The 15 newly observed protostars turned up by surprise in a European Space Agency survey of the biggest site of star formation near our solar system, located in the constellation Orion, NASA reported Tuesday.
The discovery could help scientists understand one of the earliest and least understood phases of star formation, it said.
"Herschel has revealed the largest ensemble of such young stars in a single star-forming region," Amelia Stutz at the Max Planck Institute for Astronomy in Heidelberg, Germany, said. "With these results, we are getting closer to witnessing the moment when a star begins to form."
Stars form in the gravitational collapse of massive clouds of gas and dust, and the transition from diffuse gas to a super-hot star happens relatively quickly by astronomical standards, which makes finding protostars in the first phase of this change difficult, researchers said.
"Previous studies have missed the densest, youngest and potentially most extreme and cold protostars in Orion," Stutz said. "These sources may be able to help us better understand how the process of star formation proceeds at the very earliest stages, when most of the stellar mass is built up and physical conditions are hardest to observe."
The Herschel space telescope was able to observe the protostars in infrared light, which can shine through surrounding gas clouds that block out higher-energy wavelengths including visible light.
"Our observations provide a first glimpse at protostars that have just begun to 'glow' at far-infrared wavelengths," Elise Furlan, a postdoctoral researcher at the National Optical Astronomy Observatory in Tucson, said.