Free Astronomy Magazine May-June 2022

MAY-JUNE 2022 IRAS 17527-2439 could belong to a triple star system sep- arated by more than 300 billion kilometers (almost 200 billion miles). MHO 1502, on the other hand, is embed- ded in a totally differ- ent environment — an area of star forma- tion known as an HII region. The bipolar jet is composed of a chain of knots, sug- gesting that its source, thought to be two stars, has been in- termittently emitting material. These detailed images were captured by the Gemini South Adap- tive Optics Imager (GSAOI), an in- strument on the 8.1-meter-diameter Gemini South telescope. Gemini South is perched on the summit of Cerro Pachón, where dry air and negligible cloud cover provide one of the best observing sites on the planet. Even atop Cerro Pachón, however, atmospheric turbulence causes the stars to blur and twinkle. GSAOI works with GeMs, the Gemini Multi-Conjugate Adaptive Optics System, to cancel out this blurring effect using a technique called adap- tive optics. By monitoring the twin- kling of natural and artificial guide stars up to 800 times a second, GeMs can determine how atmospheric tur- bulence is distorting Gemini South’s observations. A computer uses this information to minutely adjust the shape of deformable mirrors, cancel- ing out the distortions caused by turbulence. In this case, the sharp adaptive optics images have made it possible to recognize more details in each knot of the young stellar jets than in previous studies. T he knotted young stellar jet, MHO 1502, is captured in this image from Chile by the international Gemini Observatory, a Program of NSF’s NOIRLab. The stellar jet is embedded in an area of star formation known as an HII region. The bipolar jet is composed of a chain of knots, suggesting that its source, thought to be two stars, has been intermittently emitting material. These crystal-clear observations were made using the Gemini South telescope’s adaptive optics system, which helps astronomers counteract the blurring effects of atmospheric turbulence. [International Gemini Observatory/NOIRLab/NSF/AURA. Ack.: Image processing: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), M. Za- mani (NSF’s NOIRLab) & D. de Martin (NSF’s NOIRLab)] ASTRO PUBLISHING ! uchus has mythological roots — in ancient Greece it represented a vari- ety of gods and heroes grappling with a serpent. MHO 1502, the jet pictured in the second image, is lo- cated in the constellation of Vela, approximately 2000 light-years away. Most stellar jets are straight but some can be wandering or knot- ted. The shape of the uneven jets is thought to be related to a character- istic of the object or objects that cre- ated them. In the case of the two bipolar jets MHO 2147 and MHO 1502, the stars which created them are obscured from view. In the case of MHO 2147, this young central star, which has the catchy identifier IRAS 17527-2439, is em- bedded in an infrared dark cloud — a cold, dense region of gas that is opaque at the infrared wavelengths represented in this image. The sinu- ous shape of MHO 2147 is caused because the direction of the jet has changed over time, tracing out a gentle curve on either side of the central star. These almost unbroken curves suggest that MHO 2147 has been sculpted by continuous emis- sion from its central source. As- tronomers found that the changing direction (precession) of the jet may be due to the gravitational influence of nearby stars acting on the central star. Their observations suggest that