Half of All Stars in Galactic Halos: Potential to Rethink Mass Estimates?

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Discussion Overview

The discussion revolves around the claim that half of all stars in galaxies may be rogue stars located in large, faint halos, challenging previous estimates that suggested only 5% of stars fell into this category. Participants explore the implications of this finding for models of galactic formation and mass estimates.

Discussion Character

  • Exploratory, Debate/contested, Technical explanation

Main Points Raised

  • Some participants note that if validated, the finding could lead to a reevaluation of galactic mass estimates due to the previously unaccounted for mass of rogue stars.
  • Others suggest that the reevaluation may also involve understanding how the light from these stars affects theories of reionization and halo size, which could have further implications for mass distribution.
  • A participant mentions that the models discussed in the paper are based on the Lambda Cold Dark Matter (LCDM) framework, implying that this may not pose a problem for existing theories.
  • One participant emphasizes the role of dark matter in making sense of galactic structures, suggesting that without it, the implications of the rogue star findings may be difficult to interpret.

Areas of Agreement / Disagreement

Participants express varying views on the implications of the rogue star findings for galactic mass estimates and models. There is no consensus on the extent of the impact or the specific areas that would require reevaluation.

Contextual Notes

Limitations include the reliance on the original publication and the potential for varying interpretations of the implications of rogue stars on galactic formation models.

jim mcnamara
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I cannot get to the original Science publication to cite it. Science Now has a précis:
http://www.latimes.com/science/scie...ight-background-ebl-ciber-20141106-story.html

So the information below is not firsthand.

The claim is that one half of all stars are rogue stars, which are stars which well out into a very large, faint halo around galaxies. The article mentions that previously about 5% of all stars were thought to fall into this category.

It goes on saying that this finding, if validated, would cause researchers to revisit models of galactic formation.
Question: why would that cause reevaluation - a lot more previously unaccounted for mass? Does this finding have the potential to invalidate existing estimates of galactic mass?

Thanks for any comments.
 
Space news on Phys.org
Thanks for that.
 
jim mcnamara said:
Question: why would that cause reevaluation

From the article it looked more like a reevalution of how the light from these stars would inform on reionization (perhaps makes it even more difficult to understand) and halo size. The latter would have implications for masses and their distribution, I would think. I just scanned the provided paper, and it seems their models are based on LCDM, so presumably no problem there.
 
Dark matter is the short answer. Without it, nothing makes a whole lot of sense.
 

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