SECCHI team obtains images of the solar wind at Earth

Dec 07, 2007

Using the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instruments on board NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft, a consortium of scientists has seen, for the first time, large waves of solar material sweeping past Earth.

The SECCHI team has obtained images of the density enhancements whose prior existence was known only from point measurements by in situ spacecraft. The team’s results will be discussed during an invited talk by Dr. Neil Sheeley of the Naval Research Laboratory (NRL) at the fall meeting of the American Geophysical Union in San Francisco, CA, in December. The scientific paper is scheduled for publication in the March 1, 2008 issue of the Astrophysical Journal.

During relatively quiet solar conditions throughout the spring and summer of 2007, the SECCHI Heliospheric Imager HI-2 telescope on the STEREO B solar-orbiting spacecraft observed a succession of wavefronts sweeping past Earth. The scientists have compared these white-light images with in situ plasma and magnetic feld measurements obtained by near-Earth spacecraft, and found a perfect association between the occurrence of these waves and the arrival of high-density regions that rotate with the Sun. These compression regions are believed to form as high-speed wind from dark areas of the solar corona known as coronal holes run into the low-speed wind in front of it.

Currently, the researchers are tracking HI-2 waves backward toward the Sun to see exactly how they originate. Preliminary results suggest that the waves begin as blobs of material that are shed continuously from coronal streamers.

The STEREO twin spacecraft were launched on October 25, 2006 with the objective of obtaining stereoscopic observations of the Sun from a near-Earth orbit. After some initial maneuvers, which included a gravitational assist from the moon, the two spacecraft achieved their orbits with one spacecraft (A) located slightly closer to the Sun and gradually moving ahead of Earth and the other spacecraft (B) located slightly farther from the Sun and gradually falling behind. The angular distance between the A and B spacecraft increases at a rate of approximately 45 degrees per year and was about 26 degrees in early September 2007.

Each spacecraft is equipped with a suite of Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instruments. In addition to an extreme ultraviolet imager (EUVI), there are two coronagraphs (COR1 and COR2) and two heliospheric imagers (HI-1 and HI-2) pointing 13 degrees and 53 degrees off to the side.

Source: Naval Research Laboratory

Explore further: Bad weather delays Japan asteroid probe lift off

add to favorites email to friend print save as pdf

Related Stories

Scientists 'see' flux rope formation for the first time

Apr 03, 2013

(Phys.org) —Naval Research Laboratory scientists have observed, for the very first time, the formation of solar flux ropes, which are a type of solar magnetic field. Models of flux ropes have been drawn ...

NASA’s STEREO spots a new nova

May 01, 2012

While on duty observing the Sun from its position in solar orbit, NASA’s STEREO-B spacecraft captured the sudden appearance of a distant bright object. This flare-up turned out to be a nova — designated ...

STEREO sees complete far side of the Sun

Jun 14, 2011

(PhysOrg.com) -- The far side unveiled! This is the first complete image of the solar far side, the half of the sun invisible from Earth. Captured on June 1, 2011, the composite image was assembled from NASA's ...

STEREO Reveals the Anatomy of a Solar Storm in 3D

Apr 28, 2009

(PhysOrg.com) -- Observations from NASA's twin Solar Terrestrial Relations Observatory (STEREO) spacecraft have allowed scientists to reveal for the first time the speed, trajectory, and three-dimensional shape of solar explosions ...

Recommended for you

Bad weather delays Japan asteroid probe lift off

2 hours ago

Bad weather will delay the launch of a Japanese space probe on a six-year mission to mine a distant asteroid, just weeks after a European spacecraft's historic landing on a comet captivated the world.

Manchester scientists boost NASA's missions to Mars

11 hours ago

Computer Scientists from The University of Manchester have boosted NASA space missions by pioneering a global project to develop programs that efficiently test and control NASA spacecraft.

ESA image: The gold standard

11 hours ago

The Eutelsat-9B satellite with its EDRS-A payload is shown in the anechoic test chamber of Airbus Defence and Space in Toulouse, France, having completed its final antenna pattern tests today.

Frost-covered chaos on Mars

11 hours ago

Thanks to a break in the dusty 'weather' over the giant Hellas Basin at the beginning of this year, ESA's Mars Express was able to look down into the seven kilometre-deep basin and onto the frosty surface ...

Rosetta's comet: In the shadow of the coma

18 hours ago

This NAVCAM mosaic comprises four individual images taken on 20 November from a distance of 30.8 km from the centre of Comet 67P/C-G. The image resolution is 2.6 m/pixel, so each original 1024 x 1024 pixel ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

earls
not rated yet Dec 07, 2007
Nice. I'd like to see their images.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.