Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2023 September 19
Two jets are seen in red and blue moving out from
a central object shroueded by a diffuse dark brown. The
rest of the frame is dark but with an few bright stars.
Please see the explanation for more detailed information.

HH 211: Jets from a Forming Star
Credit: NASA, ESA, CSA, Webb; Processing: Tom Ray (DIAS Dublin)

Explanation: Do stars always create jets as they form? No one is sure. As a gas cloud gravitationally contracts, it forms a disk that can spin too fast to continue contracting into a protostar. Theorists hypothesize that this spin can be reduced by expelling jets. This speculation coincides with known Herbig-Haro (HH) objects, young stellar objects seen to emit jets -- sometimes in spectacular fashion. Pictured is Herbig-Haro 211, a young star in formation recently imaged by the Webb Space Telescope (JWST) in infrared light and in great detail. Along with the two narrow beams of particles, red shock waves can be seen as the outflows impact existing interstellar gas. The jets of HH 221 will likely change shape as they brighten and fade over the next 100,000 years, as research into the details of star formation continues.

Tomorrow's picture: another star's planets


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