A nest of the youngest stars ever seen, which hatched from their clouds of gas and dust only 25,000 years ago, has been revealed by ESA’s Herschel Space Observatory. The finding will assist in filling in the gaps in our knowledge of star formation and evolution, bringing us closer to the moment a star is born.
Operating in the wavebands corresponding to the far infrared and submillimetre portions of the electromagnetic spectrum, Herschel was able to penetrate through the cradle of thick gas and dust and get a previously unseen view of a nursery of 15 baby stars, known as protostars, in the largest star forming site near our Solar System – the Orion Molecular Cloud Complex in the constellation of Orion almost 1,600 light years away.
“We have a pretty good understanding of the general process of star formation, but there are many details still lying, literally and figuratively speaking, in the dark,” says Elise Furlan, who works for the National Optical Astronomy Observatory and is currently located at the Infrared Processing and Analysis Center (IPAC) in Pasadena, California. “We know that stars form in dense clouds of gas and dust, which collapse under their own gravity to form a protostar in their core; this protostar keeps accreting material, gets hotter and hotter, and eventually dissipates its natal cloud and becomes a star.”
However, we are still uncertain about what the conditions are like in star-birthing cores, how they influence the forming of a star and how a protostar accretes all of its material, sucking gas from the envelope that surrounds it. “The objects we discovered are among the youngest protostars so they bring us closer to understanding the earliest phase of star formation,” Furlan adds.
The stars remained hidden until the penetrating gaze of Herschel’s Photodetector Array Camera and Spectrometer (PACS), forced them out of hiding. “The Herschel Space Observatory provides us with unique insights since no telescope before covered the far-infrared range at such high sensitivity,” Furlan tells All About Space. “We now know that these young stars, despite being surrounded by very dense envelopes, can be detected at [these wavelengths], which implies that at this young age, they are already quite hot.”
Of the 15 newly uncovered baby stars, 11 are extremely red. “The reddest of these newly discovered protostars (which is the majority of them; they are the ones with a lot of emission at long wavelengths) are probably just a few tens of thousands of years old,” explains Furlan. “It is remarkable that these young infant stars can already be seen in the far-infrared as distinct point sources.” For comparison, a star like our Sun lives up to a ripe old age of around 10 billion years.
Previously, NASA’s Spitzer Space Telescope uncovered seven additional protostars during its job of relentless rummaging through the cosmos peering through its infrared eyes at a Universe dominated by dust and stars.
The Max Planck Institute for Astronomy’s Amelia Stutz, who led the study, says that while astronomers already have a fairly good understanding of the main aspects of star formation, many aspects remain open questions. It is hoped that further studies will help in finding the answers.
“Further observations and detailed studies with telescopes like the Atacama Large Millimetre Array (ALMA) and hopefully in the near future the James Clerk Maxwell Telescope (JCMT), will reveal key aspects of their properties, such as how they are getting their mass and how big, or massive, these envelopes are at this early phase,” she says.
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Images courtesy of ESA/D. Ducros (top) and NASA/ESA/ESO/JPL-Caltech/Max-Planck Institute for Astronomy (bottom)