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Credit: ESA/Herschel 160 µm, 250/350 µm, 500 µm Yancy Shirley Univ. of Arizona How do starless cores evolve within filaments ?
Credit: Herschel Gould Belt Team Image Credit: J. Kirk (modifications by V. Konyves) Arizona Gould Belt Starless Core Surveys Galloway-Sprietsma et al. 2022 NH2D Scibelli et al. 2024 iCOMs Seo et al. 2015, 2019 NH3, CCS, HCN, HCO+,HC7N Scibelli et al. 2020, 2021, 2023 iCOMs, 3D Dust models Ambrose et al. 2021 CH2DOH Andras-Letanovszky et al. in prep. HDCO, D2CO, CH2DOH, CH3OD Gruber et al. in prep. N2D+, NH2D, DNC Harrison et al. in prep. HCN Blue/Red asymmetry mapping Steffes et al. in prep. CH2DOH, oNH2D, iCOMs
Chemical Inheritance From Starless Phase Steffes et al. in prep. update of figure in Drozdovskaya et al. 2021 Starless Core Low-mass Protostar Comet Preliminary < ½ of sample observed to date
Credit: Herschel Gould Belt Team 160 µm, 250/350 µm, 500 µm Credit: NH3Seo et al. 2015; 1.2mm Scibelli et al. 2023 B10 – A Starless Core Evolution “Laboratory” NH3 1.2mm Dozen starless cores with no embedded protostars (1 Class II nearby) spanning ~0.3pc
Bayesian NH3 multi-component re-analysis Svoboda in prep.; Steffes et al. in prep. NestFit: Determines the number of velocity components and estimate their model parameters using Bayes factors computed with Nested Sampling Monte Carlo Maximum Likelihood vLSR
3D Dust Continuum Modeling Scibelli et al. 2023 •106 + model Plummer Spheroids • Simultaneously match mm intensity profiles and SED • Virial analysis uses n(r,q,f) Radius (AU) Density (cm-3) Dust Temperature (K)
Scibelli et al. 2023 Starless Core Virial Balance 2 W KE = W Grav + W ExtP + WDm+ WRad Support terms Compression terms Kinetic Energy Grav. Pot. Energy + External Pressure Unbound Bound
Chapman et al. 2011; Planck+ 2016; Ward-Thompson et al 2023; Scibelli et al. 2023 BUT What is Magnetic Field Contribition? 2WKE + W Mag = WGrav + WExtP + WDm+ WRad Support terms Compression terms Kinetic Energy Grav. Pot. Energy + External Pressure DBeff ~ 15 µG DBeff = (Bi2– Bo2)1/2 We don’t have accurate maps of B field strength Bsky ~ 13 -75 µGdepending on method Submm Pol.Optical/NIR Pol.
B10 Deuteration Survey of Organic Molecules Andras-Letanovszky et al. in prep.; Scibelli et al. 2020; Ambrose et al. 2021 •o/pH2CO •HDCO • 20,2 – 10,1 129 GHz • 21,1 – 10,1 134 GHz •pD2CO • 21,2 – 11,1 110 GHz •CH3OH-A/E •CH2DOH • 20,2 e0– 10,1 e0 89 GHz HDCO & D2CO trace streamer impacting disk Podio et al. 2024 100% Detection Rate HDCO D2CO H2CO
Extras Slides
Eulerian Derivation: McKee & Zweibel 1992; Krumholz 2017 Virial Theorem ½ d2I/dt2 = 2WK+ WB–WG–2WP–WDm-Wrad WK= Internal Kinetic Energy = ½ M (sv2)3D WG= Grav. Potential Energy = ⅗a GM2/R WP= External Surface Pressure = 4 pR3P0 Turbulent P0= r0sv2 WDm= ½ d/dt ∫r0r2vi dSi2 R2d2M/dt2 simple approx. If mass flowing across boundary can get: (1) ram pressure P0and (2) WD WB= ∫xiTij dSj-∫dij Tij dV ⅙(B2– B02) R3 simple approx. WB= Magnetic Energy (very difficult to measure) Support terms Compression terms
Search for Core Infall Seo et al. 2019 HCN 1-0 F=2-1 HCO+1-0 •Infall signatures rare (only 2/33 Taurus starless cores) • Doesn’t necessarily mean cores aren’t collapsing – could be excitation
Deuterium Fractionation in Starless Cores Zahorecz et al. 2017 Gas-phase deuteration: H3 ++ HD ↔H2D++ H2+ [232K] H2D++ H2CO → H2DCO+ + H2 H2DCO+ + e-→ HDCO Grain surface deuteration: Hydrogenation of CO ice CO +H/D →HCO /DCO +H/D →H2CO /HDCO +H/D →CH3O / CH2DO +H/D →CH3OH /CH2DOH Sipilä+19 Gas phase bottleneck @ 10K to CH3OH formation (Geppert+ 2006) Non-thermal desorption (3)
NH2D Chemical Model Comparison Galloway-Sprietsma et al. 2022 oNH2D survey of starless cores in L1251 [oNH2D]/[pNH3]
