Crystal-clear images of meandering bipolar stellar jets of young stars captured with adaptive optics

Meandering stellar jets meander lazily through a star field in new images captured from Chile by the Gemini International Observatory, a program of NSF’s NOIRLab. The gently curved stellar jets are the outflow of young stars, and astronomers suspect that their sideways appearances are caused by the gravitational pull of companion stars. These crystal-clear observations were made using the Gemini South telescope’s adaptive optics system, which helps astronomers counteract the hazy effects of atmospheric turbulence.

Young stellar jets are a common by-product of star formation and are thought to be caused by the interaction between the magnetic fields of rotating young stars and the discs of gas around them. These interactions eject twin torrents of ionized gas in opposite directions, like those shown in two images captured by astronomers using the Gemini South telescope on Cerro Pachón on the edge of the Chilean Andes. Gemini South is one half of the Gemini International Observatory, a program of NSF’s NOIRLab, which includes twin 8.1-meter optical/infrared telescopes at two of the best observing sites on the planet. Its counterpart, Gemini North, is located near the summit of Maunakea in Hawai’i.

The jet in the first image, named MHO 2147, is about 10,000 light-years from Earth and lies within the galactic plane of the Milky Way, near the boundary between the constellations of Sagittarius and Ophiuchus. MHO 2147 snakes against a starry background in the image — a serpentine appearance appropriate for an object close to Ophiuchus. Like many of the 88 modern astronomical constellations, Ophiuchus has mythological roots – in ancient Greece it represented a variety of gods and heroes wrestling with a serpent. MHO 1502, the jet shown in the second image, is located in the constellation of Vela, about 2000 light years away.

Most star jets are straight but some can be stray or knotted. The shape of the jagged jets is thought to be related to a characteristic of the object or objects that created them. In the case of the two bipolar jets MHO 2147 and MHO 1502, the stars that created them are occulted.

In the case of MHO 2147, this central young star, which bears the catchy identifier IRAS 17527-2439, is embedded in an infrared black cloud — a region of cool, dense gas that is opaque to the infrared wavelengths shown in this image. [1]. The curvy shape of MHO 2147 is due to the direction of the jet changing over time, tracing a gentle curve on either side of the central star. These almost uninterrupted curves suggest that MHO 2147 was sculpted by continuous emission from its central source. Astronomers have discovered that the change in direction (precession) of the jet may be due to the gravitational influence of nearby stars acting on the central star. Their observations suggest that IRAS 17527-2439 may belong to a system of triple stars separated by more than 300 billion kilometers (nearly 200 billion miles).

MHO 1502, on the other hand, is embedded in a totally different environment – a star forming area known as the HII region. The bipolar jet is made up of a string of nodes, suggesting that its source, thought to be two stars, emits material intermittently.

These detailed images were captured by the Gemini South Adaptive Optics Imager (GSAOI), an instrument of the 8.1-meter-diameter Gemini South Telescope. Gemini South is perched atop Cerro Pachón, where dry air and negligible cloud cover make for one of the best viewing spots on the planet. Even atop Cerro Pachón, however, atmospheric turbulence causes the stars to blur and twinkle.

GSAOI works with GeMs, the Gemini Multiconjugate Adaptive Optics System, to cancel out this blurring effect using a technique called adaptive optics. By monitoring the twinkling of natural and man-made guide stars up to 800 times per second, GeMs can determine how atmospheric turbulence is distorting Gemini South observations [2]. A computer uses this information to fine-tune the shape of the deformable mirrors, canceling out the distortions caused by turbulence. In this case, the sharp adaptive optics images allowed more detail to be recognized in each node of the young stellar jets than in previous studies.


[1] Astronomical objects can appear very different at different wavelengths. For example, the dust surrounding newborn stars blocks visible light but is transparent to infrared wavelengths. Something similar also happens here on Earth – doctors can see right through you with an x-ray machine even though human bodies are not transparent to visible wavelengths. Astronomers therefore study the Universe across the electromagnetic spectrum to learn as much as possible about the Universe.

[2] Adaptive optics systems on telescopes often use “natural guide stars”, which are bright stars located close to the target of an astronomical observation. Their brightness makes it easy to measure how much atmospheric turbulence distorts their appearance. Gemini South also uses artificial guide stars produced by shooting powerful lasers into the upper atmosphere.

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