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Why Observe Hydrides? - PowerPoint PPT Presentation

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Why Observe Hydrides?
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  1. Why Observe Hydrides? 1. Part of water network (OH+) 2. Interesting also for other networks (CH2, H2S) 3. Tracers for FUV and X-ray emissions 4. New molecules, not observable from ground

  2. He+ H3+ H2 H2 H+ H2O+ OH+ O+ O CO2 H2 He+, C+ H+ C H2 OH He+ H+ He+ e- H3O+ H2O OH CO O2 H2 O H3+, HCO+ e- HCO+ e- H2O HCO+ H3+ P. Stäuber

  3. Why Observe Hydrides? 1. Part of water network (OH+) 2. Interesting also for other networks (CH2, H2S) 3. Tracers for FUV and X-ray emissions 4. New molecules, not observable from ground

  4. C H3+, HCO+ H, He+, , CH4 CH CH+ , H, , H2 H2 CH3 CH2 CH2+ H2 , H3+, HCO+ e- H2 CH3+ P. Stäuber

  5. H2 O CO H H, O OH, O2 H2S+ SH+ S+ SO+ SO2+ H2 H3+, HCO+, H3O+ H+, C+ H3+, H+ H+, C+ e- H He+ e- H+ He+ OH, O2 e- OH H3S+ H2S S SO SO2 H3+, HCO+, H3O+ C e- OH H3+, HCO+ e- H H2O, e- O SH HSO+ P. Stäuber

  6. Why Observe Hydrides? 1. Part of water network (OH+) 2. Interesting also for other networks (CH2, H2S) 3. Tracers for FUV and X-ray emissions 4. New molecules, not observable from ground

  7. Stäuber, Doty, van Dishoek & Benz, 2005

  8. Stäuber, Doty, van Dishoek & Benz, 2005

  9. AFGL 2591, high-mass YSO, 5 104 y ─ no inner X-rays and UV -··- best fit with X-rays and FUV Stäuber, Doty, van Dishoek & Benz, 2005 Stäuber, Doty, van Dishoek & Benz, 2005

  10. AFGL 2591, high-mass YSO, 5 104 y ─ no inner X-rays and UV -··- best fit with X-rays and FUV Stäuber, Doty, van Dishoek & Benz, 2005

  11. Stäuber, Doty, van Dishoeck, Jorgensen and Benz, 2004

  12. Stäuber, Doty, van Dishoek & Benz, 2005

  13. TMC 1, low-mass YSO, Class 1, 105 y Lx = 1032 erg/s 1030 erg/s 1028 erg/s Lx = 0 erg/s erg/s erg/s erg/s Stäuber Jørgensen, v.Dishoeck, Doty & Benz, 2006

  14. Inner FUV radiation and X-rays enhance the formation of basic hydrides with positive charge (col. dens.) X-rays/none X-rays/FUV • CH 11.6 3.4 • CH+ 70000 0.5 • OH 0.6 0.5 • OH+ 1390 358 • SH 3.3 2.2 • SH+ 35000 1400 None = model without YSO X-rays or FUV X-ray= model with X-rays, but no FUV FUV = model with FUV, but no X-raysCalculations for AFGL 2591 by Stäuber et al. 2005 FUV/X-ray sensitive very FUV sensitive not sensitive very X-ray sensitive slightly X-ray sensitive very X-ray sensitive

  15. Main formation reactions in YSO envelopes due to X-rays • CH2 + H → CH + H2 • H3+ + C → CH+ + H2 and HCO+ + C → CH+ + CO • H2O + γ→ OH + H • H2O + He+ → OH+ + H + Heand H3+ + OH → OH+ + H + H2 • H3+ + S → SH+ + H2 Stäuber et al. 2005

  16. Molecules and Lines Frequency Transition Remarks Col.depth Prio GHZ (2", AFGL 2591) CH 536.7 3/2 → 1/2 X-ray tracer, triplet 4.7E+12 *** 1470.7 5/2 → 3/2 4 lines ** 1661.1 2 → 1 3 lines ** CH+ 835.1 1 → 0 FUV tracer4.9E+08 * 1669.1 2 → 1 * NH 974.5 1 → 0 use? 4.8E+12 NH+ 1038.1 use? 7.9E+08

  17. Molecules and Lines (Cont.) Frequency Transition Remarks Col.depth Prio GHz OH already in water program 1.2E+15 OH+ 971.8 1→ 0 X-ray tracer 7.0E+09* triplet 1892.2 2 → 1 4 lines * SH 526 2.7E+12 ** 1382.9 SH+ 526.05 2 → 1 X-ray tracer,3.0E+12 ** triplet

  18. Molecules and Lines (Cont.) FeH All very weak. Why observe? SiH PH CaH LiH

  19. Neutral Molecules and Lines: Selection Frequency Transition Remarks Prio GHz CH 536,7 3/2 → 1/2 X-ray tracer, *** ≈H3O+1033.0 ?? triplet ** SH 526? ?? X-ray tracer ** 1382.8 v=1,2 triplet **

  20. Ionized Molecules and Lines: Selection Frequency Transition Remarks Prio GHz SH+ 526.05 2 → 1 X-ray tracer, ** triplet ** OH+ 971.8 1→ 0 X-ray tracer * triplet 1892.2 2 → 1 4 lines * CH+ 835.1 1 → 0 FUV tracer, ≈H2O * 1669.2 2 → 1 *

  21. Objects and Strategy • Four sources with deep integrations in 7 molecules and 7 lines (each 45 minutes initially) • start with: CH, SH, NH, SH+, OH+, CH+, maybeO2 21 hr • 2. Twelve sources of Water KP list objects with 4 lines selected from above (or deeper integrations or second line of selection 1 ) • 24 hr 6 low-mass stars, class 0 and 1 (with H2O detections) 5 high-mass 1 intermediate-mass stars

  22. To Do • Vary initial abundances and other parameters • Calculate antenna temperature for all lines • Select molecules • Select lines • Select objects from water KP list • Ancillary data (ground based observations)