stars, together a star cluster.

*