Located in the center of our Milky Way Galaxy, Sagittarius B2 is an enormous molecular cloud of gas and dust roughly 3 million times the mass of the Sun.
Stars, gas and cosmic dust in the Sagittarius B2 molecular cloud glow in near-infrared light, captured by Webb’s NIRCam instrument. Image credit: NASA / ESA / CSA / STScI / A. Ginsburg, University of Florida / N. Budaiev, University of Florida / T. Yoo, University of Florida / A. Pagan, STScI.
Sagittarius B2 resides approximately 27,000 light-years from Earth and just 390 light-years from the Milky Way’s center.
It is the most massive and active star forming cloud in our Galaxy, producing half of the stars created in the Galactic center region despite having only 10 % of the area’s star-making material.
“Sagittarius B2 is located only a few hundred light-years from the supermassive black hole at the heart of the Galaxy called Sagittarius A*, a region densely packed with stars, star-forming clouds, and complex magnetic fields,” Webb astronomers said in a statement.
“The infrared light that Webb detects is able to pass through some of the area’s thick clouds to reveal young stars and the warm dust surrounding them.”
“An analysis of Webb’s data will help unravel enduring mysteries of the star formation process, and why Sagittarius B2 is forming so many more stars than the rest of the Galactic center.”
“However, one of the most notable aspects of Webb’s images of Sagittarius B2 are the portions that remain dark.”
“These ironically empty-looking areas of space are actually so dense with gas and dust that even Webb cannot see through them.”
“These thick clouds are the raw material of future stars and a cocoon for those still too young to shine.”
Webb’s MIRI (Mid-Infrared Instrument) shows the Sagittarius B2 region in mid-infrared light, with warm dust glowing brightly. Image credit: NASA / ESA / CSA / STScI / A. Ginsburg, University of Florida / N. Budaiev, University of Florida / T. Yoo, University of Florida / A. Pagan, STScI.
The high resolution and mid-infrared sensitivity of Webb’s MIRI (Mid-Infrared Instrument) revealed this region in unprecedented detail, including glowing cosmic dust heated by very young massive stars.
The reddest area, known as Sagittarius B2 North (north is to the right in these Webb images), is one of the most molecularly rich regions known, but astronomers have never seen it with such clarity.
The difference longer wavelengths of light make, even within the infrared spectrum, are stark when comparing the images from Webb’s MIRI and NIRCam (Near-Infrared Camera) instruments.
“Glowing gas and dust appear dramatically in mid-infrared light, while all but the brightest stars disappear from view,” the astronomers said.
“In contrast to MIRI, colorful stars steal the show in Webb’s NIRCam image, punctuated occasionally by bright clouds of gas and dust.”
“Further research into these stars will reveal details of their masses and ages, which will help astronomers better understand the process of star formation in this dense, active Galactic center region.”
“Has it been going on for millions of years? Or has some unknown process triggered it only recently?”
“We hope Webb will shed light on why star formation in the Galactic center is so disproportionate.”
“Though the region is stocked with plenty of gaseous raw material, on the whole it is not nearly as productive as Sagittarius B2.”
“While Sagittarius B2 has only 10% of the Galactic center’s gas, it produces 50% of its stars.”
