Emergence of much smaller stars in early Universe?

Click For Summary

Discussion Overview

The discussion revolves around the emergence of smaller stars in the early Universe, particularly focusing on recent research from Heidelberg University regarding these stars and their unexpected carbon content. Participants explore theoretical implications, potential origins of these stars, and the mechanisms behind carbon production in the context of early star formation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants express curiosity about the Heidelberg University research on early stars that are smaller than previously thought and question the presence of carbon in these stars at such an early stage of the Universe.
  • One participant suggests that the carbon may have originated from previous, more massive stars that had short lifespans.
  • Another participant notes that high redshift quasar spectra indicate that quasars produce significant amounts of carbon, raising questions about the conditions under which this occurs.
  • There is a proposal that quasars, being highly energetic, might create lighter elements like carbon through fusion processes that are not fully understood, drawing parallels to regular stars.
  • A later reply discusses a potential explanation from a journal article that suggests low-mass carbon-rich stars may have formed in binary systems with larger stars that underwent asymptotic giant branch (AGB) processes, which produce and expel carbon.
  • Another participant emphasizes that these low-mass stars likely did not form with carbon but acquired it from their AGB companions during their lifetimes.
  • One participant introduces Rovelli's "Planck stars" concept, which hypothesizes about stars collapsing into black holes and re-emerging, although the connection to carbon and the age of the Universe remains unclear.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the origins of carbon in early stars, with multiple competing views and hypotheses presented regarding the mechanisms of star formation and carbon production.

Contextual Notes

The discussion includes references to specific astronomical phenomena and theoretical models, but limitations exist regarding the assumptions made about the conditions in the early Universe and the definitions of the terms used.

AtomicPunk
Messages
1
Reaction score
0
Anyone have any insight concerning the latest research underway at Heidelberg University... concerning the "smaller than once thought" earliest stars? Any thoughts on why these 'smaller than once thought stars' also contain carbon, when at this early stage of star formation in a very young Universe, they shouldn't yet?

http://www.uni-heidelberg.de/presse...g-message-about-the-end-of-the-dark-ages.html

Dr. Paolo Molaro from the Trieste observatory suspects that they belong to a special – completely new – class of original stars. Any thoughts?
 
Space news on Phys.org
The most likely explanation I can think of is that the carbon must have originated from previous much more massive stars that were short lived
 
High redshift quasar spectra suggest they produce surprisingly high amounts of carbon.
 
Since quasars are probably the most energetic things in the universe other than the initial 'big bang', it does seem plausible that they could produce lighter elements such as carbon through fusion processes that are at present beyond our understanding.
Well, we do understand in the case of regular stars how that happens, and it doesn't seem unreasonable to suggest that conditions similar to a star core might occur within a quasar, or nearby.
 
AtomicPunk said:
Anyone have any insight concerning the latest research underway at Heidelberg University... concerning the "smaller than once thought" earliest stars? Any thoughts on why these 'smaller than once thought stars' also contain carbon, when at this early stage of star formation in a very young Universe, they shouldn't yet?

http://www.uni-heidelberg.de/presse...g-message-about-the-end-of-the-dark-ages.html

Dr. Paolo Molaro from the Trieste observatory suspects that they belong to a special – completely new – class of original stars. Any thoughts?
That Uni Heidelberg press release is based on this article:
http://arxiv.org/abs/1504.05963

This article proposes a reasonable explanation for the earlier puzzle. The class of low-mass carbon rich stars were in a binary pair with a larger star which became what is called "AGB" (asymptotic giant branch).
AGB stars are not so massive that they explode as supernovae. But they are massive enough to develop helium-burning and make carbon. They also expel large quantities of their fusion products including carbon.

The Uni publicity department made the existence of these stars seem more mysterious than the actual professional journal article did. The journal article suggests an explanation and ties up the loose ends.
 
  • Like
Likes   Reactions: |Glitch| and Shobah
Here is a google search for "AGB stars"
https://www.google.com/?gws_rd=ssl#q=agb+star

Here are some lecture notes, an example of what the google search turns up:
http://www2.astro.psu.edu/users/rbc/a534/lec24.pdf

It describes the mechanism by which AGB stars expel fusion products. The AGB companion could be dumping carbon on its dwarf companion. At least the authors of the paper referred to in the press release think that is likely the way this class of stars got their extra carbon.

They were not formed with it, and they did not make it themselves. They got it during their life as member of a binary system.
 
Concerning your third question, you might be interested in Rovelli's "Planck stars" paper (arXiv.org > gr-qc > arXiv:1401.6562), just in case you haven't seen it yet. (This forum has two long intertwined threads about it.) He hypothesizes stars that had collapsed into black holes re-emerging into view upon the evaporation of their event horizon, after an interval very long to those outside it but short to whatever observer could survive the collapse: In one of two black hole scenarios he describes, the collapsed stars would have sizes smaller than the atomic scale but much larger than Planck's, so they would qualify as very small (in volume, not in mass), but I can offer no idea of either the relation of their remaining material to carbon or the relation of their age to the age of whatever universe would surround them. (Rovelli mentions, in passing, a bouncing universe scenario that, like the black hole ones, would rely on quantum pressure.)
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 51 ·
2
Replies
51
Views
6K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 62 ·
3
Replies
62
Views
12K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 24 ·
Replies
24
Views
23K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 8 ·
Replies
8
Views
5K
  • · Replies 1 ·
Replies
1
Views
4K