Gemini Spies Strong Stellar Gusts in Nearby Massive Star
July 23, 2001
A dramatic infrared image released today by the Gemini Observatorysheds new light on the early stages of the formation of giant stars inour galaxy. The image, taken by the Gemini North telescope onHawaii's Mauna Kea, reveals remarkable details in a nebula of gas anddust expelled from a young star named AFGL 2591. This expulsion is acommon feature in the formation of stars similar in size to the Sun,but it is far less common in their massive counterparts.
"Almost everything in this set of infrared images would be invisiblewith an optical telescope, since it is occurring within a densemolecular cloud of gas and dust," says Gemini scientist Colin Aspin,who made the observation. "Gemini's unparalleled sensitivity andresolution in the infrared allows us to move beyond simply detectingsuch structures in general to being able to study them in greatdetail."
AFGL 2591 is located within the Milky Way more than 3,000 light-yearsfrom Earth, in the constellation of Cygnus. Over the course of thelast few thousand years, it has created a vast expanding nebula largerthan 500 times the diameter of our solar system. The star is at least10 times the size of the Sun, and over 20,000 times as bright, butperhaps only one million years old.
The wispy white and blue structure in the expanding nebula to theright of the young star is a huge outflow of gas and dust driven bythe infall of material onto the star's surface. Gemini scientistsbelieve that the outflow is likely occurring symmetrically around thestar - a second giant-sized expanding nebula to the left of the staris hidden from view by a dense and extensive disk (or torus) ofmaterial encircling AFGL 2591.
"We strongly suspect the outflow occurs on both sides of the star in abipolar structure, because we detect faint traces of gas at thatlocation which indicate interactions between the outflowing gas andthe material forming the parent molecular cloud," says Aspin, ascientific staff member at the Gemini Observatory InternationalHeadquarters in Hilo, HI.
"A unique feature of this object is a series of four distinct rings ofnebulosity. These rings suggest that the expulsion of the material isnot constant with time, but rather has occurred several times over thelifetime of the object," he adds. "Studying the structure andvelocity of these rings, and their relation to the infalling material,will allow us to better understand why such features are created andwhat functions they serve."
This striking image is part of a series of early images taken with theGemini Near Infrared Imager (NIRI) instrument during its commissioningon the Gemini North telescope. Once fully operational later thisyear, NIRI will be the prime near-infrared instrument on GeminiNorth.
The color image and others that show hints of the left-hand outflowand more details in the right-hand structure are available on theInternet in various file sizes (different files will go here).
The Gemini Observatory is an international collaboration that hasbuilt two identical 8-meter telescopes. The telescopes are located atMauna Kea, Hawaii, (Gemini North) and Cerro Pachón in centralChile (Gemini South), and hence provide full coverage of bothhemispheres of the sky. Both telescopes incorporate new technologiesthat allow large, relatively thin mirrors under active control tocollect and focus both optical and infrared radiation from space.Gemini North recently began science operations and Gemini South isscheduled to begin scientific operations in August 2001.
The Gemini Observatory provides the astronomical communities in eachpartner country with state-of-the-art astronomical facilities thatallocates observing time in proportion to each country'scontribution. In addition to financial support, each country alsocontributes significant scientific and technical resources. Thenational research agencies that form the Gemini partnership include:the US National Science Foundation (NSF), the UK Particle Physics andAstronomy Research Council (PPARC), the Canadian National ResearchCouncil (NRC), the Chilean Comisión Nacional de InvestigaciónCientifica y Tecnológica (CONICYT), the Australian ResearchCouncil (ARC), the Argentinean Consejo Nacional de InvestigacionesCientíficas y Técnicas (CONICET) and the Brazilian ConselhoNacional de Desenvolvimento Científico e Tecnológico (CNPq). TheObservatory is managed by the Association of Universities for Researchin Astronomy, Inc. (AURA) under a cooperative agreement with the NSF.The NSF also serves as the executive agency for the internationalpartnership.
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High-res JPEG (168kb)
High-res TIFF (2.5MB)
|This dramatic infrared image sheds new light on the early stages of the formation of giant stars in our galaxy. This image reveals remarkable details in a nebula of gas and dust expelled from AFGL 2591. This expulsion is a common feature in the formation of stars similar in size to the Sun, but it is far less common in their massive counterparts. The resolution of this image is 0.4 arcseconds.|
Low-res JPEG (15kb)
High-res JPEG (66kb)
High-res TIFF (187kb)
|This false-color image of AFGL 2591 shows some high-resolution details in the expanding outflow of gas and dust around the massive stars that are not fully visible in the color version of the image.|
Black-and-white K-band image:
Low-res JPEG (24kb)
High-res JPEG (152kb)
High-res TIFF (748kb)
|This black-and-white, K-band image of AFGL 2591 shows some fainter lobe structure and a bow shock to the left of the massive star that is not readily apparentl in the color version. This part of the expanding nebula of gas and dust around AFGL 2591 is hidden from view by a dense and extensive disk (or torus) of material encircling the star.|
A dramatic infrared image released by the Gemini Observatory (see the press release)sheds new light on the early stages of the formation of giant stars inour galaxy. This image, taken by the Gemini North telescope on MaunaKea, reveals remarkable details in a nebula of gas and dust expelledfrom AFGL 2591. AFGL 2591 is located within the Milky Way more than3,000 light-years from Earth, in the constellation Cygnus. Theresolution of these images is 0.4 arcseconds.
This striking image is part of a series of early images taken with theGemini Near Infrared Imager (NIRI) instrument during its commissioningon the Gemini North telescope. Once fully operational later this year,NIRI will be the prime near-infrared instrument on Gemini North.