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Zeta Orionis:
Chandra Observes That Massive Stars Are More Sun-Like Than Believed
This figure is a composite of the
X-ray spectrum and CCD image of Zeta Orionis.
The Advanced CCD Imaging Spectrometer (ACIS) image
(upper right) clearly shows that Zeta Orionis is a
binary, or, double, star system. The recent results by
Waldron and Cassinelli focused on the larger "A"
component of the system. The spatial resolution between
the "A" and "B" elements of Zeta Orionis are a mere 2.4
arcseconds away from one another, demonstrating the
fantastic resolution capable by the Chandra X-ray
Observatory. The color contours in the image are scaled
logarithmically in relationship to their X-ray
intensities.
The X-ray emission line spectrum (lower left)
represents the Chandra High-Energy Transmission Grating
Medium Energy Grating observation of Zeta Orionis "A".
By determining the wavelength associated with each
emission line, scientists can identify the atomic
species and their states of ionization, which can be
used to determine the temperature range of the plasma.
Furthermore, by measuring the relative line strengths
of certain ions, scientists can extract densities and
specific temperatures of the X-ray emitting plasma. One
major difference between this O-star spectrum and that
of other stars such as the Sun is that the X-ray
emission lines are significantly broader, indicating a
larger dispersion in plasma velocities.
| Fast Facts for Zeta Orionis: |
| Credit |
NASA/EIT/W.Waldron, J.Cassinelli |
| Scale |
Image is 27 arcsec on a side. |
| Category |
Normal Stars & Star Clusters |
| Coordinates (J2000) |
RA 05h 40m 45.50s | Dec -01° 56' 34" |
| Constellation |
Orion |
| Observation Dates |
April 8, 2000
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| Observation Time |
17 hours |
| Color Code |
Intensity |
| Instrument |
ACIS |
| Release Date |
October 18, 2000 |
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