1 / 12

Linking Lithium and Cheetos

Linking Lithium and Cheetos. Dispersion In Lithium. Lithium destroyed (2.5 MK) during PMS - probe of stellar interior Lithium abundance dispersion at fixed mass, composition and age (IC2602, alpha Per, Pleiades) - why? - not predicted by standard stellar models

hamish
Download Presentation

Linking Lithium and Cheetos

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Linking Lithium and Cheetos

  2. Dispersion In Lithium

  3. Lithium destroyed (2.5 MK) during PMS - probe of stellar interior • Lithium abundance dispersion at fixed mass, composition and age (IC2602, alpha Per, Pleiades) - why? - not predicted by standard stellar models - flaw in understanding of stellar structure/evolution

  4. Li and K resonance line formation is similar • Scatter in Li eqw mirrored by K eqw scatter? - K is not easily depleted - Li scatter not depletion related - temperatures or line formation effects (i.e. spots)?

  5. Updated Data shows no K scatter • Lithium scatter still significant • Not line-formation effects

  6. Analytic spot models - can reproduce Li EQW scatter w/o K EQW scatter (80 % coverage) • 2 Spectroscopic signatures discount analytic spot models: - Li 6104 and 6707 syntheses differences - CN too strong in spot models

  7. A(Li) A(Li) Diff HII250 3.09 3.03 0.06 HII263 2.96 2.97 -0.01 HII916 2.52 2.60 -0.08 Spot Model 3.32 2.90 0.42 3.62 3.02 0.60

  8. CN Discounts Spot Models • Dotted: Analytic Spot Model with T=5225 K • Solid: Synthetic Spectrum with T=5225 K • Spot CN 3-5 times stronger than non-spot • Non-spot CN strengths consistent with observations

  9. Real abundance dispersion • Signature of variable PMS depletion from radius differences? • M-dwarfs, rapid rotators and active stars are “puffy” - Spots inhibit convective energy transport, and star puffs up - rapid rotating, active stars deplete less Li • Same mass stars have different PMS Li depletion

  10. 10 % Radius Increase= factor of 2.5 increase in surface lithium • Qualitatively consistent with Yee and Jensen 2010 - suggest a 10-20% radius increase can resolve Li depletion ages with HR diagram model ages

  11. Variable spot coverage can make stars of same mass, age and composition “puffy” • “Puffy” stars deplete less lithium in the PMS • Eventually stars settle down and lose “puffyness” • Retain signature of PMS “puffyness” resulting in real Lithium abundance dispersions for stars of single mass, age and composition

More Related