Stellar nursery in Aquila revealed

Principal Investigator: Ph. André
Key Programme: Gould's Belt

Star formation uncovered (Click on the image for extended caption and credits.)

The earliest stages of star formation, pre-stellar cores and young protostars, emit the bulk of their luminosity in the range 80-400 μm. For this reason Herschel's SPIRE and PACS instruments are ideal for studying this phase of star formation. Gould's Belt traces out several nearby molecular clouds where star formation is prominent.

The cloud in Aquila lies at a distance of around 1000 light years from Earth and the size of the area imaged is around 65 light-years across. Large filaments of cold dust (depicted as red and orange) are seen threading through the region. Embedded within the dusty filaments in this image are 700 condensations of dust and gas that will eventually become stars. About 100 of these are believed to be protostars, the remaining 600 are not sufficiently developed yet to be considered protostars. The two bright regions are areas where large newborn stars are causing hydrogen gas to shine.

In this three-colour composite image, red maps light at 500 μm detected by SPIRE, while green and blue map light at 170 μm and 70 μm respectively, as measured by PACS. The observation on which this image is based was taken on 24 October 2009 during the Science Demonstration Phase.

Makemake: a cool dwarf planet is more complex than expected

Key Programme: TNOs are cool: a survey of the trans-Neptunian region
Principal investigator: Thomas Mueller

One of the coldest known objects in our Solar System has been observed with SPIRE. Makemake, a dwarf planet, appeared much fainter than had been predicted and may be much more complex than had been expected.

SPIRE image of Makemake (Click on the image for extended caption and credits.)

Makemake is the third largest dwarf planet known, with a diameter of around 1500 km. It is currently nearly 8 billion km from the Sun and with a surface temperature of around 30 Kelvin (-240 °C) is one of the coldest objects in the Solar System making it very hard to detect. By taking images with SPIRE 44 hours apart and subtracting the 'before' image from the 'after' image, the background sky is removed. Makemake, having moved in the intervening time, appears twice in the resulting image: once as a 'negative image' and again as a 'positive image'. This result demonstrates the sensitivity of this technique to such faint objects.

Water as a powerful probe of energetic interactions

Key Programme: Water In Star-forming regions with Herschel (WISH)
Principal Investigator: Ewine van Dishoeck (Sterrewacht Leiden)

Water has been detected in three young stellar objects observed with PACS during the Herschel Science Demonstration Phase. These are from a sample of almost 90 young stellar objects that will be observed as part of the Water In Star-forming regions with Herschel (WISH) key programme.

WISH will investigate the physical and chemical structure of star forming regions by focussing on the distribution of water and its related species in regions in which new stars are forming. This process takes place deep inside dark clouds and cannot be studied at optical wavelengths. Spectroscopy with HIFI and PACS provide the best diagnostic tools for this type of investigation.

(Top) PACS image of L1157; (Middle) PACS spectrum of HH46; (Bottom)PACS spectrum of NGC 7129. (Click on images for extended captions and credits.)

Young stars produce powerful jets during their birth, in a process which is not yet fully understood. In the first PACS observations of L1157 (a low mass young stellar object comparable to our Sun when it was a toddler), the water distribution in the environment of this young protostar clearly traces regions along the jets where shocks deposit energy into the clouds surrounding the protostar.

This is the first water map of such a region and beautifully illustrates the power of PACS to 'light up' the interaction of the young star with its surroundings.

Herbig-Haro 46, a classic example of a low mass young stellar object, was also observed with PACS.

Here, the forbidden excitation lines of [OI] were resolved showing that most of this emission is found along the outflow in the high velocity jets. These [OI] lines, which can only be resolved with Herschel, trace regions of shock-excited gas.

Strong water lines were also detected in NGC 7129 (an intermediate mass young stellar object), along with other related trace lines (OH, CO and [OI]). These new observations challenge the current models describing the environment of this object.

The first preliminary results of this small sample of the WISH objects have clearly demonstrated the power of Herschel to probe these poorly understood regions and the role of water in shaping them.