Throes Of Stellar Birth Revealed As Never Before
November 12, 2013

Bubbly Newborn Star Captured By Spitzer And ALMA

April Flowers for - Your Universe Online

The bubbly birth of a bouncing baby star has been revealed by observations from NASA's Spitzer Space Telescope and the newly completed Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. For the well-studied object known as HH 46/47, the observations have revealed the mechanisms of stellar birth as never before seen.

HH, or Herbig-Haro, objects form when jets pushed out by newborn stars collide with material surrounding them. This produces small, bright, nebulous regions. Enveloping gas and dust obscure the dynamics within many HH objects to the naked eye. The infrared light observed by Spitzer, and the submillimeter wavelengths of light seen by ALMA, however, pierce the dark cosmic cloud around HH 46/47 to let us in on the action.

Twin supersonic jets emanating from the central star were revealed by Spitzer. These jets blast away surrounding gas and set it alight into two bubbly lobes. HH 46/47 sits on the edge of its enveloping gas cloud so that the jets pass through two differing cosmic environments. The jet to the right heads into the cloud, plowing through a "wall" of material. The left jet, in contrast, has a relatively unobstructed path, passing through significantly less material. This has important implications for the researchers, allowing them to compare and contrast the outflows from a developing star intact with their surroundings.

"Young stars like our sun need to remove some of the gas collapsing in on them to become stable, and HH 46/47 is an excellent laboratory for studying this outflow process," said Alberto Noriega-Crespo, a scientist at the Infrared Processing and Analysis Center at the California Institute of Technology (CalTech). "Thanks to Spitzer, the HH 46/47 outflow is considered one of the best examples of a jet being present with an expanding bubble-like structure."

Noriega-Crespo and a team of researchers began studying HH 46/47 almost a decade ago when Spitzer first began observations. A new image processing technique developed in the past few years has allowed the team to render HH 46/47 in higher resolution.

New observations of HH 46/47 from ALMA has revealed that the gas in the lobes is expanding faster than scientists previously thought. This rapid expansion influences the overall amount of turbulence in the gas cloud that originally spawned the star. The extra turbulence, in turn, could have an impact on whether and how other stars might form in this gaseous, dusty, and thus fertile, ground for star-making.

The ALMA observations and analysis was led by Hector Arce from Yale University. The analysis was recently published in The Astrophysical Journal.