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: SDO captures images of two mid-level flares

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

SDO captures images of two mid-level flares

Dec 19, 2014

The sun emitted a mid-level flare on Dec. 18, 2014, at 4:58 p.m. EST. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts ...

Why is Venus so horrible?

Dec 19, 2014

Venus sucks. Seriously, it's the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you ...

Image: Christmas wrapping the Sentinel-3A antenna

Dec 19, 2014

The moment a team of technicians, gowned like hospital surgeons, wraps the Sentinel-3A radar altimeter in multilayer insulation to protect it from the temperature extremes found in Earth orbit.

Video: Flying over Becquerel

Dec 19, 2014

This latest release from the camera on ESA's Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.

Spinning up a dust devil on Mars

Dec 19, 2014

Spinning up a dust devil in the thin air of Mars requires a stronger updraft than is needed to create a similar vortex on Earth, according to research at The University of Alabama in Huntsville (UAH).

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.