Low mass star formation using high-J CO and O2 lines

PhD Colloquium, Leiden Observatory

Transcript

1. PhD Colloquium, March 4, 2013 Umut A.Yıldız Ewine van Dishoeck Lars Kristensen (CfA) and WISH & HOP Teams Leiden Observatory, The Netherlands Low-mass star formation using high-J CO and O2 lines Monday, March 4, 13
2. >>> Outline • Low-Mass Star-Formation • WISH & HOP • CO Survey of Low Mass YSOs • A case study: CO excitation in YSOs • O2 in NGC1333 IRAS4A Monday, March 4, 13
3. • Specific Aims: • Trace and quantify WARM gas by high-J CO observations which is better diagnostic of the energetic processes that shape these deeply embedded sources. • Previous studies observed cold gas and dust (as probed by low-J CO lines; J≤3) which include cloud emission. • Comparing the physical properties and evolution of a large sample of low-mass young stellar objects by using higher-J CO lines (J≥6). Aims • General Aim: • Understand formation of low-mass stars in the early phases • Study their physics and chemistry Monday, March 4, 13
4. Molecular Clouds Low  Mass  Star  Formation                  submm                                      IR                                        optical Deeply Embedded Phase - Class 0 & I T-tauri phase Planet forming disk Main-sequence star André, 2000 Monday, March 4, 13
5. • WARM GAS: • How much warm gas? Which location does it originate? • How is this gas heated: shocks vs. UV heating, or something else? • CO excitation: • What is the role of outflows and cavity walls vs protostellar envelope? • How does the CO abundance evolve as function of radius over the entire envelope? • How different are Class 0 and I YSOs? Tracing evolution by CO emission? • What is the abundance of O2 in a Class 0 protostar? Open  Questions? Monday, March 4, 13
6. • HIFI GTKP to study the physical and chemical structure of star- forming regions focussing on H2O and its related species • Both HIFI and PACS spectroscopy are used “HOP” Herschel  Oxygen  Project PI:  Paul  Goldsmith “WISH” Water  in  Star-­‐forming  regions   with  Herschel PI:  Ewine  van  Dishoeck • HIFI OTKP aims to search for the elusive O2 in dense star-forming clouds • Different type of sources targeted • Consider here one source: embedded Class 0 protostar NGC1333 IRAS 4A van Dishoeck et al. 2011, PASP Goldsmith et al. 2011, ApJ Monday, March 4, 13
7. A. Karska et al. 2010: APEX CHAMP+ high-J CO observations of L1527 and L483 7 Fig. 4. Top panel: CO 6-5 and CO 7-6 maps of L1527. Contour levels are 6σ, 12σ, 18σ etc. (σ(CO 6−5) = 1.5 K and σ(CO 7 − 6) = 4.1 K). Central position is marked with a X. Bottom panel: Spectral maps of L1527 in CO 6-5 (right) and CO 7-6 (left) transitions. Time Mass Prestellar Class 0 Class 1 Disks Intermediate- High-mass Low- ~80 sources ~80 sources (L. Kristensen) WISH  Sources Monday, March 4, 13
8. A. Karska et al. 2010: APEX CHAMP+ high-J CO observations of L1527 and L483 7 Fig. 4. Top panel: CO 6-5 and CO 7-6 maps of L1527. Contour levels are 6σ, 12σ, 18σ etc. (σ(CO 6−5) = 1.5 K and σ(CO 7 − 6) = 4.1 K). Central position is marked with a X. Bottom panel: Spectral maps of L1527 in CO 6-5 (right) and CO 7-6 (left) transitions. Time Mass Prestellar Class 0 Class 1 Disks Intermediate- High-mass Low- ~80 sources ~80 sources (L. Kristensen) WISH  Sources Monday, March 4, 13
9. pre-stellar cores YSO’s disks comets oceans life ... • CO is the 2nd most abundant molecule and Oxygen is the 3rd most abundant element • H2O and CO are complementary to each other. • High-J CO and H2O are natural filters of warm gas -unique probes of different physical regimes-. • CO abundance shows small variations • Main reservoir of oxygen -affects chemistry of many other species-. Why    CO  and  O2  ? Monday, March 4, 13
10. • Many CO lines are targeted with different Eup to probe range of temperatures. • Lower-J CO (Jup ≤3) transitions have been observed from ground-based telescopes. • But higher-J CO observations via APEX and HIFI are unique for warmer regions. Energy  Levels Rotational  Lines CO Energy [K] Monday, March 4, 13
11. • Many CO lines are targeted with different Eup to probe range of temperatures. • Lower-J CO (Jup ≤3) transitions have been observed from ground-based telescopes. • But higher-J CO observations via APEX and HIFI are unique for warmer regions. Energy  Levels Rotational  Lines CO Energy [K] Monday, March 4, 13
12. • Many CO lines are targeted with different Eup to probe range of temperatures. • Lower-J CO (Jup ≤3) transitions have been observed from ground-based telescopes. • But higher-J CO observations via APEX and HIFI are unique for warmer regions. Energy  Levels Rotational  Lines CO Energy [K] HIFI - 1151 GHz APEX - 691 GHz APEX - 806 GHz MAPS Monday, March 4, 13
13. • Herschel Space Observatory • 3.5 meter submm and far-IR telescope in space Observations • HIFI (PI: SRON) • Single-pixel heterodyne instrument • Covering 480−1910 GHz (157−625 µm) • Ultra-high spectral resolution (dv < 0.1 km/s), line profiles are resolved => kinematic information • APEX Atacama Pathfinder Experiment • 12 m telescope on Chajnantor, Chile • CHAMP+ • Efficient mapping capability • PI instrument of MPIfR/SRON-NOVA (Güsten et al. 2008; Kasemann et al., 2006) • 2 heterodyne receiver arrays, each 7 pixel detector elements • Simultaneously observe 620−720 GHz & 780−950 GHz 8’’ (~1900 AU), 9’’ (~2100 AU) at 240pc Monday, March 4, 13
14. CO  Survey  of  Low  Mass  YSOs >>> Evolution  via  excitation Excitation  Temperatures CO  ladder Evolution  via  outflow  forces Yıldız  et  al.,  submitted Yıldız  et  al.,  in  prep. Monday, March 4, 13
15. • Herschel-HIFI: single pointing observations (higher-J) • APEX-CHAMP+: maps of CO 6−5, 7−6, 13CO 6−5, and single pointings of C18O 6−5, 13CO 8−7 • JCMT-HARPB: maps (lower−J) CO 3−2, single CO 2−1 van  Kempen  et  al.  (2009a,b),  Yıldız  et  al.  (2010,  2012),   van  Dishoeck  et  al.  (2011),  Yıldız  et  al,  subm.,  in  prep. Survey  of  Low  Mass  YSOs 100 101 Lbol[L ] 10−1 100 101 Menv[M ] Class 0 Class I • 26 sources, 15 Class 0 and 11 Class I • Sources are selected from nearby Star- Forming Regions (davg=200 pc), Luminosity range (0.5−30 L⊙ ) Monday, March 4, 13
16. • Rich CO observations for 26 Class 0 & I sources • Unique collection of high quality CO data for constraining physical processes in an unprecedented manner • Evolution via all CO lines High  quality  CO  lines Class I 12CO 10-9 Class 0 Monday, March 4, 13
17. L1448MM IRAS2A IRAS4A IRAS4B L1527 Ced110IRS4 BHR71 IRAS15398 L483MM SMM1 SMM4 SMM3 L723MM B335 L1157 L1489 L1551IRS5 TMR1 HH46 DKCha GSS30IRS1 Elias29 0 20 40 60 80 100 Narrow/Broad (%) Narrow Broad Decomposing  12CO  10−9 Class 0 Class I • Median fraction 42% • Contributions are comparable • Careful with interpreting spectrally unresolved data (SPIRE, PACS) • Relative fraction of integrated intensity of narrow and broad components for each source Yıldız  et  al.,  subm.,  San  Jose  Garcia  et  al.  in  press Monday, March 4, 13
18. Rotational  Diagrams • Rotation Diagrams are to find excitation temperatures • Constructed for Class 0 and Class I sources • 12CO, 13CO, C18O (2−1 to 10−9) All in 20’’ beam E.g.; 12CO Class 0 sources 28 30 32 34 36 L1448mm 81 ± 10K IRAS2A 57 ± 7K IRAS4A 77 ± 9K IRAS4B 83 ± 11K L1527 62 ± 8K 28 30 32 34 36 Ced110IRS4 67 ± 12K BHR71 72 ± 13K IRAS15398 104 ± 16K L483mm 77 ± 10K SMM1 97 ± 12K 0 100 200 300 Eup [K] 28 30 32 34 36 ln(Nup /gup ) SMM4 71 ± 10K 0 100 200 300 SMM3 74 ± 9K 0 100 200 300 L723mm 71 ± 13K 0 100 200 300 B335 71 ± 9K 0 100 200 300 L1157 62 ± 8K Monday, March 4, 13
19. 0 1 2 3 4 5 6 7 # of sources 12CO Class 0 Class I 40 60 80 100 Tex[K] 0 1 2 3 4 5 6 7 # of sources 13CO • Median Rotation Temperatures • 12CO ~ 72K • 13CO ~ 45K • C18O ~ <35 K • Distribution of Class 0 and Class I sources • High-J C18O mainly upper limits Model  vs.  Observations Rotational  Diagrams 12CO 13CO Monday, March 4, 13
20. 40 50 60 70 80 90 100 110 120 Tex(12CO)[K] L1448mm IRAS2A IRAS4A IRAS4B L1527 Ced110IRS4 BHR71 IRAS15398 L483mm SMM1 SMM4 SMM3 L723mm B335 L1157 L1489 L1551IRS5 TMR1 TMC1A TMC1 HH46 DKCha GSS30IRS1 Elias29 OphIRS63 RNO91 Class 0 Class I 20 30 40 50 60 70 80 Tex(13CO)[K] L1448mm IRAS2A IRAS4A IRAS4B L1527 Ced110IRS4 BHR71 IRAS15398 L483mm SMM1 SMM4 SMM3 L723mm B335 L1157 L1489 L1551IRS5 TMR1 TMC1A TMC1 HH46 DKCha GSS30IRS1 Elias29 OphIRS63 100 101 Lbol[L ] 10 20 30 40 50 60 Tex(C18O)[K] L1448mm IRAS2A IRAS4A IRAS4B L1527 Ced110IRS4 BHR71 IRAS15398 L483mm SMM1 SMM4 SMM3 L723mm B335 L1157 L1489 L1551IRS5 TMR1 TMC1A TMC1 HH46 DKCha GSS30IRS1 Elias29 OphIRS63 • Tex is similar for increasing Lbol • No significant difference between Class 0 and Class I • No trend seen also for • Menv • n(1000AU) Rotational  Diagrams 12CO 13CO C18O Monday, March 4, 13
21. • CO line fluxes different sources • High Redshift Quasar • An Ultraluminous IR galaxy • MilkyWay (Galactic plane) • Orion Bar PDR • Two protostars • Protostars have CO excitation • similar a ULIRG, a PDR • different Milky Way, a Quasar CO  ladder • Normalized relative to 12CO 4−3 and 13CO 6−5 Van der Werf et al., 2010; Wright et al., 1991; Habart et al., 2010; Weiss et al., 2007 12CO 13CO    Yıldız  et  al.,  2012 Monday, March 4, 13
22. APEX-­‐CHAMP+  Maps 12CO 3−2 12CO 6−5 JCMT-­‐HARPB  Maps • Beam size 9’’, • CO 6−5 Eup~100 K • Beam size 15’’ • CO 3−2 Eup~30 K −100 −50 0 50 100 −100 −50 0 50 100 IRAS4A IRAS4B −40 −30 −20 −10 0 10 20 30 40 50 −50 −40 −30 −20 −10 0 10 20 30 40 IRAS2A −50 0 50 −50 0 50 L1527 −30 −20 −10 0 10 20 30 −30 −20 −10 0 10 20 30 Ced110IRS4 −40 −20 0 20 40 −40 −20 0 20 40 IRAS15398 −50 0 50 −50 0 50 L483mm −150 −100 −50 0 50 100 150 200 −200 −150 −100 −50 0 50 100 150 SMM1 SMM3 SMM4 −40 −20 0 20 40 −40 −20 0 20 40 L723mm −40 −20 0 20 40 −40 −20 0 20 40 L1489 −30 −20 −10 0 10 20 30 40 −30 −20 −10 0 10 20 30 40 TMR1 −40 −20 0 20 40 −40 −20 0 20 40 TMC1A −40 −20 0 20 40 −40 −20 0 20 40 TMC1 −40 −30 −20 −10 0 10 20 30 −40 −30 −20 −10 0 10 20 30 HH46 −60 −40 −20 0 20 40 60 −60 −40 −20 0 20 40 60 GSS30IRS1 −60 −40 −20 0 20 40 60 −60 −40 −20 0 20 40 60 Elias29 −40 −20 0 20 40 −40 −20 0 20 40 OphIRS63 −60 −40 −20 0 20 40 60 ∆α [Arcsec] −60 −40 −20 0 20 40 60 ∆δ [Arcsec] RNO91 −200 −150 −100 −50 0 50 100 150 200 −200 −150 −100 −50 0 50 100 150 200 BHR71 −40 −30 −20 −10 0 10 20 30 40 −40 −30 −20 −10 0 10 20 30 40 B335 −20 −10 0 10 20 −20 −10 0 10 20 DKCha −100 −50 0 50 100 −100 −50 0 50 100 IRAS4A IRAS4B −40 −30 −20 −10 0 10 20 30 40 50 −50 −40 −30 −20 −10 0 10 20 30 40 IRAS2A −50 0 50 −50 0 50 L1527 −30 −20 −10 0 10 20 30 −30 −20 −10 0 10 20 30 Ced110IRS4 −40 −20 0 20 40 −40 −20 0 20 40 IRAS15398 −50 0 50 −50 0 50 L483mm −150 −100 −50 0 50 100 150 200 −200 −150 −100 −50 0 50 100 150 SMM1 SMM3 SMM4 −40 −20 0 20 40 −40 −20 0 20 40 L723mm −40 −20 0 20 40 −40 −20 0 20 40 L1489 −30 −20 −10 0 10 20 30 40 −30 −20 −10 0 10 20 30 40 TMR1 −40 −20 0 20 40 −40 −20 0 20 40 TMC1A −40 −20 0 20 40 −40 −20 0 20 40 TMC1 −40 −30 −20 −10 0 10 20 30 −40 −30 −20 −10 0 10 20 30 HH46 −60 −40 −20 0 20 40 60 −60 −40 −20 0 20 40 60 GSS30IRS1 −60 −40 −20 0 20 40 60 −60 −40 −20 0 20 40 60 Elias29 −40 −20 0 20 40 −40 −20 0 20 40 OphIRS63 −60 −40 −20 0 20 40 60 ∆α [Arcsec] −60 −40 −20 0 20 40 60 ∆δ [Arcsec] RNO91 −200 −150 −100 −50 0 50 100 150 200 −200 −150 −100 −50 0 50 100 150 200 BHR71 −40 −30 −20 −10 0 10 20 30 40 −40 −30 −20 −10 0 10 20 30 40 B335 −20 −10 0 10 20 −20 −10 0 10 20 DKCha    Yıldız  et  al.,  in  prep. Monday, March 4, 13
23. • FCO => strength of an outflow • Class 0 have more powerful outflows than Class I Outflow  forces −5.5 −5.0 −4.5 −4.0 −3.5 −3.0 −2.5 log(FCO (6−5) [M km s−1 yr−1]) 0 1 2 3 4 5 # of sources Class 0 Class I log (FCO) # of sources 100 101 Lbol[L ] 10−6 10−5 10−4 10−3 FCO (6−5) [M km s−1 yr−1] 10−1 100 101 Menv[M ] 10−3 10−2 10−1 100 MCO (6−5) [M ] Monday, March 4, 13
24. >>> CO  excitation  in  YSOs Outflows Envelope UV  heated  Cavity  Walls Yıldız et al., 2010, A&A Yıldız et al., 2012, A&A :  a  case  study Monday, March 4, 13
25. Image Courtesy: R. Visser Tracing  components  with  CO Monday, March 4, 13
26. Outflows Probed by 12CO, H2O, OH, O I Broad Comp. 12CO low-J high-J Image Courtesy: R. Visser Tracing  components  with  CO Monday, March 4, 13
27. UV heated Cavity Walls 13CO, O I, C I 100K < Tgas < 1000K Outflows Probed by 12CO, H2O, OH, O I Broad Comp. 12CO 13 CO low-J high-J Image Courtesy: R. Visser Tracing  components  with  CO Monday, March 4, 13
28. Envelope Probed by C18O Narrow Component T < 200 K UV heated Cavity Walls 13CO, O I, C I 100K < Tgas < 1000K Outflows Probed by 12CO, H2O, OH, O I Broad Comp. 12CO 13 CO C18O low-J high-J Image Courtesy: R. Visser Tracing  components  with  CO Monday, March 4, 13
29. Envelope Probed by C18O Narrow Component T < 200 K UV heated Cavity Walls 13CO, O I, C I 100K < Tgas < 1000K Outflows Probed by 12CO, H2O, OH, O I Broad Comp. 12CO 13 CO C18O low-J high-J Image Courtesy: R. Visser Tracing  components  with  CO Monday, March 4, 13
30. • NGC 1333 IRAS 4A/4B protostars (d=235pc) • In the CO map, Spectrally resolved ⟹ dynamics of the region Spatially resolved ⟹ outflows • IRAS 4A outflow ⟹ initially N-S then bend over • IRAS 4B outflow N-S CO  6-­‐5  map  of  IRAS  4A/4B Yıldız et al., 2012, A&A 12CO Monday, March 4, 13
31. • NGC 1333 IRAS 4A/4B protostars (d=235pc) • In the CO map, Spectrally resolved ⟹ dynamics of the region Spatially resolved ⟹ outflows • IRAS 4A outflow ⟹ initially N-S then bend over • IRAS 4B outflow N-S CO  6-­‐5  map  of  IRAS  4A/4B Yıldız et al., 2012, A&A 12CO Monday, March 4, 13
32. • NGC 1333 IRAS 4A/4B protostars (d=235pc) • In the CO map, Spectrally resolved ⟹ dynamics of the region Spatially resolved ⟹ outflows • IRAS 4A outflow ⟹ initially N-S then bend over • IRAS 4B outflow N-S CO  6-­‐5  map  of  IRAS  4A/4B Yıldız et al., 2012, A&A 12CO Monday, March 4, 13
33. • Line of sight inclinations; • IRAS 4A ⟹ ~45−60o • IRAS 4B ⟹ ~15−30o Morphology  from  12CO  6-­‐5 Viewed from different angles 12CO Observed Monday, March 4, 13
34. • Line of sight inclinations; • IRAS 4A ⟹ ~45−60o • IRAS 4B ⟹ ~15−30o Morphology  from  12CO  6-­‐5 Viewed from different angles 12CO Observed Monday, March 4, 13
35. Extracting  Quantitative  Info Actual T for outflowing gas • Ratio indicates high temperature range 70−200 K IRAS4A IRAS4B 12CO T via CO 3-2/6-5 Radex/non-­‐LTE  slab  model Monday, March 4, 13
36. non-LTE 1D radiative transfer program RATRAN models run for IRAS 2A Yıldız et al., 2010, A&A Envelope Abundance Studies C18O Monday, March 4, 13
37. non-LTE 1D radiative transfer program RATRAN models run for IRAS 2A Yıldız et al., 2010, A&A Envelope Abundance Studies C18O Monday, March 4, 13
38. Yıldız et al., 2010, A&A Envelope Abundance Studies • Constant: cannot reproduce observed lines simultaneously C18O Monday, March 4, 13
39. Yıldız et al., 2010, A&A Envelope Abundance Studies • Constant: cannot reproduce observed lines simultaneously • Anti-jump: low-J OK but not higher-J C18O Monday, March 4, 13
40. Yıldız et al., 2010, A&A Envelope Abundance Studies • Constant: cannot reproduce observed lines simultaneously • Drop: Best fit to all data, Xin<X0 CO is transferred to other species - APEX is crucial for quantifying abundance • Anti-jump: low-J OK but not higher-J C18O Monday, March 4, 13
41. Fit to the data Model to the data Outflow Subtracted 13CO 6-5 source position IRAS4A IRAS4B • UV photons also heat the gas • 13CO 6−5 narrow emission can actually be produced in the envelope Use  C18O  model  to  predict  narrow  13CO Yıldız et al., 2012, A&A UV Heating of Cavity Walls 13CO Outflow Monday, March 4, 13
42. Fit to the data Model to the data Outflow Subtracted 13CO 6-5 source position IRAS4A IRAS4B • UV photons also heat the gas • 13CO 6−5 narrow emission can actually be produced in the envelope Use  C18O  model  to  predict  narrow  13CO Yıldız et al., 2012, A&A UV Heating of Cavity Walls 13CO Outflow Monday, March 4, 13
43. Fit to the data Model to the data Outflow Subtracted IRAS4A IRAS4B • UV photons also heat the gas • 13CO 6−5 narrow emission can actually be produced in the envelope Use  C18O  model  to  predict  narrow  13CO Yıldız et al., 2012, A&A UV Heating of Cavity Walls 13CO Outflow Monday, March 4, 13
44. −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) IRAS 4A IRAS 4B 13CO 6 − 5 0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 Tmb dV • Note that Intensity Scale changes IRAS  4B IRAS  4A Basic Math with 13CO 6−5 (Observed Spectra • 13CO 6−5 reveal the first direct observational evidence for the UV heated gas distribution UV Heating of Cavity Walls 13CO Monday, March 4, 13
45. −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) IRAS 4A IRAS 4B 13CO 6 − 5 0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 Tmb dV • Note that Intensity Scale changes IRAS  4B IRAS  4A −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Tmb dV Basic Math with 13CO 6−5 (Observed Spectra − Outflow • 13CO 6−5 reveal the first direct observational evidence for the UV heated gas distribution UV Heating of Cavity Walls 13CO Monday, March 4, 13
46. −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) IRAS 4A IRAS 4B 13CO 6 − 5 0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 Tmb dV • Note that Intensity Scale changes IRAS  4B IRAS  4A −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Tmb dV −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 Tmb dV Basic Math with 13CO 6−5 (Observed Spectra − Outflow − Envelope Emission) • 13CO 6−5 reveal the first direct observational evidence for the UV heated gas distribution UV Heating of Cavity Walls 13CO Monday, March 4, 13
47. −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) IRAS 4A IRAS 4B 13CO 6 − 5 0.0 1.5 3.0 4.5 6.0 7.5 9.0 10.5 12.0 Tmb dV • Note that Intensity Scale changes IRAS  4B IRAS  4A −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Tmb dV −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 Tmb dV −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) UV-Heated Gas 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Tmb dV Basic Math with 13CO 6−5 (Observed Spectra − Outflow − Envelope Emission) = UV heated gas • 13CO 6−5 reveal the first direct observational evidence for the UV heated gas distribution UV Heating of Cavity Walls 13CO Monday, March 4, 13
48. • For IRAS 4A, the mass of the UV- heated gas is at least comparable (even higher) to the mass of the outflow. But still only a few % of the total mass Mtotal Envelope Mcones Envelope Moutflow 12CO 6-5 MUV 13CO 6-5 IRAS 4A 5.0 1.5 3.7x10-3 1.7x10-2 IRAS 4B 3.1 0.9 1.0x10-3 ... −10 0 10 20 30 40 ∆α (Arcsec) −30 −20 −10 0 10 20 ∆δ (Arcsec) UV-Heated Gas 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Tmb dV Quantifying  UV  Heating (masses in M⊙ ) 13CO Monday, March 4, 13
49. >>> O2  in  NGC1333  IRAS  4A Tentative  Detection  of  O2 O2  abundance  in  a  protostar Yıldız  et  al.,  to  be  submitted “HOP” Monday, March 4, 13
50. O2  in  NGC1333  IRAS  4A 487  GHz            7.7  hours  int.  time!!! • rms  =  1.3  mK • Tmb  =  4.6  mK •Binary  Class  0  protostar   with  2’’  separation •Lbol  =  9.1  Lo •HIFI  beam  44’’ •Vlsr  =  7.0  km/s O2 •Blue  =>  8.0  km/s •Extended  cloud •Red  =>  7.0  km/s •Protostar Monday, March 4, 13
51. O2  in  NGC1333  IRAS  4A 487  GHz            7.7  hours  int.  time!!! • rms  =  1.3  mK • Tmb  =  4.6  mK •Binary  Class  0  protostar   with  2’’  separation •Lbol  =  9.1  Lo •HIFI  beam  44’’ •Vlsr  =  7.0  km/s O2 •Blue  =>  8.0  km/s •Extended  cloud •Red  =>  7.0  km/s •Protostar Monday, March 4, 13
52. •Comparison  with   optically  thin  C18O •Data  convolved  to  44’’   beam •Note    O2  vs.  low-­‐J  CO   line  at  extended  cloud   velocity O2  together  with  C18O   O2 Monday, March 4, 13
53. •Comparison  with   optically  thin  C18O •Data  convolved  to  44’’   beam •Note    O2  vs.  low-­‐J  CO   line  at  extended  cloud   velocity O2  together  with  C18O   O2 Monday, March 4, 13
54. •Comparison  with   optically  thin  C18O •Data  convolved  to  44’’   beam •Note    O2  vs.  low-­‐J  CO   line  at  extended  cloud   velocity O2  together  with  C18O   O2 Monday, March 4, 13
55. •Comparison  with   optically  thin  C18O •Data  convolved  to  44’’   beam •Note    O2  vs.  low-­‐J  CO   line  at  extended  cloud   velocity O2  together  with  C18O   O2 Monday, March 4, 13
56. Simple  Slab  Analysis •nH  (44’’)  =  3.6x105  cm-­‐3 IRAS4A X (7 km s-1) X (8 km s-1) O2 33−12 <5.7x10-9 ~2x10-8 C18O ~4.5x10-7 O2 Monday, March 4, 13
57. Simple  Slab  Analysis •nH  (44’’)  =  3.6x105  cm-­‐3 IRAS4A X (7 km s-1) X (8 km s-1) O2 33−12 <5.7x10-9 ~2x10-8 C18O ~4.5x10-7 [CO/C18O]=550,  [CO/H2]=10-­‐4  (Wilson  &  Rood  1994) O2 Monday, March 4, 13
58. Model  vs.  Observations •Drop  Abundance  Profile  for  O2   (Assumes  constant  O2  over  CO   abundance) •Xin  =  2.1  x  10-­‐7 •XD  =  2.1  x  10-­‐8 •X0  =  5.0  x  10-­‐7 O2 44’’ Ratran Monday, March 4, 13
59. Other  observations  of  O2 •Gas-­‐phase  chemistry  predictions  X(O2)  ~  7x10-­‐5  (Woodall  et  al.  2007) •Detection  in  cloud  implies  10-­‐8  O2/H2,  consistent  with  PDR  models   (Hollenbach  et  al.  2009) •Non-­‐detection  in  envelope  implies  <5.7x10-­‐9  O2/H2.  Full  chemical   model  by  Acharyya  requires  long  cold  pre-­‐stellar  phase  to  convert   O  to  H2O  ice  rather  than  O2 •In  Herschel-­‐HOP  KP; •2  Detections:  Orion            X(O2)  ~  10-­‐6    &    ρ  Oph  A            X(O2)  ~  5x10-­‐8 •Non-­‐detection  6  sources  set  upper  limit  =>  X(O2)  <  10-­‐8 Goldsmith  et  al.  2011,  Liseau  et  al.  2012,  Yıldız  et  al.  in  prep. O2 Monday, March 4, 13
60. Other  observations  of  O2 •Gas-­‐phase  chemistry  predictions  X(O2)  ~  7x10-­‐5  (Woodall  et  al.  2007) •Detection  in  cloud  implies  10-­‐8  O2/H2,  consistent  with  PDR  models   (Hollenbach  et  al.  2009) •Non-­‐detection  in  envelope  implies  <5.7x10-­‐9  O2/H2.  Full  chemical   model  by  Acharyya  requires  long  cold  pre-­‐stellar  phase  to  convert   O  to  H2O  ice  rather  than  O2 •In  Herschel-­‐HOP  KP; •2  Detections:  Orion            X(O2)  ~  10-­‐6    &    ρ  Oph  A            X(O2)  ~  5x10-­‐8 •Non-­‐detection  6  sources  set  upper  limit  =>  X(O2)  <  10-­‐8 Goldsmith  et  al.  2011,  Liseau  et  al.  2012,  Yıldız  et  al.  in  prep. O2 IRAS  4A  abundance  is  the  lowest  limit  found  to  date  =>  X(O2)<5.7x10-­‐9     Monday, March 4, 13
61. Take-home Messages • APEX and Herschel-HIFI open new era of high-J CO observations for tracing warm gas • In the 12CO maps, the lines are spectrally resolved and provide crucial information regarding the dynamics of the region • Broad CO ⟹ outflow • Narrow CO ⟹ warm envelope and UV heated • Tkin up to 10−9 traces gas from 100−250 K. • 13CO 6−5 reveal the first direct observational evidence for the UV heated gas distribution • Isotopologues are crucial for estimating the abundance. Together with high-J observations of C18O, drop abundance profile fits for the observed transitions, leading to Xin<X0 • O2 abundance in a protostar is as low as X(O2) < 5.7x10-9 “HOP” Monday, March 4, 13