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The Omega Nebula: Hotbed of Star Formation
A watercolor fantasyland? No. It's actually an image of the center of the Omega Nebula, a hotbed of newly born stars wrapped in colorful blankets of glowing gas and cradled in an enormous cold, dark hydrogen cloud. This stunning picture was taken by the newly installed Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope.
The region of the nebula shown in this photograph is about 3,500 times wider than our solar system. The area represents about 60 percent of the total view captured by ACS. The nebula, also called M17 and the Swan Nebula, resides 5,500 light-years away in the constellation Sagittarius.
Like its famous cousin in Orion, the Swan Nebula is illuminated by ultraviolet radiation from young, massive stars, located just beyond the upper right corner of the image. Each star is about six times hotter and 30 times more massive than the Sun. The powerful radiation from these stars evaporates and erodes the dense cloud of cold gas within which the stars formed. The blistered walls of the hollow cloud shine primarily in the blue, green, and red light emitted by excited atoms of hydrogen, nitrogen, oxygen, and sulfur. Particularly striking is the rose-like feature, seen to the right of center, which glows in the red light emitted by hydrogen and sulfur.
As the infant stars evaporate the surrounding cloud, they expose dense pockets of gas that may contain developing stars. Because these dense pockets are more resistant to the withering radiation than the surrounding cloud, they appear as sculptures in the walls of the cloud or as isolated islands in a sea of glowing gas. One isolated pocket is seen at the center of the brightest region of the nebula and is about 10 times larger than our solar system. Other dense pockets of gas have formed the remarkable feature jutting inward from the left edge of the image, which resembles the famous Horsehead Nebula in Orion.
ACS made this observation on April 1 and 2, 2002. The color image is constructed from four separate images taken in these filters: blue, near infrared, hydrogen alpha, and doubly ionized oxygen.
About the Object
- R.A. PositionR.A. PositionRight ascension – analogous to longitude – is one component of an object's position.18h 20m 25.99s
- Dec. PositionDec. PositionDeclination – analogous to latitude – is one component of an object's position.18h 20m 25.99s
- ConstellationConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.Sagittarius
- DistanceDistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.About 5,500 light-years (1690 parsecs)
- DimensionsDimensionsThe physical size of the object or the apparent angle it subtends on the sky.The image is roughly 2.5 arcminutes (4.1 light-years or 1.3 parsecs) across.
About the Data
- Data DescriptionData DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.Principal Astronomers: NASA and the ACS Science Team (H. Ford, G. Illingworth, M. Clampin, G. Hartig, T. Allen, K. Anderson, F. Bartko, N. Benitez, J. Blakeslee, R. Bouwens, T. Broadhurst, R. Brown, C. Burrows, . Campbell, E. Cheng, N. Cross, P. Feldman, M. Franx, D. Golimowski, C. Gronwall, R. Kimble, J. Krist, M. Lesser, D. Magee, A. Martel, W. J. McCann, G. Meurer, G. Miley, M. Postman, P. Rosati, M. Sirianni, W. Sparks, P. Sullivan, H. Tran, Z. Tsvetanov, R. White, and R. Woodruff) - InstrumentInstrumentThe science instrument used to produce the data.HST>ACS/WFC
- Exposure DatesExposure DatesThe date(s) that the telescope made its observations and the total exposure time.April 1 - 2, 2002, Exposure Time: 2.6 hours
- FiltersFiltersThe camera filters that were used in the science observations.F435W (B), F502N ([O III]), F658N (H-alpha), F814W (I)
- Object NameObject NameA name or catalog number that astronomers use to identify an astronomical object.M17, NGC 6618, Swan Nebula, Omega Nebula
- Object DescriptionObject DescriptionThe type of astronomical object.Gaseous Nebula in the Milky Way Galaxy
- Release DateApril 30, 2002
- Science ReleaseHubble’s New Camera Delivers Breathtaking Views of the Universe
- CreditsNASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA; The ACS Science Team: H. Ford, G. Illingworth, M. Clampin, G. Hartig, T. Allen, K. Anderson, F. Bartko, N. Benitez, J. Blakeslee, R. Bouwens, T. Broadhurst, R. Brown, C. Burrows, D. Campbell, E. Cheng, N. Cross, P. Feldman, M. Franx, D. Golimowski, C. Gronwall, R. Kimble, J. Krist, M. Lesser, D. Magee, A. Martel, W. J. McCann, G. Meurer, G. Miley, M. Postman, P. Rosati, M. Sirianni, W. Sparks, P. Sullivan, H. Tran, Z. Tsvetanov, R. White, and R. Woodruff.

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Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov