Why Observe Hydrides?
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Eidgenössische Technische H ochschule Zürich Sw iss Federal Institute ofTechnology, Zürich W ater K ey Program H erschel/H IFI H ydrides PascalStäuber Ew ine van D ishoeck JesJørgensen Steven D oty A rnold Benz
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Why Observe Hydrides?. 1. Part of water network (OH + ) 2. Interesting also for other networks (CH 2 , H 2 S) 3. Tracers for FUV and X-ray emissions 4. New molecules, not observable from ground. He +. H 3 +. H 2. H 2. H +. H 2 O +. OH +. O +. O. CO 2. H 2. He + , - PowerPoint PPT Presentation
Transcript of Why Observe Hydrides?
Eidgenössische Technische Hochschule Zürich
Swiss Federal Institute of Technology, Zürich
Water Key ProgramHerschel/HIFI
Hydrides
Pascal StäuberEwine van Dishoeck
Jes JørgensenSteven DotyArnold Benz
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
H2OH3O+ OH
H2O+ OH+ O+
O2
OH2
H2
H2
H2
H3+
H3+, HCO+
H+
H+
H+
e-
e-
He+
He+, C+
OHC
OCO
He+
HCO+
HCO+e-
H3+
H2O
CO2
He+
,xx
x
x
H2
P. Stäuber
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
CH3
CH3+
CH2
CH4 CH
CH2+
CH+
H2
He+,
H3+,
HCO+ e-
H2FUV
xFUV
FUV
FUVx , FUV
FUV H2
x , H,FUV
x ,FUV
C
FUVH,
H3+, HCO+
FUV ,
FUVH2
P. Stäuber
H2SH3S+ S
H2S+ SH+ S+
SO
SO+H
H2
H, O
H
O
H3+, HCO+, H3O+
H+
O
e-
He+
H+, C+
H2O, e-
CO
CSO2
SH
SO2+
,x
xx
HSO+
H3+, HCO+,
H3O+e-
OH, O2 OH
H3+,
H+
OH, O2
e-
OHH
e-
H2
He+
e-H3+,
HCO+
x
H+,C+
,x
P. Stäuber
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
Stäuber, Doty, van Dishoek & Benz, 2005
Stäuber, Doty, van Dishoek & Benz, 2005
Stäuber, Doty, van Dishoek & Benz, 2005Stäuber, Doty, van Dishoek
& Benz, 2005
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
AFGL 2591, high-mass YSO, 5 104 y
-··- best fit with X-rays and FUV─ no inner X-rays and UV
Stäuber, Doty, van Dishoeck, Jorgensen and Benz, 2004
Stä
ub
er,
Do
ty, v
an
Dis
ho
ek
& B
en
z, 2
00
5
Stäuber Jørgensen, v.Dishoeck, Doty & Benz, 2006
erg/serg/serg/s
TMC 1, low-mass YSO, Class 1, 105 y
Lx = 1032 erg/s
1030 erg/s
1028 erg/s
Lx = 0 erg/s
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 X-ray sensitive
very FUV sensitive
not sensitive
very X-ray sensitive
slightly X-ray sensitive
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 + He
and H3+ + OH → OH+ + H + H2
– H3+ + S → SH+ + H2
Stäuber et al. 2005
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 tracer 4.9E+08 *
1669.1 2 → 1 *
NH 974.5 1 → 0 use? 4.8E+12
NH+ 1038.1 use? 7.9E+08
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
Molecules and Lines (Cont.)
FeH All very weak. Why observe?
SiH
PH CaHLiH
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 **
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 *
Objects and Strategy
1. 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 hr2. 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-mass1 intermediate-mass stars
To Do
1. Vary initial abundances and other parameters
2. Calculate antenna temperature for all lines
3. Select molecules
4. Select lines
5. Select objects from water KP list
6. Ancillary data (ground based observations)
