Crystal-clear images of meandering bipolar stellar jets from young stars captured with adaptive optics.
Sinuous stellar jets meander lazily across a field of
stars in new images captured from Chile by the international Gemini
Observatory, a Program of NSF's NOIRLab. The gently curving stellar jets
are the outflow from young stars, and astronomers suspect their
sidewinding appearances are caused by the gravitational attraction of
companion stars. 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.
Young stellar jets are a common by-product of star formation and are thought to be caused by the interplay between the magnetic fields of rotating young stars and the disks of gas surrounding them. These interactions eject twin torrents of ionized gas in opposite directions, such as those pictured 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 international Gemini Observatory, a Program of NSF's NOIRLab, that comprises twin 8.1-meter optical/infrared telescopes on 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 roughly 10,000 light-years from Earth, and lies in the galactic plane of the Milky Way, close to the boundary between the constellations Sagittarius and Ophiuchus. MHO 2147 snakes across a starry backdrop in the image — an appropriately serpentine appearance 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 grappling with a serpent. MHO 1502, the jet pictured in the second image, is located in the constellation of Vela, approximately 2000 light-years away.
Most stellar jets are straight but some can be wandering or knotted.
The shape of the uneven 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 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 embedded in an infrared dark cloud
— a cold, dense region of gas that is opaque at the infrared
wavelengths represented in this image [1]. The sinuous 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 emission from its central source. Astronomers 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 IRAS
17527-2439 could belong to a triple star system separated by more than
300 billion kilometers (almost 200 billion miles).
MHO 1502, on the other hand, is embedded in a totally different environment — 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 detailed images were captured by the Gemini South Adaptive Optics Imager (GSAOI), an instrument 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 adaptive
optics. By monitoring the twinkling of natural and artificial guide
stars up to 800 times a second, GeMs can determine how atmospheric
turbulence is distorting Gemini South’s observations [2]. A computer
uses this information to minutely adjust the shape of deformable
mirrors, canceling 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.
Source: Gemini Observatory
Notes
[1] Astronomical objects can appear very different at different
wavelengths. For example, the dust surrounding newborn stars blocks
visible light but is transparent at 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 at
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 make use of "natural
guide stars" which are bright stars that lie close to the target of an
astronomical observation. Their brightness makes it easy to measure how
atmospheric turbulence is distorting their appearance. Gemini South also
uses artificial guide stars produced by shining powerful lasers into
the upper atmosphere.
Links
Contacts
Leticia Ferrero
Universidad Nacional de Córdoba
Tel: +54 9 351 4331063/4/5 int: 105
Email:lvferrero@unc.edu.ar
Amanda Kocz
NSF’s NOIRLab Communications
Tel: +1 520 318 8591
Email:amanda.kocz@noirlab.edu
