1. Stellar Nurseries Karena Fiore

2. What is a Stellar Nursery?  Also known as molecular clouds, a stellar nursery is a dense region in space where new stars are made.  A stellar nursery is located within a nebula  These interstellar clouds have high concentrations of molecular hydrogen and helium.  Temperatures range from 10 to 30 K

3. History  Nebulas were first recorded around 150 AD by Ptolemy  The first true nebula was mentioned in 954 by Abd al-Rahman al- Sufi in his Book of Fixed Stars.  The nebula was distinct from surrounding star clusters  Al-Sufi also catalogued other nebulas such as the Omicron Velorum Cluster and Brocchi’s Cluster

4. History  In the late 1700s, the Herschels published three catalogs that listed thousands of nebulas and star clusters they had found  An updated version of the Herschels catalog was published in 1888 by J.L.E. Dreyer  The New General Catalogue (NGC) is a compilation of clusters, nebulas, and galaxies

5. Ways a Stellar Nursery is Formed  A cloud of gas becomes so dense that it collapses under its own gravity  A shockwave from a supernova (ex. The Crab Nebula)  When a low-mass star has lost most of its material, its temperature increases and it emits UV radiation that will ionize the surrounding gas  This is a planetary nebula The Crab Nebula (NGC 1952 )

6. Structure of a Stellar Nursery  It is composed of mainly hydrogen and helium  There are trace amounts of the other elements (under 1%)  There is also plasma (ionized gas) within the nebula  Width of millions of miles to hundreds of light years across  Planetary nebulas have a central star

7. Star Formation  Interstellar clouds are at a state of hydrostatic equilibrium  gas pressure and the internal gravitational forces balance each other  Certain events will happen to trigger star formation  Molecular clouds collide  Shockwaves of a supernova explosion  Galactic collisions  This will trigger a gravitational collapse within the nebula

8. Star Formation  As a molecular cloud fragment collapses under gravity, it becomes a protostar  This is the early stage of a forming star  When a protostar reaches 10 million K in its core, it becomes a main-sequence star  It is now able to undergo hydrogen fusion

9. Stars  Stars are born in clusters because the cloud in which they are formed is thousands of times more massive than each star  Brand new stars are main-sequence stars  High mass stars expand to become giants and supergiants  These stars fuse hydrogen, helium, carbon, oxygen, etc.  Low mass stars eventually become white dwarfs  Outer layers of star have been ejected and nuclear fusion has ceased

10. Life Span of a Stellar Nursery  Nebulas exist for a few million years  The radiation pressure from new stars drive away the gas of a nebula  The dissipated nebula cannot be considered a stellar nursery anymore  There is not enough concentrated hydrogen and helium gas to form new stars

11. Cat’s Paw Nebula (NGC 6334)  In September of 2013, a newly discovered stellar nursery was found approximately 5,500 light years from Earth  It was found with ArTeMiS, a wide-field sub-millimeter- wavelength camera  It can sense interstellar dust grains that can be found inside a nebula

12. Cat’s Paw Nebula (NGC 6334)

13. Bibliography  http://en.wikipedia.org/wiki/Star_formation http://en.wikipedia.org/wiki/Star_formation  http://en.wikipedia.org/wiki/Molecular_cloud http://en.wikipedia.org/wiki/Molecular_cloud  http://en.wikipedia.org/wiki/Nebula http://en.wikipedia.org/wiki/Nebula  http://www.universetoday.com/65067/newly-discovered-stellar-nurseries-in-the- milky-way/ http://www.universetoday.com/65067/newly-discovered-stellar-nurseries-in-the- milky-way/  http://www.kidsastronomy.com/nebulae.htm http://www.kidsastronomy.com/nebulae.htm  www.nasa.gov www.nasa.gov  Bennett, Jeffrey O. The Essential Cosmic Perspective. 5th ed. San Francisco: Addison-Wesley, 2009. Print.  http://news.discovery.com/space/astronomy/cats-paw-nebula-star-forming- region-vista-eso-130925.htm http://news.discovery.com/space/astronomy/cats-paw-nebula-star-forming- region-vista-eso-130925.htm  http://en.wikipedia.org/wiki/Star http://en.wikipedia.org/wiki/Star