Spectrum of stars in NGC 6822 and the Milky Way galaxy

Eso_eso9920c_1024

eso_eso9920c February 27th, 1999

Credit: ESO

This chart displays a FORS1 spectrum of a blue supergiant in NGC 6822 (in the middle), as compared with those of supergiant stars (upper and lower) of similar atmospheric temperature in the Milky Way Galaxy. The observations were carried out by the FORS Commissioning Team on October 1, 1998, using the Multiple Object Spectroscopy (MOS) mode of FORS1. A total of 11 stars in NGC 6822 were observed simultaneously with an exposure time of 30 min. The visual magnitude of supergiant star centered on slit no. 5 is V = 18.11 and the spectral type is in the interval O9.5Ia - B0Ia. It is apparent from the figures that many spectral lines in the supergiant star in NGC 6822 are much weaker than in the Milky Way counterparts.This confirms the earlier finding that NGC 6822 has a different chemical composition - a lower content of heavy elements (or "metallicity") - than what is observed in our Galaxy.

Provider: European Southern Observatory

Image Source: https://www.eso.org/public/images/eso9920c/

Curator: European Southern Observatory, Garching bei München, Germany

Image Use Policy: Creative Commons Attribution 4.0 International License

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Image Details

Image Type
Observation
Object Name
Milky Way NGC 6822 Spectrum
Subject - Milky Way
Galaxy
Galaxy

Color Mapping

  Telescope Spectral Band Wavelength
Pseudocolor VLT (FORS1) Optical -
Eso_eso9920c_1280
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ID
eso9920c
Subject Category
B.5   C.5  
Subject Name
Milky Way, NGC 6822, Spectrum
Credits
ESO
Release Date
1999-02-27T00:00:00
Lightyears
Redshift
Reference Url
https://www.eso.org/public/images/eso9920c/
Type
Observation
Image Quality
Distance Notes
Facility
Very Large Telescope
Instrument
FORS1
Color Assignment
Pseudocolor
Band
Optical
Bandpass
Central Wavelength
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
Equinox
Reference Value
Reference Dimension
3000.0, 2156.0
Reference Pixel
Scale
Rotation
Coordinate System Projection:
Quality
FITS Header
Notes
Creator (Curator)
European Southern Observatory
URL
http://www.eso.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
European Southern Observatory
Publisher ID
eso
Resource ID
eso9920c
Metadata Date
2010-03-01T11:06:47+01:00
Metadata Version
1.1
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Detailed color mapping information coming soon...

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