Stars are fueled by the nuclear fusion of hydrogen to form helium deep in their interiors.

Our Sun will stay in this mature phase (on the main sequence as shown in the Hertzsprung-Russell Diagram) for approximately 10 billion years. Main Sequence StarsĪ star the size of our Sun requires about 50 million years to mature from the beginning of the collapse to adulthood. Observations with NASA's Chandra X-ray Observatory provided a likely explanation: the interaction between the young star's magnetic field and the surrounding gas causes episodic increases in brightness.

When observers around the world pointed their instruments at McNeil's Nebula, they found something interesting - its brightness appears to vary. 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. In some cases, the cloud may not collapse at a steady pace. Not all of this material ends up as part of a star - the remaining dust can become planets, asteroids, or comets or may remain as dust. Smith (University of Arizona)Īs the cloud collapses, a dense, hot core forms and begins gathering dust and gas. The observations of Eta Carinae's light echo are providing new insight into the behavior of powerful massive stars on the brink of detonation.Ĭredit: NOAO, AURA, NSF, and N. 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. Known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star.

As the cloud collapses, the material at the center begins to heat up. 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. A familiar example of such as a dust cloud is the Orion Nebula. Stars are born within the clouds of dust and scattered throughout most galaxies. Consequently, the study of the birth, life, and death of stars is central to the field of astronomy. Moreover, stars are responsible for the manufacture and distribution of heavy elements such as carbon, nitrogen, and oxygen, and their characteristics are intimately tied to the characteristics of the planetary systems that may coalesce about them. 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.

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