The formation of young star generations

The new photo by NASA's Spitzer Space Telescope tells us the story of life and death in a family's rich history. On the infamous infrared image is a colorful cosmic cloud called W5, embellished with many brilliant shining stars.

The picture also provides new evidence that massive stars with violent winds and radioactivity can boost the production of new stars.

Xavier Koenig of the Harvard Smithsonian Center for Astrophysics Research in Cambridge, Massachussette said: 'The process of forming stars due to stimulation is still a difficult thing to prove. But our preliminary analyzes show that this phenomenon can explain many generations of stars seen in the W5 region '. Koenig is currently the lead author of a research paper that will be published in the December 1, 2008 issue of the Astrophysical Journal.

The most massive stars in the universe are formed from dense dust clouds . Extremely massive stars have a mass of 15 to 60 times the mass of the sun; they are so big that their material is lost in the form of winds. Extremely hot stars also glow and emit intense radiation. Over time, both the wind and radiation lost the surrounding clouds to create expansion chambers. Astronauts have long suspected that these compartments cause compressed air to form the next generation of stars. As the compartments widened, it was believed that more and more stars formed along the expansion belt of the cavity. The result is the radiant 'genealogical tree' of stars, the oldest star in the center of the cavity, the younger stars far out in the distance.

Evidence for the hypothesis can easily be seen in photographs of star-forming regions, such as W5, Orion or Carina. For example, in the picture of W5 taken with Spitzer telescopes, the most massive stars (some green card lights on the image) are in the center of two empty chambers; Young stars (white and pink) are mounted on a pillar shaped like an elephant's trunk or distributed outside the rim. However, it is possible that young stars just happen to be at the edge of the cavity and are not formed by the stimulation of big stars.

Stellar generations in the infrared image taken from NASA's Spitzer Space Telescope.(Photo: NASA / JPL-Caltech / Harvard-Smithsonian CfA)

Koenig and his colleagues began to test the stimulated star formation hypothesis by studying the age of stars in the W5 region. They use the Spitzer telescope's infrared image to see through the dust clouds and can take a closer look at the different stages of the star's transformations. They found that stars located in the W5 cavity are older than stars distributed outside the perimeter , and they are even older than the latter located farther outside the perimeter. This step-by-step age distribution provides some of the most evident evidence that big stars have helped to form smaller star generations in practice.

Co-author Lori Allen of Harvard Center for Astrophysics - Smithsonia said: 'Our first observation shows that we are looking at one or two generations of stars formed under the action of stars. great. We plan to continue working on more detailed methods of determining the age of stars to find out if there is any special time gap between stars inside and outside the belt. '. Millions of years later from the present moment, the big stars in W5 will die after a horrific explosion. Then they will destroy some of the young stars nearby that are the stars they contributed to the formation.

W5 has an area of ​​sky equivalent to 4 moons, located about 6,500 light from the constellation Cassiopeia. The Spitzer telescope photo was taken over a 24-hour period. The red color is the dust gas that is heated throughout the compartments of the W5 area. Green light is dense clouds, the area with many white nodes is where the youngest stars form. Green spots are older stars in the star-forming cloud, along with unrelated stars located in front of and behind the cloud.

Other authors involved in the study were Robert Gutermuth, who now works at Smith at Northampton, Mass .; Chris Brunt of the University of Exeter, England; James Muzerolle of the University of Arizona, Tucson; and Joseph Hora of the Harvard-Smithsonian Center for Astrophysics.

NASA's Jet Laboratory, Pasadena, Calif. runs the Spitzer program for NASA's director of scientific duties in Washington. Spitzer Science Center of the California Institute of Technology in Pasadena conducted scientific activities. Caltech controlled JPL for NASA.