Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may...
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Transcript of Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may...
![Page 1: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/1.jpg)
Galaxies
Astronomy 100
![Page 2: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/2.jpg)
What is a “star cluster”?What is a “star cluster”?
• stars formed together at same time
• stars may be gravitationally bound together
• two types: open (galactic) and globular
Image at http://hubblesite.org/newscenter/archive/releases/star%20cluster/globular/2007/18/image/a/format/web/results/50/
![Page 3: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/3.jpg)
Open ClustersOpen Clusters• dozens to
thousands of stars• young stars! only
a few million years old
• may still be surrounded by nebula from which they formed
• located in the spiral arms of a galaxy
• example: Pleiades
Image at http://hubblesite.org/newscenter/archive/releases/star%20cluster/open/2004/20/image/a/results/50/
![Page 4: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/4.jpg)
More open star clusters
![Page 5: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/5.jpg)
Globular ClustersGlobular Clusters
• millions to hundreds of millions of stars
• old! 6 to 13 billion years• mostly red giants and dwarfs• stars are clumped closely together,
especially near the center of the cluster (densely)
• surround our disk as a halo
Image at http://hubblesite.org/newscenter/archive/releases/star%20cluster/globular/1999/26/image/a/results/50/
![Page 6: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/6.jpg)
What is a “nebula”?What is a “nebula”?
• A cloud in space• Made of gas and dust
– Can have stars inside
• Most of the ones we see are inside our Milky Way Galaxy
• Different types
![Page 7: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/7.jpg)
Large, massive, bright nebulae
Emission NebulaEmission Nebula•The hot gas is emitting lightThe hot gas is emitting light
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Colder, darker nebulaeDark dust blocking Dark dust blocking the hot gas behind the hot gas behind itit
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Leftovers from an Explosion
Supernova remnantSupernova remnant (smaller, less gas) (smaller, less gas)
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What is a “galaxy”?What is a “galaxy”?
• A large group of stars outside of our own Milky Way• Made of billions to trillions of stars– Also may have gas and dust
• Spiral, or elliptical, or irregular shaped
![Page 11: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/11.jpg)
Spiral galaxy--Andromeda
NOAO/AURA/NSF Images at http://www.noao.edu/image_gallery/html/im0606.html and http://www.noao.edu/image_gallery/html/im0685.html
![Page 12: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/12.jpg)
Elliptical Galaxies
![Page 13: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/13.jpg)
Irregular Galaxies
NASA and NOAO/AURA/NSF Images at http://hubblesite.org/newscenter/archive/releases/galaxy/irregular/2005/09/results/50/ , http://www.noao.edu/image_gallery/html/im0560.html , and http://www.noao.edu/image_gallery/html/im0993.html
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Our Galaxy: the Milky WayOur Galaxy: the Milky Way
• has about 200 billion stars, and lots of gas and dust
• is a barred-spiral (we think)• about 100,000 light-years wide• our Sun is halfway to the edge, revolving at
half a million miles per hour around the center of the Galaxy
• takes our Solar System about 200 million years to revolve once around our galaxy
![Page 15: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/15.jpg)
The Milky WayThe Milky Way
![Page 16: Galaxies Astronomy 100. What is a “star cluster”? stars formed together at same time stars may be gravitationally bound together two types: open (galactic)](https://reader035.fdocuments.in/reader035/viewer/2022070409/56649e7c5503460f94b7e51c/html5/thumbnails/16.jpg)
Mapping the Milky Way
We can see: • Stars and star clusters• Nebulae• Galaxies
How do we know what our Galaxy How do we know what our Galaxy looks like?looks like?