Why Observe Hydrides

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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

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

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C
H3, HCO
H,
He,
,
CH4
CH
CH
, H,
,
H2
H2
CH3
CH2
CH2
H2
,
H3, HCO
e-
H2
CH3
P. Stäuber
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H2
O
CO
H
H, O
OH, O2
H2S
SH
S
SO
SO2
H2
H3, HCO, H3O
H, C
H3, H
e-
H, C
H
He
e-
H
He
OH, O2
e-
OH
H2S
H3S
S
SO
SO2
H3, HCO, H3O
C
OH
e-
e-
H3, HCO
H
O
H2O, e-
SH
HSO
P. Stäuber
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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

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Stäuber, Doty, van Dishoek Benz, 2005
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Stäuber, Doty, van Dishoek Benz, 2005
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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
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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
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Stäuber, Doty, van Dishoeck, Jorgensen and Benz,
2004
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Stäuber, Doty, van Dishoek Benz, 2005
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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
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• 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-rays
  Calculations 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
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Main formation reactions in YSO envelopes due to
X-rays

• CH2 H ? CH H2
• H3 C ? CH H2 and HCO C ? CH
  CO
• H2O ? ? OH H
• H2O He ? OH H Heand H3 OH ? OH
  H H2
• H3 S ? SH H2

Stäuber et al. 2005
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Molecules and Lines
Frequency Transition Remarks Col.depth Prio
GHZ (2", AFGL 2591) CH
536.7 3/2 ? 1/2 X-ray tracer, triplet 4.7E12
1470.7 5/2 ? 3/2 4 lines 1661.1 2 ?
1 3 lines CH 835.1 1 ? 0 FUV tracer
4.9E08 1669.1 2 ? 1 NH 974.5 1
? 0 use? 4.8E12 NH 1038.1 use?
7.9E08
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Molecules and Lines (Cont.)
Frequency Transition Remarks Col.depth Prio
GHz OH already in water
program 1.2E15 OH 971.8 1? 0 X-ray
tracer 7.0E09 triplet 1892.2 2 ?
1 4 lines SH 526 2.7E12 1382.9
SH 526.05 2 ? 1 X-ray tracer,
3.0E12 triplet
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Molecules and Lines (Cont.)
FeH All very weak. Why observe? SiH
PH CaH LiH
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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 v1,2 triplet
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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
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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,
  maybe O2 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
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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)

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