Star Formation in the Orion Nebula

This new view of the Orion Nebula shows embryonic stars within extensive gas and dust clouds. Combining far-infrared observations from the Herschel Space Observatory and mid-infrared observations from NASA's Spitzer Space Telescope, the image shows newly forming stars surrounded by remnant gas and dust in the form of discs and larger envelopes.

Data from the PACS instrument on Herschel at wavelengths of 70 and 160 microns (a micron is a millionth of a meter) are shown as green and red, respectively, and reveal emission from the disks and envelopes of the very youngest protostars. Two Spitzer instruments, IRAC and MIPS, were used to obtain images of the same region at 8 and 24 microns, which are combined here as blue. These wavelengths show emission from the hotter regions of discs around somewhat older stars.

The region shown covers roughly 25x25 arcminutes on the sky or 3x3 parsecs at the distance to Orion.

Photo credits: ESA/PACS/NASA/JPL-Caltech/IRAM

Note: For more information, see Fledgling Stars Flicker in the Heart of Orion; also, Young Stars Flicker Amidst Clouds of Gas and Dust.

Water Around CW Leonis

The Herschel infrared space observatory has discovered that ultraviolet starlight is the key ingredient for making water in space. It is the only explanation for why a dying star is surrounded by a gigantic cloud of hot water vapor. Herschel is a European Space Agency mission with important participation from NASA.

Every recipe needs a secret ingredient. When astronomers discovered an unexpected cloud of water vapor around the old star IRC+10216, also known as CW Leonis, using NASA's Submillimeter Wave Astronomy Satellite in 2001, they immediately began searching for the source. Stars like IRC+10216 are known as carbon stars and are thought not to make much water. Initially they suspected the star's heat must be evaporating comets or even dwarf planets to produce the water.

Now, Herschel has revealed that the secret ingredient is ultraviolet light, because the water is too hot to have come from the destruction of icy celestial bodies.

"Models predict that there should be no water in the envelopes around stars like this, so astronomers were puzzled about how it got there," said Paul Goldsmith, the NASA project scientist for Herschel at NASA's Jet Propulsion Laboratory, Pasadena, California. "These Herschel observations confirm the surprising presence of water vapor in what we thought was an astronomical desert."

This research, which was led by Leen Decin of the Katholieke Universiteit Leuven, Belgium, appears in the September 2 issue of Nature.

Photo credit: ESA/PACS/SPIRE Consortia

Note: For the ESA press release about this topic, click here: Herschel Detection Explains the Origin of Water in a Carbon Star.