Neon , Opacity the Universe and Everything

Jeremy DrakeSmithsonian Astrophysical Observatory

•2004: The “solar model problem”

•2005: Neon in late-type stars

•2006: –What solar model problem? –What is the real solar neon abundance?–The Universe and Everything

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c.2003 new solar photospheric abundance analyses using 3-D hydrodynamic atmosphere models found C, N and O abundances lower by 25-30%(Asplund et al 2004)

The rise and fall of the solar oxygen abundance (Ayres et al 2006)

• “At recent rate of decline, the Sun will run out of oxygen in about 2015”

G.W. Bush takes office

2004: Solar Model Breaks!

The Solar Model Problem• Models calculated with

Asplund et al (2004) abundances fail to predict sound speed, He abundance and depth of convection zone inferred from helioseismology (Bahcall et al 2005; Antia & Basu 2005)

• Opacity problem but appears beyond uncertainties in current atomic data (Seaton & Badnell 2004; Badnall et al. 2005; Bahcall et al. 2005)

Bahcall et al (2005)Antia & Basu 2004, Bahcall et al 2005:

Might be fixed IF solar Ne is ~2.5x higher

Badnell et al (2005)

OP-OPAL opacitiesStandard solar model

But cosmic Neon abundance known for 50 years…

Aller (1957)

Ne/O=0.15

…in nebulae and the solar corona…

Pottasch (1963)

Ne/O=0.12

Pottasch (1963)

It’s…

Acton et al (1976)

• Average of 25 different measurements of OVIII/Ne IX X-ray fluxes ==> N(O)/N(Ne)=0.21+/- 0.07

Ne/O=0.21

…always…Meyer (1985)

Ne/O=0.14

…seemed…Grevesse, Noels & Sauval (1996)

(note log10+12 scale)

Ne/O=0.16

…to be..

Widing (1998):Newly-emerged active regions

Ne/O=0.14

…about

Henry (1998): HII regions in MW and spiral galaxies

Ne/O=0.16

Chandra, XMM: Coronal abundances - a Neon Surprise

• The first spectra from Chandra revealed remarkably strong Ne X lines

Ne X

O VIIINe IX

Fe XVIIPre-flightsimulation

Ne/O Ratios from Coronal Spectra (Drake & Testa 2005)

• UseT-insensitive ratio constructed from O VIII, Ne IX and Ne X

• Integration over test DEM(T) --> systematic errors ~<0.1 dex

Ne/O Ratios in Stars of the Local Cosmos

• Ne/O remarkably constant and 2.7 times higher than Asplund et al (2004) - just right to fix the solar model!

Ne/O=0.42

Drake & Testa (2005)

Just a FIP Effect?

Brinkman et al (2001)

Sun

HR1099 vs Sun

Guedel (2004)

Fe fractionation in stellar coronae

Ne/O Ratios in Stars of the Local Cosmos

• Ne/O remarkably constant and 2.7 times higher than Asplund et al (2004) - just right to fix the solar model!

Drake & Testa (2005)

Objection!

• Quiet sun CDS EUV Ne IV-VI, O III-V: “…the photospheric abundance of neon is not responsible for the discrepancies between standard solar models and

helioseismological observations” - Young (2005)

• Re-analysis of old solar SMM X-ray Ne IX, O VIII: "...the enhanced-neon hypothesis will not resolve

the current controversy" - Schmelz et al (2005)

Dead Horse

• Solar + local cosmic abundance: "The evidence is thus stacked against the solar Ne/O ratio being as high

as 0.4 ... the solar model problem still awaits a solution.” - Asplund et al, astro-ph/0510377

• Delahaye & Pinnsoneault (2006): “…models constructed with low oxygen and high neon are

inconsistent with the solar sound speed profile”

What Solar Model Problem?• Re-analysis and review of solar CNO

abundances and non-LTE corrections: “we obtain intermediate abundances…the errors are too large to conclude there is a solar abundance problem” - Pinsonneault & Delahaye (2006)

• Fine analysis of IR CO bands giving O/H=8.85: “…our conclusions do not support such

a revision [of the O abundance]” - Ayres et al (2006)

Ayres et al (2006)

What is the real solar Ne abundance?

McKenzie & Feldman (1992)

Ne/O=0.08

Ne/O=0.2

P78 SOLEX

Ne Fractionation in Solar Corona (Drake 2006)

• Which, if any, solar coronal measurements represent underlying Sun?

• Rising Ne/O vs T reminiscent of higher values in more active stars

Solar Ne/O depends on plasma T

Based on P78 fluxes (McKenzie & Feldman 1992)

The Universe and Everything

“The typically derived Ne/O ratios in hot stars, H II regions and planetary nebulae are in very good agreement with our advocated solar value”- Asplund et al (2005 astro-ph/0510377)

Current Evidence for “standard” Ne/O

• Ne/O=0.19,0.2 X-ray ISM absorption

measurements using X-ray binaries (Juett et al 2006, Yangsen & Wang 2006)

• Ne/O~0.15 most(?) c1990-2000 H II

region studies (eg Henry 1998; (but ORL vs CEL

issue?!))

• Ne/O=0.4 Heliopause, local ism pickup ions (Frisch & Slavin 2004, Gloeckler & Geiss 2004)

• Ne/O=0.4 ISM toward Crab (Pollock et al. 2005)

• Ne/O~>0.5 IGM (Nicastro et al 2005)

• Ne/O=0.3-0.5 B stars, BA supergiants (Sigut

1999,Killian et al 1994, Przybilla et al 2005, Cunha et al 2006)

• Ne/O=0.3 PNe (Liu et al 2003, Perinoto et al 2004,

Stranghellini et al 2006)

Evidence for higher Ne/O

Drake (2006)

Ne/O=0.15

Ne/O=0.4

Supernova Yield Problems?

Henry (1998): HII regions in MW and spiral galaxies

Woosley & Weaver (1995)

Samland(1998)

Nomoto etal (1997)

Conclusion• Many cosmic sources now indicate Ne/O

about x2 higher than the currently favoured solar ratio of Ne/O=0.15

• The solar outer atmosphere indicates significant fractionation of Ne content is at work. Ne/O is plausibly depleted in the corona and the true solar Ne abundance about x2 higher.

• The answer is still important for the solar model, supernova metal production and the metal content and evolution of the universe.