Asteroids and satellites swim through Tadpole Nebula

A new infrared image from NASA's Wide-field Infrared Survey Explorer (WISE) captures two asteroids and a pair of satellites sweeping through a star-forming region known as the Tadpole Nebula.

This image of the Tadpole Nebula and surrounds comprises 25 frames taken at four wavelengths, revealing also a pair of asteroids (rectangular boxes) and satellites (ovals). The large boxes showing enlarged versions of the smaller ones. Infrared light of 3.4 microns is coded blue, 4.6 micron light is cyan, 12 micron light is green and 22 micron light is red. Image: NASA/JPL-Caltech/UCLA/.

The serendipitous observations were made as WISE studied a star-forming region – the Tadpole Nebula – in the Auriga constellation some 12,000 light years from Earth. The nebula is packed full of young stars, some barely one million years old and with masses of over 10 times that of our own Sun, and earns its moniker from the two tadpole-shaped yellow regions of gas in the centre of the nebula. Carved out by the intense ultraviolet radiation that emanates from the hot young stars, the two 'tadpoles' are known as Sim 129 and Sim 130, and their 'heads' are bursting with newborn stars, too.

As WISE took some 25 image frames of the region, it also soaked up the sights of two asteroids. The most prominent of the pair, identified as 1719 Jens, can be seen streaking across the centre of the image and is present in 11 of the frames, its track plotted out as the line of yellow-green dots. This 19 kilometre-wide asteroid resides in the Asteroid Belt, and tumbles around its axis in just under six hours. A second asteroid – 1992 UZ5 – was also seen cruising by the top left edge of the image frame.

The chance observations don't end with asteroids either, for WISE also scooped two satellites, highlighted by the ovals marked on the image above and below the nebula. While the asteroid tracks appear as dots, the satellite motions are recorded as continuous faint green trails, an effect due to the relative speeds and distances of the two sets of objects. That is, the apparent motion of asteroids is slower than the satellites given the asteroids' greater distance, so they appear to jump from one WISE frame to the next.

WISE was launched in December last year and will map the entire sky in infrared light to study the origins and evolution of stellar and planetary systems.