Four Famous Nebulae

Spitzer_ssc2021-07c_1024

spitzer_ssc2021-07c August 17th, 2021

Credit: NASA/JPL-Caltech

These four nebulae (star-forming clouds of gas and dust) are known for their breathtaking beauty: the Eagle Nebula (which contains the Pillars of Creation), the Omega Nebula, the Trifid Nebula, and the Lagoon Nebula. In the 1950s, a team of astronomers made rough distance measurements to some of the stars in these nebulae and were able to infer the existence of the Sagittarius Arm. Their work provided some of the first evidence of our galaxy's spiral structure. In a new study, astronomers have shown that these nebulae are part of a substructure within the arm that is angled differently from the rest of the arm.

A key property of spiral arms is how tightly they wind around a galaxy. This characteristic is measured by the arm's pitch angle. A circle has a pitch angle of 0 degrees, and as the spiral becomes more open, the pitch angle increases. Most models of the Milky Way suggest that the Sagittarius Arm forms a spiral that has a pitch angle of about 12 degrees, but the protruding structure has a pitch angle of nearly 60 degrees.

Similar structures – sometimes called spurs or feathers – are commonly found jutting out of the arms of other spiral galaxies. For decades scientists have wondered whether our Milky Way's spiral arms are also dotted with these structures or if they are relatively smooth.

Provider: Spitzer Space Telescope

Image Source: https://www.spitzer.caltech.edu/image/ssc2021-07c-four-famous-nebulae

Curator: Spitzer Space Telescope, Pasadena, CA, USA

Image Use Policy: https://www.spitzer.caltech.edu/page/image-use-policy

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Image Details

Image Type
Collage
Object Name
Eagle Nebula Omega Nebula Trifid Nebula Lagoon Nebula
Subject - Milky Way
Nebula > Type > Star Formation

Color Mapping

  Telescope Spectral Band Wavelength
Blue Spitzer (IRAC) Infrared (Near-IR) 3.6 µm
Green Spitzer (IRAC) Infrared (Near-IR) 4.5 µm
Red Spitzer (IRAC) Infrared (Mid-IR) 8.0 µm
Spectrum_base
Blue
Green
Red
Spitzer_ssc2021-07c_1280
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ID
ssc2021-07c
Subject Category
B.4.1.2.  
Subject Name
Eagle Nebula, Omega Nebula, Trifid Nebula, Lagoon Nebula
Credits
NASA/JPL-Caltech
Release Date
2021-08-17
Lightyears
Redshift
Reference Url
https://www.spitzer.caltech.edu/image/ssc2021-07c-four-famous-nebulae
Type
Collage
Image Quality
Good
Distance Notes
Facility
Spitzer, Spitzer, Spitzer
Instrument
IRAC, IRAC, IRAC
Color Assignment
Blue, Green, Red
Band
Infrared, Infrared, Infrared
Bandpass
Near-IR, Near-IR, Mid-IR
Central Wavelength
3600, 4500, 8000
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
Equinox
Reference Value
Reference Dimension
Reference Pixel
Scale
Rotation
Coordinate System Projection:
Quality
FITS Header
Notes
Creator (Curator)
Spitzer Space Telescope
URL
http://www.spitzer.caltech.edu
Name
Email
Telephone
Address
1200 E. California Blvd.
City
Pasadena
State/Province
CA
Postal Code
91125
Country
USA
Rights
https://www.spitzer.caltech.edu/page/image-use-policy
Publisher
Spitzer Science Center
Publisher ID
spitzer
Resource ID
Metadata Date
2021-08-20T18:53:26Z
Metadata Version
1.2
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Detailed color mapping information coming soon...

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There is no distance meta data in this image.