The age, distribution, and composition of the stars in a galaxy trace the history, dynamics, and evolution of that galaxy. Stars are the most widely recognized astronomical objects, and represent the most fundamental building blocks of galaxies. Kids Fun Facts Corner # 1. Known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star.
In January 2004, an amateur astronomer, James McNeil, discovered a small nebula that appeared unexpectedly near the nebula Messier 78, in the constellation of Orion. Wolf-Rayet stars boast masses at least 20 times that of the sun and burn 4.5 times as hot, yet go supernova within a few million years of reaching main sequence [source: NASA]. For more information and further reading on a stars life cycle, see TAB. Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars.
Consequently, the study of the birth, life, and death of stars is central to the field of astronomy.Stars are born within the clouds of dust and scattered throughout most galaxies. As the cloud collapses, the material at the center begins to heat up. NASA. Instead, stars form by fragmentation, and the fragmentation process determines their masses.” The results also explain, the team says, why observations suggest that objects as different as small brown dwarfs and massive stars have a common formation mechanism. A familiar example of such as a dust cloud is the Orion Nebula. When a star has fused all the hydrogen in its core, nuclear reactions cease. Deprived of the energy production needed to support it, the core begins to collapse into itself and becomes much hotter. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. (April 9, 2010)http://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve/"Wolf-Rayet (WR) stars." Weird & WackyWe use cookies to personalise content and ads, to provide social media features and to analyse our traffic. It is closely related to planet formation, another branch of astronomy. Three-dimensional computer models of star formation predict that the spinning clouds of collapsing gas and dust may break up into two or three blobs; this would explain why the majority the stars in the Milky Way are paired or in groups of multiple stars.As the cloud collapses, a dense, hot core forms and begins gathering dust and gas. You consent to our cookies if you continue to use our website."Stars." Sept. 15, 2004.http://imagine.gsfc.nasa.gov/docs/science/know_l1/wolf.html Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction. The increasingly hot core also pushes the outer layers of the star outward, causing them to expand and cool, transforming the star into a red giant.How do Earth, the planets, and the heliosphere respond?Weather and Atmospheric Dynamics Focus Area Publications and Research HighlightsCarbon Cycle and Ecosystems Focus Area Publications and Research HighlightsIndia overtakes China as top emitter of sulfur dioxideLocal land subsidence increases flood risk in San Francisco BaySea surface salinity could provide new insight into severe stormsSeeing the connection between neighboring volcanoes at depthWarm ocean waters off Greenland put glaciers at more risk It is believed that almost every star has the same chemical composition.
Hydrogen is still available outside the core, so hydrogen fusion continues in a shell surrounding the core. The star will then start its journey through its life cycle from birth to death. Our Sun will stay in this mature phase (on the main sequence as shown in the Hertzsprung-Russell Diagram) for approximately 10 billion years.Stars are fueled by the nuclear fusion of hydrogen to form helium deep in their interiors. Cepheus B, a molecular cloud located in our Milky Galaxy about 2,400 light years from the Earth, provides an excellent model to determine how stars are formed.
Star Life-cycle-Supernovas. Larger, brighter stars burn out far faster, however.