Featured Research

from universities, journals, and other organizations

Chemical composition of red giant star with more carbon than oxygen in its atmosphere

Date:
January 17, 2010
Source:
University of Granada
Summary:
Researchers have conducted the most complete analysis of the chemical composition and evolutionary state of a spectral type R carbon star. The presence of carbon is essential for the possible development of life in the universe, and therefore explaining its origin is of vital importance.

The attached figure represents the temporary hydrodynamic development (projection in the X-Y plan) of the binary system made up of a helium white dwarf and the core of a red giant, from the zero instant until their complete fusion, in a time of about 6,400 seconds. Every box has an estimated size of about the radius of the Sun. The colours are proportional to the logarithm of density (black is less dense, white is denser).
Credit: Image courtesy of University of Granada

What are the peculiar type-R stars made? Where does the carbon present in their shell come from? These are the questions to be solved by a research work conducted by scientists of the department of Theoretical and Cosmos Physics of the University of Granada (Spain), where they have analysed the chemical composition and the evolutionary state of spectral type R carbon stars to try to explain the origin of the carbon enrichment present in its atmosphere.

Up to now, there had hardly been performed chemical analysis for this type of start. Type-R stars are peculiar red giant stars, as they show a higher presence of carbon than oxygen in their atmosphere (the usual composition in the Universe is exactly the opposite). They can be classified in hot-R starts and cold-R stars, depending on their effective temperature.

In the case of R-cold stars, this is the first chemical analysis of these characteristics carried out worldwide, whereas for R-hot stars, the existing chemical analyses were very old (more than 25 years) and with a lower spectral resolution than that of the UGR study.

The research has been conducted by Olga Zamora Sαnchez and supervised by professors Carlos Abia and Inmaculada Domνnguez. The scientists of the University of Granada have also studied the essential observational features of type-R stars (distribution in the Milky Way, kinematics, luminosity, etc.) .

A 23-star sample

This research work has determined the chemical composition of a 23 type-R star sample (both hot and cold), using spectrums in the optics with high-spectral resolution, in order to obtain information about the origin of this type of stars. To this end, the scientists performed observations with a 2.2-metre in diameter telescope placed in Calar Alto (Almeria), and carried out a chemical analysis of elements such as carbon, oxygen, nitrogen, lithium and other heavy metals, such as technetium, strontium, barium or lanthanum.

Thus, the scientists have concluded that R-cold stars are identical to type-N stars (or normal carbon stars) originated in the AGB phase, whereas R-hot stars are different. About 40% of the R-hot stars of the sample were erroneously classified up now, and therefore the portion of these stars with regard to red giant stars could be considerably reduced regarding previous estimations thanks to this work.

The most comprehensive analysis

The analysis of the University of Granada is the most complete conducted worldwide up to now (from an observational and theoretical approach) about type-R spectral stars. Besides, the scientists have carried out a numeric simulation for the first time of the most favourable scene for the formation of a R-hot star: the fusion of a helium white dwarf with a red giant. In the end, this scene has turned out to be unviable, and therefore the explanation of the origin of R-hot stars keeps representing a challenge for present star and nucleosynthesis development models.

Although the UGR scientists warn that this type of study has not immediate applications, the information obtained could be very valuable in the future as carbon, as everybody knows, is very important for the possible development of life in the Universe. Therefore, they say, explaining the origin of this element in the stars will be useful to study the production of one of the basic ingredients of life that we know.

The results of this research work will be sent for its publication in the near future in the journal Astronomy & Astrophysics.


Story Source:

The above story is based on materials provided by University of Granada. Note: Materials may be edited for content and length.


Cite This Page:

University of Granada. "Chemical composition of red giant star with more carbon than oxygen in its atmosphere." ScienceDaily. ScienceDaily, 17 January 2010. <www.sciencedaily.com/releases/2010/01/100114081712.htm>.
University of Granada. (2010, January 17). Chemical composition of red giant star with more carbon than oxygen in its atmosphere. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2010/01/100114081712.htm
University of Granada. "Chemical composition of red giant star with more carbon than oxygen in its atmosphere." ScienceDaily. www.sciencedaily.com/releases/2010/01/100114081712.htm (accessed July 29, 2014).

Share This




More Space & Time News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) — The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
NASA EDGE: OCO-2 Launch

NASA EDGE: OCO-2 Launch

NASA (July 25, 2014) — NASA EDGE webcasts live from Vandenberg AFB for the launch of the Oribiting Carbon Observatory-2 (OCO) launch. Video provided by NASA
Powered by NewsLook.com
This Week @ NASA, July 25, 2014

This Week @ NASA, July 25, 2014

NASA (July 25, 2014) — Apollo 11 celebration, Next Giant Leap anticipation, ISS astronauts appear in the House and more... Video provided by NASA
Powered by NewsLook.com
Space to Ground: Coming and Going

Space to Ground: Coming and Going

NASA (July 25, 2014) — One station cargo ship leaves, another arrives, aquatic research and commercial spinoffs. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
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