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Spitzer Studies a Stellar Playground With a Long History This image from NASA's Spitzer Space Telescope shows the
Perseus Molecular Cloud, a massive collection of gas and dust that stretches
over 500 light-years across. Home to an abundance of young stars, it has drawn
the attention of astronomers for decades.
Spitzer's Multiband Imaging Photometer (MIPS) instrument
took this image during Spitzer's "cold
mission," which ran from the spacecraft's launch in 2003
until 2009, when the space telescope exhausted its supply of liquid helium
coolant. (This marked the beginning of Spitzer's "warm mission.") Infrared
light can't be seen by the human eye, but warm objects, from human bodies to
interstellar dust clouds, emit infrared light.
Infrared radiation from warm dust generates much of the
glow seen here from the Perseus Molecular Cloud. Clusters of stars, such as the
bright spot near the left side of the image, generate even more infrared light
and illuminate the surrounding clouds like the Sun lighting up a cloudy sky at
sunset. Much of the dust seen here emits little to no visible light (in fact,
the dust blocks visible light) and is therefore revealed most clearly with
infrared observatories like Spitzer.
On
the right side of the image is a bright clump of young stars known as NGC 1333,
which Spitzer has observed
multiple times.
It is located about 1,000 light-years from Earth. That sounds far, but it is
close compared to the size of our galaxy, which is about 100,000 light-years
across. NGC 1333's proximity and strong infrared emissions made it visible to astronomers
using some of the earliest infrared instruments.
This image from NASA'S Spitzer Space Telescope shows the location and apparent size of the Perseus Molecular Cloud in the night sky. Located on the edge of the Perseus Constellation, the collection of gas and dust is about 1,000 light-years from Earth and about 500 light-years wide.
Credit: NASA/JPL-Caltech
Full image and caption
In
fact, some of its stars were first observed in the mid-1980s with the Infrared
Astronomical Survey (IRAS), a joint mission between NASA, the United Kingdom
and the Netherlands. The first infrared satellite telescope, it observed the
sky in infrared wavelengths blocked by Earth's atmosphere, providing the
first-ever view of the universe in those wavelengths.
More than 1,200 peer-reviewed research papers have been
written about NGC 1333, and it has been studied in other wavelengths of light,
including by the Hubble
Space Telescope, which detects mostly visible light, and the Chandra
X-Ray Observatory.
Many young stars in the cluster are sending massive
outflows of material - the same material that forms the star - into space. As
the material is ejected, it is heated up and smashes into the surrounding
interstellar medium. These factors cause the jets to radiate brightly, and they
can be seen in close-up studies of the region. This has provided astronomers
with a clear glimpse of how stars go from a sometimes-turbulent adolescence
into calmer adulthood.
An
Evolving Mystery
Other clusters of stars seen below NGC 1333 in this image have
posed a fascinating mystery for astronomers: They appear to contain stellar
infants, adolescents and adults. Such a closely packed mixture of ages is
extremely odd, according to Luisa Rebull, an astrophysicist at NASA's Infrared
Science Archive at Caltech-IPAC who has studied NGC 1333 and some of the
clusters below it. Although many stellar siblings may form together in tight
clusters, stars are always moving, and as they grow older they tend to move farther
and farther apart.
This annotated image of the Perseus Molecular Cloud, provided by NASA's Spitzer Space Telescope, shows the location of various star clusters, including NGC 1333.
Credit: NASA/JPL-Caltech
Full image and caption
Finding such a closely packed mixture of apparent ages
doesn't fit with current ideas about how stars evolve. "This region is
telling astronomers that there's something we don't understand about star
formation," said Rebull. The puzzle presented by this region is one thing
that keeps astronomers coming back to it. "It's one of my favorite regions
to study," she added.
Since IRAS's early observations, the region has come into
clearer focus, a process that is common in astronomy, said Rebull. New
instruments bring more sensitivity and new techniques, and the story becomes
clearer with each new generation of observatories. On Jan. 30, 2020, NASA will
decommission the Spitzer Space Telescope, but its legacy has paved the way for
upcoming observatories, including the James Webb Space Telescope,
which will also observe infrared light.
The Spitzer-MIPS data used for this image is at the
infrared wavelength of 24 microns. Small
gaps along the edges of this image not observed by Spitzer were filled in using
22-micron data from NASA's Wide-Field Infrared Survey Explorer (WISE).
To learn more
about Spitzer and how it studies the infrared universe, check out the Spitzer
360 VR experience, now available on the NASA Spitzer channel on YouTube: https://youtu.be/kyXqRD_z8c0.
More
information about Spitzer is available at the following site(s):
https://www.nasa.gov/mission_pages/spitzer/main
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