Featured Research

from universities, journals, and other organizations

Sun's 'DNA' revealed

Date:
July 6, 2011
Source:
CNRS (Délégation Paris Michel-Ange)
Summary:
Solar nitrogen is very different from that of meteorites or the Earth. Scientists reached this conclusion after analyzing samples of solar wind collected by the Genesis space mission launched by NASA in 2001. They succeeded in determining the isotopic composition of the Sun, its “DNA”, which reflects the composition of the cloud of gas and dust that gave rise to the solar system. This work could help to elucidate the phenomena behind the origin of the solar system.

Fitting a target in a sample-holder specially devised for the experiment.
Credit: © CRPG / CNRS

Solar nitrogen is very different from that of meteorites or Earth. A French-American team headed by the Centre de Recherches Pétrographiques et Géochimiques (CRPG-CNRS) de Nancy reached this conclusion after analyzing samples of solar wind collected by the Genesis space mission launched by NASA in 2001. The team succeeded in determining the isotopic composition of the Sun, its "DNA," which reflects the composition of the cloud of gas and dust that gave rise to the solar system. This work, which benefited in particular from the support of CNRS, CNES and the Région Lorraine, could help to elucidate the phenomena behind the origin of the solar system. Results were published on 24 June 2011 in the journal Science and also feature on its cover.

Where does the matter in our solar system come from? How did it form? To answer these questions, scientists focus their studies on the Sun. In fact over 99% of the matter currently present in the solar system is concentrated within the Sun. More importantly, the Sun has conserved the initial composition of the protosolar nebula, the cloud of gas and dust that gave rise to the solar system. This is not the case with most of the other bodies in the solar system, such as Earth, Mars or the meteorites, which -- because they formed at high temperature -- have lost their primitive volatile elements. Consequently, their present composition does not reflect the composition of the protosolar nebula.

The chemical composition of the Sun is known from the analysis of the light that it emits. However, it is impossible to determine from a distance its isotopic abundance. Indeed, there can be different isotopes (14N and 15N for nitrogen; 16O, 17O and 18O for oxygen, etc.) for a single element: while they have the same number of electrons and protons, they differ by their number of neutrons. Determining the nitrogen and oxygen isotopic compositions of the Sun was one of the main objectives of the Genesis mission. The reason? The isotopic ratios of these elements (15N/14N for nitrogen(1), 17O/16O and 18O/16O for oxygen(2)) are very dissimilar between different objects of the solar system, namely Earth, the Moon, Mars, the meteorites, the comets and the giant planets. To explain these variations, it was essential to determine the isotopic composition of the protosolar nebula, in other words the Sun's composition today.

During the Genesis mission, which took place from December 2001 to April 2004, targets were irradiated by solar wind for 27 months. Bernard Marty's team at CNRS's Centre de Recherches Pétrographiques et Géochimiques (CRPG) was then selected by NASA to determine the abundance of nitrogen isotopes in the samples collected. All their analyses(3) point to the same result: solar nitrogen different to nitrogen from Earth. The Sun has 60% less 15N isotope than Earth. In other words, Earth and the meteorites have 60% more 15N, whereas the comets have 300% more 15N. In parallel, an American team has revealed that solar oxygen is also deficient in rare isotopes (17O and 18O) compared to the oxygen on Earth. Their study was also published in the journal Science two weeks ago. Furthermore, the 15N/14N ratio of the Sun is similar to that of Jupiter's atmosphere, analyzed ten years ago by an American space probe. This similarity demonstrates that the giant planets, including Jupiter, captured part of the gas present in the primitive nebula within their atmospheres.

All bodies in the solar system (with the exception of gaseous planets, such as Jupiter) contain an "abnormally" higher quantity of rare nitrogen and oxygen isotopes than the Sun. Such disparities are not observed in the case of non-volatile elements. Characterizing the origin of these enrichments could provide a better understanding of the phenomena that triggered the emergence of our solar system. One of the leads currently being followed is that these variations could result from an intense irradiation of the nebula's residual gas by the young Sun, which at the time had much more energy than today. Photochemical reactions may have enriched the compounds resulting from these reactions with rare isotopes. These compounds would then have been incorporated into meteorites and terrestrial planets. A hypothesis that still needs to be verified…

Notes:

1 -- 14N is the most abundant nitrogen isotope on Earth.

2 -- 16O is the most abundant oxygen isotope on Earth.

3 -- The initial analyses were conducted on samples that were considerably polluted before the flight by 15N nitrogen. They gave rise to results with an uncertainty of +/-20%. NASA then provided fragments from a much less polluted target containing more solar particles. The isotopic composition of the nitrogen was then determined using the new ion probe installed in CRPG in late 2009 (uncertainty of +/- 0.7%).


Story Source:

The above story is based on materials provided by CNRS (Délégation Paris Michel-Ange). Note: Materials may be edited for content and length.


Journal Reference:

  1. B. Marty, M. Chaussidon, R. C. Wiens, A. J. G. Jurewicz, D. S. Burnett. A 15N-Poor Isotopic Composition for the Solar System As Shown by Genesis Solar Wind Samples. Science, 2011; 332 (6037): 1533 DOI: 10.1126/science.1204656

Cite This Page:

CNRS (Délégation Paris Michel-Ange). "Sun's 'DNA' revealed." ScienceDaily. ScienceDaily, 6 July 2011. <www.sciencedaily.com/releases/2011/07/110706094335.htm>.
CNRS (Délégation Paris Michel-Ange). (2011, July 6). Sun's 'DNA' revealed. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2011/07/110706094335.htm
CNRS (Délégation Paris Michel-Ange). "Sun's 'DNA' revealed." ScienceDaily. www.sciencedaily.com/releases/2011/07/110706094335.htm (accessed September 1, 2014).

Share This




More Space & Time News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space Shuttle Discovery's Legacy, 30 Years Later

Space Shuttle Discovery's Legacy, 30 Years Later

Newsy (Aug. 30, 2014) — The space shuttle Discovery launched for the very first time 30 years ago. Here's a look back at its legacy. Video provided by Newsy
Powered by NewsLook.com
Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) — Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) — The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) — Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
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:
from the past week

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