Spitzer Telescope Finds Hidden Jet
NASA – NASA’s Spitzer Space Telescope took this image of a baby star sprouting two identical jets (green lines emanating from fuzzy star). The jet on the right had been seen before in visible-light views, but the jet at left — the identical twin to the first jet — could only be seen in detail with Spitzer’s infrared detectors. The left jet was hidden behind a dark cloud, which Spitzer can see through.
The twin jets, in a system called Herbig-Haro 34, are made of identical knots of gas and dust, ejected one after another from the area around the star. By studying the spacing of these knots, and knowing the speed of the jets from previous studies, astronomers were able to determine that the jet to the right of the star punches its material out 4.5 years later than the counter-jet.
The new data also reveal that the area from which the jets originate is contained within a sphere around the star, with a radius of 3 astronomical units. An astronomical unit is the distance between Earth and the sun. Previous studies estimated that the maximum size of this jet-making zone was 10 times larger.
The wispy material is gas and dust. Arc-shaped bow shocks can be seen at the ends of the twin jets. The shocks consist of compressed material in front of the jets.
The Herbig-Haro 34 jets are located at approximately 1,400 light-years away in the Orion constellation. Image Credit: NASA/JPL-Caltech
Preview of a Forthcoming Supernova
NASA’s Hubble Telescope captured an image of Eta Carinae. This image consists of ultraviolet and visible light images from the High Resolution Channel of Hubble’s Advanced Camera for Surveys. The field of view is approximately 30 arcseconds across.
The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.
Although 19th century astronomers did not have telescopes powerful enough to see the 1843 outburst in detail, its effects can be studied today. The huge clouds of matter thrown out a century and a half ago, known as the Homunculus Nebula, have been a regular target for Hubble since its launch in 1990. This image, taken with the Advanced Camera for Surveys High Resolution Channel, is the most detailed yet, and shows how the material from the star was not thrown out in a uniform manner, but forms a huge dumbbell shape.
Eta Carinae is one of the closest stars to Earth that is likely to explode in a supernova in the relatively near future (though in astronomical timescales the “near future” could still be a million years away). When it does, expect an impressive view from Earth, far brighter still than its last outburst: SN 2006gy, the brightest supernova ever observed, came from a star of the same type, though from a galaxy over 200 million light-years away. Image Credit: ESA/NASA