Featured Research

from universities, journals, and other organizations

New 'retention model' explains enigmatic ribbon at edge of solar system

Date:
February 5, 2013
Source:
Southwest Research Institute
Summary:
Since its Oct. 2008 launch, NASA's Interstellar Boundary Explorer has provided images of the invisible interactions between our home in the galaxy and interstellar space. Particles emanating from this boundary produce a striking, narrow ribbon, which had yet to be explained despite more than a dozen possible theories. In a new "retention model," researchers suggest that charged particles trapped in this region create the ribbon as they escape as neutral atoms.

Artist’s concept of the heliosphere, showing the relationship between the Voyager spacecraft (outside the Termination Shock, faint blue shell) and the Cassini spacecraft at Saturn. The blow-up of the Saturn system shows the Cassini spacecraft, which carries the Magnetospheric Imaging Instrument (MIMI) Ion and Neutral Camera (INCA). INCA produced heliospheric images in energetic neutral atom emission from Saturn at 10 astronomical units (AU) from the sun, still deep inside the heliosphere. The Earth is at 1 AU, and the Voyagers are now beyond 100 AU. Together, the Voyagers measure the energetic particles at two discrete locations in this vast system, while Cassini/INCA provides global images of the system (from the inside). Credit:
Credit: NASA and JHU/APL

Since its October 2008 launch, NASA's Interstellar Boundary Explorer (IBEX) has provided images of the invisible interactions between our home in the galaxy and interstellar space. Particles emanating from this boundary produce a striking, narrow ribbon, which had yet to be explained despite more than a dozen possible theories. In a new "retention model," researchers from the University of New Hampshire and Southwest Research Institute suggest that charged particles trapped in this region create the ribbon as they escape as neutral atoms.

Related Articles


The Sun continually sends out a solar wind of charged particles or ions traveling in all directions at supersonic speeds. IBEX cameras measure energetic neutral atoms (ENAs) that form when charged particles become neutralized.

As solar wind ENAs leave the solar system, the majority move out in various directions, never to re-enter. However, some ENAs leave the solar system and impact other neutral atoms, becoming charges particles again. These newly formed pickup ions begin to gyrate around the local interstellar magnetic field just outside the solar system. In the regions where the magnetic field is perpendicular to their initial motion, they scatter rapidly and pile up. From those regions, some of those particles return to the solar system as secondary ENAs -- ENAs that leave the solar system and become charged and then re-neutralized, only to travel back into the solar system as ENAs a second time.

"The syrup you pour on a pancake piles up before slowly oozing out to the sides," says Dr. David McComas, IBEX principal investigator and assistant vice president of the SwRI Space Science and Engineering Division. "The secondary ENAs coming into the solar system after having been temporarily trapped in a region just outside the solar system do the same thing. As they pile up and get trapped or retained, they produce higher fluxes of ENAs from this region and form the bright ribbon seen by IBEX."

ENA energies observed in the ribbon correlate to the speed of the solar wind, which is slower (around 1 million miles per hour) at low latitudes and faster (up to 2 million miles per hour) at high latitudes.

"This was the clue that made us think the ribbon was caused by a secondary ENA source, because it so directly reflects the latitudinal structure of the solar wind," says McComas.

Simulations using a realistic solar wind structure showed remarkably good association with the IBEX data, closely reproducing the observed ribbon structure, location, and latitudinal ordering by energy. Thus far, the retention model appears best able to reproduce the IBEX observations. However, more studies are needed to confirm if variations in the solar wind affect the ribbon, as theorized.

Using information provided by this new model, future studies of the ribbon could help determine the properties of the nearby galactic magnetic field, opening a window into the physics of the nearby galactic medium. In addition, the IBEX ribbon could provide researchers with a means for measuring the strength of the interstellar magnetic field, as well as its direction.

The paper, "Spatial Retention of Ions Producing the IBEX Ribbon," by N.A. Schwadron and D.J. McComas was published Feb. 4 in the Astrophysical Journal. The IBEX team's papers on the first six models about the ribbon's origin were published in Science (2009).

IBEX is the latest in NASA's series of low-cost, rapidly developed Small Explorer space missions. Southwest Research Institute in San Antonio leads the IBEX mission with a team of national and international partners. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Explorers Program for NASA's Science Mission Directorate in Washington.


Story Source:

The above story is based on materials provided by Southwest Research Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. N. A. Schwadron, D. J. McComas. Spatial Retention of Ions Producing The IBEX ribbon. The Astrophysical Journal, 2013; 764 (1): 92 DOI: 10.1088/0004-637X/764/1/92

Cite This Page:

Southwest Research Institute. "New 'retention model' explains enigmatic ribbon at edge of solar system." ScienceDaily. ScienceDaily, 5 February 2013. <www.sciencedaily.com/releases/2013/02/130205102155.htm>.
Southwest Research Institute. (2013, February 5). New 'retention model' explains enigmatic ribbon at edge of solar system. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2013/02/130205102155.htm
Southwest Research Institute. "New 'retention model' explains enigmatic ribbon at edge of solar system." ScienceDaily. www.sciencedaily.com/releases/2013/02/130205102155.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Space & Time News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Scientists Find Invisible Space Shield Protecting Earth

Scientists Find Invisible Space Shield Protecting Earth

Newsy (Nov. 27, 2014) An invisible barrier is keeping dangerous super fast electrons from interfering with our atmosphere, but scientists aren't entirely sure how. Video provided by Newsy
Powered by NewsLook.com
NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Feast Your Eyes: Lamb Chop Sent Into Space from UK

Feast Your Eyes: Lamb Chop Sent Into Space from UK

Reuters - Light News Video Online (Nov. 25, 2014) Take a stab at this -- stunt video shows a lamb chop's journey from an east London restaurant over 30 kilometers into space. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Soyuz Spacecraft Docks With International Space Station: NASA

Soyuz Spacecraft Docks With International Space Station: NASA

AFP (Nov. 24, 2014) A Russian Soyuz spacecraft carrying Italy's first female astronaut safely docks with the International Space Station, according to NASA. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Enigmatic 'ribbon' Of Energy Discovered by NASA Satellite Explained

Feb. 5, 2013 After three years of puzzling over a striking "ribbon" of energy and particles discovered by NASA's Interstellar Boundary Explorer at the edge of our solar system, scientists may be on ... read more

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins