Signatures of Star Birth
The glowing, clumpy streams of material shown in these NASA Hubble Space Telescope images are the signposts of star birth.
Ejected episodically by young stars like salvos from a cannon, the blobby material zips along at more than 440,000 miles (770,000 kilometers) an hour. Called Herbig-Haro or HH objects, these speedy outflows have a bumpy ride through space.
When fast-moving blobs "rear-end" slower gas, bow shocks (the blue features) arise as the material heats up. Bow shocks are glowing waves of matter similar to waves produced by the bow of a ship plowing through water. In HH 2, at lower right, several bow shocks (the compact blue and white features) can be seen where fast-moving clumps bunch up like cars in a traffic jam. In HH 34, at lower left, a grouping of merged bow shocks reveals regions that brighten and fade over time as the heated material cools, shown in red, where the shocks intersect.
In HH 47, at top, a long jet of material has burst out of a dark cloud of gas and dust that hides the newly forming star. The blue, fan-shaped region at left is the edge of a cavity illuminated by the fledgling star. A massive clump of jet material collides with upstream gas, creating the white bow-shaped shock wave at right.
These images are part of a series of time-lapse movies astronomers have made showing the outflows' motion over time. The movies were stitched together from images taken over a 14-year period by Hubble's Wide Field Planetary Camera 2. Hubble followed the jets over three epochs. Observations of HH 2 were made from 1994, 1997, and 2007; HH 34 from 1994, 1998, and 2007; and HH 47 from 1994, 1999, and 2008.
The outflows are roughly 1,350 light-years from Earth. HH 34 and HH 2 reside near the Orion Nebula, in the northern sky. HH 47 is located in the southern constellation Vela.