Featured Research

from universities, journals, and other organizations

Mercury’s comet-like appearance spotted by satellites looking at the Sun

Date:
September 23, 2010
Source:
Europlanet Media Centre
Summary:
Scientists report that NASA satellites designed to view the escaping atmosphere of the Sun have also recorded evidence of escaping gas from the planet Mercury. The STEREO mission has two satellites placed in the same orbit around the Sun that the Earth has, but at locations ahead and behind it. This configuration offers multi-directional views of the electrons and ions that make up the escaping solar wind. On occasion, the planet Mercury appears in the field of view of one or both satellites. In addition to its appearance as a bright disk of reflected sunlight, a "tail" of emission can be seen in some of the images.

An image of Mercury's tail obtained from combining a full day of data from a camera aboard the STEREO-A spacecraft. The reflected sunlight off the planet's surface results in a type of over-exposure that causes Mercury to appear much larger than its actual size. The tail-like structure extending anti-sunward from the planet is visible over several days and spans an angular size exceeding that of a full Moon in the night sky.
Credit: Image courtesy of Boston University’s Center for Space Physics

Scientists from Boston University's Center for Space Physics report that NASA satellites designed to view the escaping atmosphere of the Sun have also recorded evidence of escaping gas from the planet Mercury. The STEREO mission has two satellites placed in the same orbit around the Sun that the Earth has, but at locations ahead and behind it.

This configuration offers multi-directional views of the electrons and ions that make up the escaping solar wind. On occasion, the planet Mercury appears in the field of view of one or both satellites. In addition to its appearance as a bright disk of reflected sunlight, a "tail" of emission can be seen in some of the images.

Announcing this new method of observing Mercury and trying to understand the nature of the gases that might make up this tail feature were the topics presented at the European Planetary Science Congress meeting in Rome.

It has been known that Mercury exhibits comet-like features, with a coma of tenuous gas surrounding the planet and a very long tail extending in the anti-sunward direction. From Earth, observations of both of these features can be done using light from sodium gas sputtered off the surface of Mercury. The Sun's radiation pressure then pushes many of the sodium atoms in the anti-solar direction creating a tail that extends many hundreds of times the physical size of Mercury.

"We have observed this extended sodium tail to great distances using our telescope at the McDonald Observatory in Texas," Boston University graduate student Carl Schmidt explained, "and now the tail can also be seen from satellites near Earth." Much closer to Mercury, several smaller tails composed of other gases, both neutral and ionized, have been found by NASA's MESSENGER satellite as it flew by Mercury in its long approach to entering into a stable orbit there.

"What makes the STEREO detections so interesting is that the brightness levels seem to be too strong to be from sodium," commented Schmidt, lead author on the paper presented at EPSC.

Of special interest is the way the tail feature was spotted in the STEREO data. It was not found by the Boston University team, but by Ian Musgrave, a medical researcher in Australia who has a strong interest in astronomy. Viewing the on-line data base of STEREO images and movies, Dr. Musgrave recognized the tail and sent news of it to Boston asking the BU team to compare it with their observations.

"A joint study was started and now we have found several cases, with detections by both STEREO satellites," explained Jeffrey Baumgardner, Senior Research Associate in the Center for Space Physics at Boston University, and the designer of the optical instruments that discovered the exceptionally long sodium tail.

The current focus of the team is to sort out all of the possibilities for the gases that make up the tail. Dr. Christopher Davis from the Rutherford Appleton Laboratory in Chilton, England, a member of the STEREO team responsible for the camera systems on both satellites, is working closely with the Boston University group on refining the brightness calibration methods, and determining the precise wavelengths of light that would get through the cameras' filters.

"The combination of our ground-based data with the new STEREO data is an exciting way to learn as much as possible about the sources and fates of gases escaping from Mercury," said Michael Mendillo, Professor of Astronomy at Boston University and director of the Imaging Science Lab where the work is being done. "This is precisely the type of research that makes for a terrific Ph.D. dissertation," Mendillo added.


Story Source:

The above story is based on materials provided by Europlanet Media Centre. Note: Materials may be edited for content and length.


Cite This Page:

Europlanet Media Centre. "Mercury’s comet-like appearance spotted by satellites looking at the Sun." ScienceDaily. ScienceDaily, 23 September 2010. <www.sciencedaily.com/releases/2010/09/100922081748.htm>.
Europlanet Media Centre. (2010, September 23). Mercury’s comet-like appearance spotted by satellites looking at the Sun. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2010/09/100922081748.htm
Europlanet Media Centre. "Mercury’s comet-like appearance spotted by satellites looking at the Sun." ScienceDaily. www.sciencedaily.com/releases/2010/09/100922081748.htm (accessed October 1, 2014).

Share This



More Space & Time News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Astronomers Spot Largest, Brightest Solar Flare Ever

Astronomers Spot Largest, Brightest Solar Flare Ever

Newsy (Oct. 1, 2014) — The initial blast from the record-setting explosion would have appeared more than 10,000 times more powerful than any flare ever recorded. Video provided by Newsy
Powered by NewsLook.com
French Apple Fans Discover the Apple Watch

French Apple Fans Discover the Apple Watch

AFP (Sep. 30, 2014) — Apple fans in France discover the latest toy, the Apple Watch. The watch comes in two sizes and an array of interchangeable, fashionable wrist straps. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
The Water You Drink Might Be Older Than The Sun

The Water You Drink Might Be Older Than The Sun

Newsy (Sep. 27, 2014) — Researchers at the University of Michigan simulated the birth of planets and our sun to determine whether water in the solar system predates the sun. Video provided by Newsy
Powered by NewsLook.com
First Woman Cosmonaut in 17 Years Blasts Off for ISS

First Woman Cosmonaut in 17 Years Blasts Off for ISS

AFP (Sep. 26, 2014) — A Russian Soyuz spacecraft carrying an American astronaut and two Russian cosmonauts, including the first woman cosmonaut in 17 years, blasted off on schedule Friday. Duration: 00:35 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:

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