Dwarf Galaxy Holmberg IX

Esahubble_heic0801g_1024

esahubble_heic0801g January 8th, 2008

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgment: D. de Mello (Catholic University of America and GSFC)

This loose collection of stars is actually a dwarf irregular galaxy, called Holmberg IX. It resides just off the outer edge of M81, a large spiral galaxy in Ursa Major. This image was taken with Hubble's Advanced Camera for Surveys in early 2006. Holmberg IX is of the so-called Magellanic type of galaxy, as its size and irregularity in structure are similar to the Small Magellanic Cloud, a neighbour to our own Milky Way. Holmberg IX was first discovered by astronomer Sidney van den Bergh in 1959, and catalogued as DDO 66. The galaxy received its "Holmberg IX" naming when it was discussed in Eric Holmberg's study of groups of galaxies ten years later. It is suspected that the dwarf galaxy was created as a result of a galactic interaction between M81 and neighbouring galaxy M82. Of the more than 20,000 stars that can be resolved in this Hubble image, only about 10% are considered to be old stars with ages of billions of years. The rest are thought to be young stars with ages of only 10 - 200 million years. Due to the Advanced Camera for Surveys' resolution in this image, astronomers have noted that the old and the young stars have distinct spatial distributions which might be related to their origin. Simulations predict that the triplet M81, M82, and nearby NGC 3077 had a close passage 200-300 million years ago. This close encounter may have triggered the newer star formation that has occurred in Holmberg IX. The bluish-white fuzz in the space surrounding M81 and Holmberg IX is new star formation triggered by gravitational interactions between the two galaxies. There are many low mass galaxies that form stars in nearby space. While none of these are as dominated by recently produced stars as Holmberg IX, they might be related to the same family. By understanding how Holmberg IX was formed, scientists hope to understand their role as building blocks of large galaxies.

Provider: Hubble Space Telescope | ESA

Image Source: https://www.spacetelescope.org/images/heic0801g/

Curator: ESA/Hubble, Garching bei München, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
Holmberg IX M81 M82
Subject - Local Universe
Galaxy > Type > Interacting
Galaxy > Size > Dwarf
Esahubble_heic0801g_128
 

Position Details

Position (ICRS)
RA = 9h 57m 30.6s
DEC = 69° 2’ 59.2”
Orientation
North is 145.4° CW
Field of View
3.1 x 3.3 arcminutes
Constellation
Ursa Major

Color Mapping

  Telescope Spectral Band Wavelength
Orange Hubble (ACS) Infrared (I) 814.0 nm
Cyan Hubble (ACS) Optical (V) 555.0 nm
Spectrum_base
Orange
Cyan
Esahubble_heic0801g_1280
×
ID
heic0801g
Subject Category
C.5.1.7   C.5.2.2  
Subject Name
Holmberg IX, M81, M82
Credits
NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgment: D. de Mello (Catholic University of America and GSFC)
Release Date
2008-01-08T20:00:00
Lightyears
Redshift
Reference Url
https://www.spacetelescope.org/images/heic0801g/
Type
Observation
Image Quality
Distance Notes
Facility
Hubble Space Telescope, Hubble Space Telescope
Instrument
ACS, ACS
Color Assignment
Orange, Cyan
Band
Infrared, Optical
Bandpass
I, V
Central Wavelength
814, 555
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
149.377365419, 69.0497904959
Reference Dimension
3779.0, 3993.0
Reference Pixel
1889.5, 1996.5
Scale
-1.38777353311e-05, 1.38777353311e-05
Rotation
-145.40000000000012
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
ESA/Hubble
URL
http://www.spacetelescope.org/
Name
Email
Telephone
Address
Karl-Schwarzschild-Strasse 2
City
Garching bei München
State/Province
Postal Code
D-85748
Country
Germany
Rights
Creative Commons Attribution 4.0 International License
Publisher
ESA/Hubble
Publisher ID
esahubble
Resource ID
heic0801g
Metadata Date
2007-12-13T15:25:04-05:00
Metadata Version
1.0
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Detailed color mapping information coming soon...

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There is no distance meta data in this image.

 

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