Chandra Records Local Cosmic Event

Solar Flare
Full disk H-Alpha image of the Sun Holloman AFB, New Mexico
Image: Space Environment Center
August 4, 1999 :: One of Chandra's sensitive X-ray cameras detected x-rays from a cosmic event even before the door to the observatory has been opened. A solar flare occurred on the afternoon of August 2, and at 5:25 p.m. EDT the High Resolution Camera (HRC) aboard Chandra recorded an increase in the count rate. After checking the space weather web page, scientists found that at 5:18 p.m.EDT, the Geostationary Operational Environmental Satellite (GOES) had detected soft X-rays from the flare.

Recent Headlines
During the check-out phase of the observatory, the HRC door has been opened and power to the instrument has been turned on so that scientists can assess the operation of the camera.

"The HRC team members were excited when they realized they had detected a real event," said Steve Murray, the Principal Investigator of the HRC. The flare was also detected by the Electron-Proton Helium Instrument (EPHIN) on Chandra, which monitors the concentration of energetic charged particles in the space through which Chandra travels.

X-ray Image of Our Sun
X-ray image of our sun, courtesy of The Soft X-ray Telescope on board the Yohkoh satellite.
The Chandra X-ray Observatory will not study X-rays from the Sun because it is too bright. Chandra's exceptional mirrors and sensitive instruments are designed to measure and image faint cosmic x-ray sources, from comets to quasars at the edge of the known universe. The HRC detection of the solar flare amounts to background radiation that will be subtracted when the telescope is observing targets. Other space telescopes have been built specifically to study solar X-rays.

The August 2, flare was a major solar flare. Flares such as this can gradually damage Chandra's solar panels and some components of the X-ray cameras. This damage is taken into account when the lifetime of the observatory is calculated. Chandra is expected to operate for 5 years, with a possible lifetime of 10 to 15 years.
Labelled sketch of the CXO

Chandra schematic

(Illustration: CXC/NGST)


Return to Chandra Chronicles

Highlights and Feature Stories from the Chandra Project
Archived reports of past Chandra Chronicles
Receive the Chandra Digest
Updated: March 27, 2008