Presentation is loading. Please wait.

Presentation is loading. Please wait.

Photodissociation Workshop Kasteel oud Poelgeest, Leiden 3-5 February2015 Photodissociation in the Solar Nebula: Models and Meteorites James R. Lyons School.

Similar presentations


Presentation on theme: "Photodissociation Workshop Kasteel oud Poelgeest, Leiden 3-5 February2015 Photodissociation in the Solar Nebula: Models and Meteorites James R. Lyons School."— Presentation transcript:

1 Photodissociation Workshop Kasteel oud Poelgeest, Leiden 3-5 February2015 Photodissociation in the Solar Nebula: Models and Meteorites James R. Lyons School of Earth & Space Exploration Arizona State University

2 Isotopic Photodissociation Topics Spin-forbidden CO 2 photolysis – Mars atmosphere SO 2 photolysis (~200 nm) – early Earth atmosphere Oxygen isotopes in Sun and meteorites CO photodissociation in solar nebula & protoplanetary disks

3 Geochemical delta notation

4 Mass-independent fractionation on a 3-isotope plot  17 O SMOW  18 O SMOW slope 0.52 (TF)  17 O O-MIF

5 Nair et al. (1994) 167 nm 227 nm Schmidt et al. 2013

6 185 nm Mars atmosphere Schmidt et al. 2013

7 Farquhar et al pyrites barites Record of S-MIF in sedimentary rocks

8 Kasting 2001 (from Kasting et al. 1989) pO 2 < atm Low-O 2 atmospheric sulfur chemistry Pavlov & Kasting 2002

9 v2v2 SO 2, H 2 S and CS 2 absorption cross sections

10 ab initio: Ran et al v 2 =9 8 7 Lyons 2008

11 Wavelength shift of SO 2 isotopologues Lyons

12 Lyons (2007) Calc rock values

13 Ono, Whitehill, Lyons 2013 SO 2 + hv experiments

14

15

16

17 Ayres et al G94 HR96 Oxygen isotopes in the solar system McKeegan et al (inferred) photosphere (2004)

18 Gharib-Nezhad et al HR96 Oxygen isotopes in the solar system McKeegan et al (inferred)

19 Self-shielding in a 2-D disk snowline H2OH2O

20 Lyons & Young 2005 Self-shielding of CO in outer disk surface G 0 =500

21 Chakraborty et al. 2008, 2012

22

23

24 Chakraborty et al SiO + OH  SiO 2 + H

25 HD 36981

26 Influence of CO E   ) – X(0) dissociation probabilities Lyons (2014)

27 12 C 16 O transmission spectra measured at Soleil

28 Stark et al Isotopic CO E   ) – X(0) absorption cross sections

29

30

31 Summary 1.Spin-forbidden CO 2 photolysis: No hyperfine assist. High quality ab initio cross sections from Schmidt et al. (2013). 2.SO 2 photolysis: Isotopic shifting of vibronic peaks, with 32 SO 2 rotational features copied, works. SO 2 is not the MIF source. 3.Solar photosphere oxygen isotopes consistent with Genesis inferred photosphere isotope ratios. Latest CO vib f-values close to HR96. 4.High-resolution CO E-X & C-X isotopic cross sections exhibit C 16 O and C 18 O self-shielding initially, but not at later times. Need 1217 and 1218 dissociation probabilities for CO E(0)-X.

32 Acknowledgements Colaborators: Glenn Stark, Alan Heays, Michelle Eidelsberg, Jean-Louis Lemaire Steve Federman, Douglas Blackie, Juliet Pickering, Andreas Pack, Tom Ayres Student (ASU): Ehsan Gharib-Nezhad Soleil DESIRS beamline: Nelson de Oliveira, Laurent Nahon Funding: NASA Origins of Solar Systems NASA Astrobiology/Exobiology

33

34


Download ppt "Photodissociation Workshop Kasteel oud Poelgeest, Leiden 3-5 February2015 Photodissociation in the Solar Nebula: Models and Meteorites James R. Lyons School."

Similar presentations


Ads by Google