1 / 11

Inti didn’t form in the X wind (and neither did most CAIs)

Inti didn’t form in the X wind (and neither did most CAIs). Steve Desch Arizona State University Harold Connolly, Jr. CUNY Kingsborough. Outline of Talk. Diving into Inti Inti didn’t form in an X-wind... ...but it ended up in a comet anyway, because. Inti Introduced.

najwa
Télécharger la présentation

Inti didn’t form in the X wind (and neither did most CAIs)

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. Inti didn’t form in the X wind(and neither did most CAIs) Steve Desch Arizona State University Harold Connolly, Jr. CUNY Kingsborough

  2. Outline of Talk • Diving into Inti • Inti didn’t form in an X-wind... • ...but it ended up in a comet anyway, because...

  3. Inti Introduced Comet 81P/Wild 2Scattered into present orbit in 1974; was previously a member of the Kuiper Belt Scattered Disk Probably formed at 10-30 AU Zolensky et al (2006) Stardust Sample Track 25 called ‘Inti’. It’s a CAI, formed (by condensation) at > 1700 K.

  4. Shu et al. (1996, 2001) X-wind windicated? 1. Gas (H2), small (< 100 um) solids rapidly funneled away from CAI-forming zone 2. Large (> 100 um) “proto-CAIs” enter Reconnection Ring gas(H+) ~ 10-16 g cm-3 3. CAIs grow by evaporation / recondensation here 4. CAIs flung by X-wind into comets. rockvapor ~ 10-12 g cm-3

  5. X-wind = eXtra-oXidizing Gas in reconnection ring ionized, funneled onto star. Shu et al. (2001) estimate (from protostellar X-ray emission) T= 8 x 106 K, ne = 108 cm-3 (gas ~ 10-16 g cm-3) between flares, in reconnection ring. CAIs grow in reconnection ring by re-condensation following flares, from rock vapor (rockvapor ~ 10-12 g cm-3) Fedkin & Grossman (2006) Intrinsic fO2 of CAI vapor > IW+1 (Kozul et al. 1988) CAIs form in reconnection ring, where fO2 ~ 106 x solar, near IW

  6. Inti Revealed Inti itself is small, < 10 microns Inti contains within its spinel grains of osbornite, (Ti,V)N (likely condensates).

  7. Redox Redux fO2 during CAI formation known to be < IW-6 from Ti4+/Ti3+ ratios in fassaite and rhönite (Beckett 1986, Krot et al. 2000) Osbornite-bearing CAI recently found in CH/CB Isheyevo, recognized as formed in the solar nebula (Meibom et al. 2007), demands C/O = 0.91-0.94 (IW-7) (Ebel 2006) Osbornite in Inti shows it also formed in the gas of the solar nebula!

  8. Solar nebula ebb and flow ‘Nice model’ (Tsiganis et al. 2005; Gomes et al. 2005): the outer planets formed much closer to Sun r (AU) 5 10 15 20 25 30

  9. Minimum mass solar nebula (Weidenschilling 1977), with (r) r^(-1.50), must be updated! Desch (2007) shows (r) r^(-2.17) !

  10. Outer Solar Nebula = Decretion Disk All viscously evolving disks viscously spread outward. Mass distribution can be matched by a spreading disk, with outward mass flow (Desch 2007). Steady-state solution with outward mass flow also matches (Desch 2007.) If (r) r^(-p) and T(r)  r^(-q), mass must flow outwards if p+q > 2(Takeuchi & Lin 2002) Gas, CAIs moved from a few AU to > 10 AU in < 10 Myr Desch (2007, in revision)

  11. Conclusions • X-wind predicts fO2 where CAIs formed > IW. But CAIs overall formed in solar gas, < IW-6 (rhönite / fassaite), and Inti in particular at IW-7 (osbornite). • Inti too small to enter reconnection ring as a proto-CAI; probably too small even to be ejected by X-wind. • Nice model for initial planet positions used by Desch (2007) to derive new “minimum mass solar nebula”. Derived density profile so steep, mass must have flowed outward, from a few AU to > 10 AU in < 10 Myr. • Inti (like all CAIs) formed in the solar nebula; it was transported by disk dynamics to comet-forming zone.

More Related