1000 Days of Infrared Wonders
IRAC not only probes what is known - it also has uncovered some mysterious objects like this so-called "tornado" nebula.
Because the camera is sensitive to light emitted from shocked molecular hydrogen (seen here in green), astronomers think
that this strange beast is the result of an outflowing jet of material from a young star that has generated shock waves in
surrounding gas and dust.
Credit: NASA / JPL-Caltech / J. Bally (University of Colorado)
April 16, 2012
Cambridge, MA - For the last 1000 days the Infrared Array Camera (IRAC), aboard NASA's Spitzer Space Telescope,
has been operating
continuously to probe the universe from its most distant regions to our local solar neighborhood. The IRAC "warm" program began
once Spitzer used up its liquid helium coolant, thus completing its "cold" mission. To commemorate 1000 days of infrared wonders,
the program is releasing a gallery of the 10 best IRAC images.
"IRAC continues to be an amazing camera, still producing important discoveries and spectacular new images of
the infrared universe," said principal investigator Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics.
The warm-mission images particularly highlight the continuing capabilities of Spitzer. Indeed, NASA's Senior Review Panel
has recommended extending the Spitzer warm mission through 2015. They specifically commended the Spitzer team for telescope
improvements that have made it a powerful instrument for science, especially in exoplanet studies.
IRAC is sensitive to infrared light - light beyond the red end of the visible spectrum. It can image nebulae of cold dust,
peer inside obscured dust clouds where new stars are forming, and detect faint emissions from very distant galaxies.
After a long life of hydrogen-burning nuclear fusion, stars move into later life states whose details depend on their masses.
This IRAC image of the Helix Nebula barely spots the star itself at the center, but clearly shows how the aging star has
ejected material into space around it, creating a "planetary nebula." The Helix Nebula is located 650 light-years away in
the constellation Aquarius. This image was taken during Spitzer's warm mission.
Credit: NASA / JPL-Caltech / J. Hora (CfA) & W. Latter (NASA/Herschel)
During its 1000-day undertaking, IRAC used its two shortest-wavelength infrared sensors. However, some of the images
featured today include data collected during the cold mission, when all four of its infrared sensors could function.
The top 10 IRAC images the team selected are:
• A "space tornado"
• The Orion Nebula
• The Helix Nebula
• The Trifid Nebula
• The "Mountains of Creation"
• A young star cluster
• Our Milky Way galaxy
• The Whirlpool galaxy
• The Sombrero galaxy
• The young, distant universe
The early universe contained only hydrogen and helium. No other chemical elements existed. All of the elements needed
for life were created later in the nuclear furnaces of stars, and then ejected into space. IRAC studies how stars mature.
It can observe how the processes of stellar evolution affect the environment. The Trifid Nebula hosts stars at all stages
of life, surrounded by gas and dust that form a beautiful roseate nebula. It's located 5,400 light-years away in the
Credit: NASA / JPL-Caltech
Many additional images from Spitzer can be found online at
Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration
between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized
into six research divisions, study the origin, evolution and ultimate fate of the universe.
Within galaxies like the Milky Way, giant clouds of gas and dust coalesce under the influence of gravity until new stars
are born. IRAC can both measure the warm dust and peer deeply into it to study the processes at work. In this giant cloud
several stellar nurseries can be seen, some still within the tips of dusty "mountains of creation." This image shows the
eastern edge of a region known as W5, near the Perseus constellation 7,000 light-years away.
Credit: NASA / JPL-Caltech / CfA
After blowing away its natal material, the young star cluster seen here emits winds and harsh ultraviolet light that
sculpt the remnant cloud into fantastic shapes. Astronomers are not sure when that activity suppresses future star
formation by disruption, and when it facilitates star formation through compression. The cluster, known as DR22,
is in the constellation Cygnus the Swan. This image was taken during Spitzer's warm mission.
Credit: NASA / JPL-Caltech
Star formation helps shape a galaxy's structure through shock waves, stellar winds, and ultraviolet radiation.
In this image of the nearby Sombrero Galaxy, IRAC clearly sees a dramatic disk of warm dust (red) caused by star formation
around the central bulge (blue). The Sombrero is located 28 million light-years away in the constellation Virgo.
Credit: NASA / JPL-Caltech / R. Kennicutt (Univ. of Arizona)
The famous nebula in Orion, located about 1,340 light-years from Earth, is actively making new stars today.
Although the optical nebula is dominated by the light from four massive, hot young stars, IRAC reveals many other
young stars still embedded in their dusty womb. It also finds a long filament of star-forming activity containing
thousands of young protostars. Some of these stars may host still-forming planets. This image was taken during Spitzer's
Credit: NASA / JPL-Caltech / Univ. of Toledo