The two mysterious populations of NGC 2419

Esahubble_potw1908a_1024

esahubble_potw1908a February 25th, 2019

Credit: ESA/Hubble & NASA, S. Larsen et al.

Globular clusters like NGC 2419, visible in this image taken with the NASA/ESA Hubble Space Telescope, are not only beautiful, but also fascinating. They are spherical groups of stars which orbit the centre of a galaxy; in the case of NGC 2419, that galaxy is the Milky Way. NGC 2419 can be found around 300000 light-years from the Solar System, in the constellation Lynx (the Lynx). The stars populating globular clusters are very similar to one another, with similar properties such as metallicity. The similarity of these stellar doppelgngers is due to their formation early in the history of the galaxy. As the stars in a globular cluster all formed at around the same time, they tend to display reasonably homogeneous properties. It was believed that this similarity also extended to the stellar helium content; that is, it was thought that all stars in a globular cluster would contain comparable amounts of helium. However, Hubbles observations of NGC 2419 have shown that this is not always the case. This surprising globular cluster turns out to be made up of two separate populations of red giant stars, one of which is unusually helium-rich. Other elements within the different stars in NGC 2419 vary too nitrogen in particular. On top of this, these helium-rich stars were found to be predominantly in the centre of the globular cluster, and to be rotating. These observations have raised questions about the formation of globular clusters; did these two drastically different groups of stars form together? Or did this globular cluster come into being by a different route entirely?

Provider: Hubble Space Telescope | ESA

Image Source: https://www.spacetelescope.org/images/potw1908a/

Curator: ESA/Hubble, Garching bei München, None, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
NGC 2419
Subject - Local Universe
Star > Grouping > Cluster > Globular
Esahubble_potw1908a_128
 

Position Details

Position (ICRS)
RA = 7h 38m 8.8s
DEC = 38° 52’ 43.0”
Orientation
North is 46.4° CCW
Field of View
2.6 x 2.6 arcminutes
Constellation
Lynx

Color Mapping

  Telescope Spectral Band Wavelength
Arrow_left_red Hubble Space Telescope (WFC3) Optical (I) 814.0 nm
Arrow_left_green Hubble Space Telescope (WFC3) Optical (V) 555.0 nm
Arrow_left_blue Hubble Space Telescope (WFC3) Optical (B) 438.0 nm
Spectrum_base
Arrow_top_red
Arrow_top_green
Arrow_top_blue
Esahubble_potw1908a_1280
×
ID
potw1908a
Subject Category
C.3.6.4.2  
Subject Name
NGC 2419
Credits
ESA/Hubble & NASA, S. Larsen et al.
Release Date
2019-02-25T06:00:00
Lightyears
Redshift
Reference Url
https://www.spacetelescope.org/images/potw1908a/
Type
Observation
Image Quality
Distance Notes
Facility
Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope
Instrument
WFC3, WFC3, WFC3
Color Assignment
Red, Green, Blue
Band
Optical, Optical, Optical
Bandpass
I, V, B
Central Wavelength
814, 555, 438
Start Time
Integration Time
Dataset ID
None, None, None
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
114.536509559, 38.8786131603
Reference Dimension
3916.0, 3892.0
Reference Pixel
1958.0, 1946.0
Scale
-1.10060278079e-05, 1.10060278079e-05
Rotation
46.419999999999909
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
None
Postal Code
D-85748
Country
Germany
Rights
Creative Commons Attribution 4.0 International License
Publisher
ESA/Hubble
Publisher ID
esahubble
Resource ID
potw1908a
Metadata Date
2018-12-31T16:59:04+01:00
Metadata Version
1.1
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Detailed color mapping information coming soon...

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There is no distance meta data in this image.