New red dwarf count and He-4 abundance

In summary, the new estimate on the number of red dwarf stars in the universe, as proposed by van Dokkum and Conroy, suggests that the proportion of He/H may be lower than the current estimate of 24%. This is due to the fact that more mass would be tied up in low-mass stars, such as red dwarfs, in which He/H<0.24. However, it is unclear how many more times the number of low-mass stars would need to be increased in order to have a significant influence on the proportion of He/H in the universe. Additionally, it is noted that vast numbers of red dwarf stars do not disprove the LCDM model, and previous conjectures involving even more vast numbers of
  • #1
TrickyDicky
3,507
27
Does the new estimate on the number of red dwarf stars in the universe suggest a different proportion of He/H? (current helium abundance estimate is 24%)
Would it be lower since more mass would be tied up in low-mass stars (like red dwarfs) in which He/H<0.24.?
If not, how many more times should the number of low-mass stars be increased to have some influence on the proportion He/H of the universe?

New estimate by van Dokkum and Conroy:
http://arxiv.org/pdf/1009.5992v1
http://www.universetoday.com/80955/red-dwarf-discovery-changes-everything/
http://www.nytimes.com/2010/12/02/science/space/02star.html?_r=1&ref=science
 
Space news on Phys.org
  • #2
Bah, how many red dwarfs do you need to disprove the LCDM model? Hint - vast numbers of red dwarf stars do not do the trick any more than even more vast numbers of brown dwarfs previously postulated. Optical peaks in the CMB have long since ruled out these conjectures.
 
  • #3
Chronos said:
Bah, how many red dwarfs do you need to disprove the LCDM model? Hint - vast numbers of red dwarf stars do not do the trick any more than even more vast numbers of brown dwarfs previously postulated. Optical peaks in the CMB have long since ruled out these conjectures.

My question was specific enough not to be answered with doctrine, but rather with current knowledge about stellar helium nucleosynthesis.
 

1. What is a red dwarf?

A red dwarf is a small, cool, and dim star that is the most common type of star in the universe. They typically have a mass of less than half that of the sun and have surface temperatures of around 3,000-4,000 Kelvin.

2. What is the significance of the new red dwarf count and He-4 abundance?

The new red dwarf count and He-4 abundance is significant because it sheds light on the composition and evolution of our universe. The number of red dwarfs and the amount of helium-4 present can give us insights into the formation and age of galaxies, as well as the overall structure of the universe.

3. How was the new red dwarf count and He-4 abundance determined?

The new red dwarf count and He-4 abundance was determined through observations and analysis of data collected by the European Space Agency's Gaia satellite. This satellite measured the positions, distances, and properties of over 1 billion stars, including red dwarfs, in the Milky Way.

4. What is the current estimate for the number of red dwarfs in the Milky Way?

Based on the data collected by the Gaia satellite, the current estimate for the number of red dwarfs in the Milky Way is around 250 billion. This is significantly higher than previous estimates and suggests that red dwarfs may be more prevalent in the universe than previously thought.

5. How does the He-4 abundance in red dwarfs compare to other stars?

The He-4 abundance in red dwarfs is significantly lower than in other stars. This is because red dwarfs are low-mass stars that have not undergone significant nuclear reactions, resulting in a lower amount of helium-4 present in their atmospheres. This is also why red dwarfs are often referred to as "failed stars" as they do not have enough mass to sustain fusion reactions like larger stars.

Similar threads

  • Astronomy and Astrophysics
Replies
9
Views
2K
Replies
15
Views
2K
  • Astronomy and Astrophysics
Replies
23
Views
4K
Replies
13
Views
2K
  • Sci-Fi Writing and World Building
Replies
21
Views
1K
Replies
1
Views
3K
  • Astronomy and Astrophysics
3
Replies
77
Views
7K
  • Astronomy and Astrophysics
Replies
9
Views
5K
  • Astronomy and Astrophysics
Replies
4
Views
2K
  • Astronomy and Astrophysics
2
Replies
60
Views
10K
Back
Top