Building on New Worlds, New Horizons March 7 – 10, 2011 Tracing Molecular Material from Circumstellar Envelopes into the Diffuse ISM L.M. Ziurys J.L. Dodd L.N. Zack 1.0 N.J.Woolf 0.8 University of Arizona 0.6 Arizona Radio Observatory (K) * R T 0.4 Steward Observatory 0.2 0.0 rizona 3 A 143.0 143.2 143.4 143.6 143.8 144.0x10 Frequency (MHz) Radio Observatory Building on New Worlds, New Horizons March 7 – 10, 2011 The Success of Molecular Astrophysics • Molecular Astrophysics: 37 Years of Investigation ⇒ Universe in truly MOLECULAR in nature • Molecular Gas is Widespread in the Galaxy and in External Galaxies CO: J = 1 – 0 CfA survey • 50% of matter in inner 10 kpc of Galaxy is MOLECULAR 6 • Molecular clouds largest well-defined objects in Galaxy (1 - 10 M¤) • COLD and DENSE by interstellar standards: T ~ 10 – 100 K; n ~ 103 - 107 cm-3 • Unique tracers of chemical/physical conditions in cold, dense gas ⇒ New window on astronomical sources ⇒ Critical to understanding of Star and Solar System Formation, Evolved Stars, Galactic Structure, ISM in External Galaxies, etc. Building on New Worlds, New Horizons March 7 – 10, 2011 But is there more to this Story ?? • Elements and Molecules e ⇒ originate in dying stars • Molecular material cycled through other phases before reaching dense clouds, protostellar disks • Are these phases linked ? Building on New Worlds, New Horizons March 7 – 10, 2011 Following Molecular Matter with Millimeter/Sub-mm Astronomy • Using ARO Facilities: ⇒ Sub-mm Telescope (SMT) on Mt. Graham, AZ ⇒ ARO 12 m at Kitt Peak • Studies conducted with ALMA-type Receivers ⇒ Sideband-Separating SIS Mixers • Offer the ULTIMATE in Sensitivity and Stability • Receivers: Bands 3, 6, and 9 (3 mm, 1 mm and 0.4 mm) Band 8 Receiver: ARO 12 m ARO SMT In Development (Balanced, SSB Mixers with AlN) Arizona ARO Radio Observatory Band 9 Receiver Building on New Worlds, New Horizons March 7 – 10, 2011 Circumstellar Origins PLANETARY NEBULA PROTO-PLANETARY 3.40 — Stellar envelope completely NEBULA (PPN) detached HELIX Nucleosynthesis stops • Stars with ~ 1 - 8 M¤ : Most stars CRL2688 ⇒ Follow common evolutionary To ASYMPTOTIC GIANT White BRANCH (AGB) 3.25 — He & H Shell sequence: GIANT BRANCHES Dwarf Burning Envelope • Deplete hydrogen in core IRC+10216 • Burn H in a shell around core Log (L) H Shell Triple α-Process ⇒ Enter Red Giant Branch 3.10 — Burning He Core • Burn, then deplete Helium in core Burning • Burn He and H in shells H Shell Narrows RED ⇒ Asymptotic Giant Branch 2.95 — GIANT BRANCH (AGB) MAIN SEQUENCE • Significant Mass Loss occurs Hydrogen Core on Giant Branches ( ~ 0.5 M Burning First Dredge-up: ¤ 2.80 — Sun Surface Abundances Change remains for star) 4.30 4.15 4.00 3.85 3.60 Log (T ) ⇒ Supplies 80% of material in ISM e Building on New Worlds, New Horizons March 7 – 10, 2011 • Mass loss creates Circumstellar Envelope • Most Stars: O > C (Red giants, supergiants, some AGB) • Dredge-up events on AGB can create “carbon stars” with C > O • Both O-rich and C-rich circumstellar shells of gas and dust UV Circumstellar Envelope Dust Shell Acceleration Zone T ~ 25 K UV 105 cm-3 R1 R* Star T ~ 1000 K -1 UV Vexp ~ 15 km s 1010 cm-3 12 13 14 15 16 17 18 19 Log r (cm) • Large T and n Gradients in stellar envelopes Based on studies • LTE chemistry near stellar photosphere (T ~ 1000 K) of one object: • UV induced photochemistry at outer shell edges IRC+10216 • C - Rich Envelopes have UNIQUE Carbon-Based Chemistry Building on New Worlds, New Horizons March 7 – 10, 2011 MOLECULAR INVENTORY of C-RICH CIRCUMSTELLAR SHELLS CO CCH HC3N CCS SiCN MgNC CS C3H HC5N C3S SiC MgCN CN C O HC N C N AlNC 3 7 3 SiC2 HCN C H HC N C N KCN 4 9 5 SiC3 HCCH C H CH CN HC N NaCN 5 2 4 SiC4 HNC C6H H2C4 c-C3H2 H2CS CP - H2CCH2 C7H H2C6 CH3CN C4H CCP - CH4 C8H C2 HC2N C6H HCP - H2CO c-C3H C3 HCCNC C8H PN - CH3CCH CH2CHCN C5 C5N PH3 57 C-Bearing Molecules SiH4 SiO KCl NaCl NH3 (5 with phosphorus) SiN SiS AlF AlCl H2S Building on New Worlds, New Horizons March 7 – 10, 2011 And What About Oxygen-Rich Circumstellar Gas ? • Comparative Spectral Line Survey (Band 6: 215 – 285 GHz) ⇒ C-rich envelope IRC+10216 vs. O-rich envelope VY Canis Majoris (Tenenbaum et al. 2010) HST Image • VY CMa: Massive Supergiant (> 20 M¤) 5 • Most luminous IR source in the sky ~ 10 L¤ -4 -1 • HIGH Mass Loss Rate ~ 2 x 10 M¤ yr • At distance of 1.5 kpc • Source of OH, H2O, SiO masers 10,000 AU or 10″ Most sensitive survey to date: noise level ~ 5 mK Building on New Worlds, New Horizons March 7 – 10, 2011 Survey Results VY CMa • IRC+10216: - 720 lines total - 124 unidentified • VY Canis Majoris: - 131 lines total IRC+10216 - 14 unidentified OH NH3 NO CO H2S SiS CN SO2 SiO CS SO PN • C4H, SiC2 and NaCN dominate IRC+10216 spectrum HCN H2O NaCl • VY CMa spectrum dominated by SO2, SiO, SiS HNC PO NS • VY CMa surprises: New molecules & unusual line HCO+ AlO AlOH shapes Building on New Worlds, New Horizons March 7 – 10, 2011 CNT HCN: J = 8→7 H S 2 709 GHz .. .. ARO SMT. .. .. Arc II Arc I 5" Ziurys et al. 2009 Velocity componentsNML Cygnus: trace 1 mm different survey episodes at SMT (Dodd of mass et al.)loss Building on New Worlds, New Horizons March 7 – 10, 2011 From Circumstellar Shells to Planetary Nebulae • AGB stars evolve into planetary nebulae (PNe) • Central star becomes white dwarf: HOT (T ~ 100,000 K) UV emitter • Most of original stellar mass flows into ISM on timescales of 10,000 yrs. • Fate of Molecular Circumstellar Shell ? ⇒ Survey of Middle-Aged to Old PNe HCOHCO+(3+(3→→2) 2) (Dumbbell, M2-48, K4-47, Ring, etc.) ~ 1 ′ CS(5→4) CS(2CS(2→→1)1) Red Spider 1600 yrs. Ring Nebula 7000 yrs. Building on New Worlds, New Horizons March 7 – 10, 2011 The Helix Nebula at 12,000 yrs. + HCOH2CO: (2J 12= →1 1→11 )0 0.06 ~ 30 arcmin. 0.030 H CO 0.04 (125, 185) (-15, 270) (-120, 240) 0.010 (130, -180) 2 JKaKc= 211-110 0.015 0.005 0.03 0.02 * (K) * (K) * (K) R R R T T T 0.000 0.000 0.00 0.00 H2CO 0.02 JKaKc= 212-111 -80 -24 32 -80 -24 32 -80 -24 32 0.01 V V V LSR (km/s) LSR (km/s) LSR (km/s) 0.00 0.12 0.075 (390, -30) (-372, 0) 0.09 + 0.016 HCO J= 3-2 0.050 0.06 (K) 0.008 * * (K) * (K) R A R T T / T 0.000 0.025 0.03 * R T 0.000 0.00 0.08 HCO+ J= 1-0 -80 -24 32 -80 -24 32 0.04 V (km/s) V LSR LSR (km/s) 0.03 0.00 0.075 0.030 (130, -180) (-240, -100) (-300, -200) 0.02 0.6 CO 0.050 J= 1-0 • CO: J = 2-1 map of Young et al. 19990.015 * (K) * (K) * (K) R 0.01 R 0.3 R T T 0.025 T 0.000 0.0 0.00 0.000 -80 -24 32 -80 -24 32 -80 -24 32 -80 -24 32 VLSR(km/s) V (km/s) V (km/s) V (km/s) Zack & Ziurys 2011 LSR LSR LSR Y-scale: T *(K) + Velocity components tracedR in CO, HCO , H2CO Building on New Worlds, New Horizons March 7 – 10, 2011 Molecule Survival in Old Planetary Nebula + • In addition to CO, H2CO and HCO : HCN, HNC, CN seen in Helix (Bachiller 1997) ⇒ CCH and C3H2 in the Helix ⇒ Observed with ARO 12 m (Tenenbaum et al. 2009) 5 -3 • H2CO lines indicate n ~ 3 x 10 cm ⇒ MOLECULES SURVIVING in SELF-SHIELDING CLUMPS (Howe et al. 1994; Redman et al. 2003) • Start with 1- 8 M Star Helix ¤ • At end: 0.4 – 0.7 M¤ in White Dwarf • <0.1 M¤ in ionized gas Spitzer Image • Left with 0.2 – 7.2 M¤ Building on New Worlds, New Horizons March 7 – 10, 2011 PNe Ejecta Into Diffuse Clouds • Planetary Nebulae disperse into diffuse ISM • Fate of the surviving molecular gas ? • Observations towards Diffuse Clouds (Liszt and Lucas; Liszt et al; Maier et al) Molecule Helix Nebula Diffuse Cloudsa) -7 -9 H2CO 1 x10 4 x 10 -6 -8 C2H 1 x10 3 x10 -8 -9 c-C3H2 1 x 10 1 x10 CO 9 x 10-4 3 x10-6 CN 3 x 10-6 2 x10-8 • Diffuse Clouds and Planetary Nebulae similar set of molecules HCN 5 x 10-7 3 x10-9 • Molecules cannot be accounted for by in-situ gas-phase formation (Snow -7 -10 & McCallHNC 2006) 3 x10 6 x10 + -7 -9 ⇒ HCORemnant molecules2 x10 from planetary2 x10 nebulae ⇒a) From Origin Liszt ofet al.Diffuse (2006) Interstellar Bands ?? Building on New Worlds, New Horizons March 7 – 10, 2011 Contribution of Laboratory Spectroscopy • And what about the U-lines ? • How are molecular lines assigned in first place ? ⇒ Contribution of Laboratory Astrophysics ⇒ High-resolution gas-phase spectroscopy • Different techniques ⇒ mm/submm direct absorption ⇒ velocity modulation (selective detection of ions) ⇒ Fourier transform microwave (FTMW) spectroscopy • NOT commercially available • Synthesizing the molecules ⇒ DC/AC discharge, laser ablation, supersonic jet nozzle, Broida-type oven • Often crash-and-burn chemistry Building on New Worlds, New Horizons March 7 – 10, 2011 FeCN (X 4Δ ): J = 50.5 51.5 FeCN: A Case Study i Ω = 7/2 • Metal cyanides abundant in IRC+10216 Flory & Ziurys • FeCN a likely species • 10 years of laboratory effort...Fe(CO) 5 412700 412730 412760 4 Ω = 5/2 • Spectra suggested Δi ground state e f 6 • Theory predicted Δi ground electronic state • FTMW spectrum proved this beyond doubt 4 418960 418990 419020 FeCN (X Di): W = 7/2 Ω = 3/2 e J = 4.5 3.5 New f F = 5.5 4.5 F = 4.5 3.5 Molecule F = 3.5 2.5 Source: 421620 421650 421680 421710 Laser Ω = 1/2 Ablation/ e f DC discharge 424140 424170 424200 424230 424260 36099.9 36100.6 36101.3 Frequency (MHz) Frequency (MHz) Building on New Worlds, New Horizons March 7 – 10, 2011 High Top View B Voltage Solenoid Valve + – E Pulse δ + Driver 0 ν D S C 1 A S PIN LNA 3 Switch S2 Mixer Coupler 30 dB ν0 ν0 S3 LPF 4-40 GHz S4 TTL Pulse Sequence Computer A/D + δ Fourier Transform Microwave Spectrometer S4 0-50 dB Ziurys Lab Building on New Worlds, New Horizons March 7 – 10, 2011 Laser: Nd:YAG (Continuum Surelite I-10) Lucy, DeWayne, andSecond Ming harmonic (532 nm) Building on New Worlds, New