250 likes | 332 Views
August 12 th , 2011. A nna M iotello. Graduated in Physics at University of Milan, Italy (2011). New results on the giant dark silhouette disk dd114-426 in the Orion Nebula. miotello@stsci.edu. Doing Master’s degree in Astrophysics at University of Milan, Italy. Anna Miotello
E N D
August 12th, 2011 Anna Miotello Graduated in Physics at University of Milan, Italy (2011) New results on the giant dark silhouette disk dd114-426 in the Orion Nebula. miotello@stsci.edu Doing Master’s degree in Astrophysics at University of Milan, Italy Anna Miotello Massimo Robberto
Anno accademico 2009-2010 Anna Miotello 114-426 NASA, ESA, M. Robberto (STScI/ESA), HST Orion Treasury Project Team.
Anna Miotello Massimo Robberto Why is 114-426 important ? miotello@stsci.edu (Ricci et al. 2008) The presence of disks with and without evidence of photoevaporation in the same cluster provides a unique opportunity of understanding how environmental factors may affect the path to planet formation. August 12th, 2011
Anna Miotello Observations Massimo Robberto HST images N 1000AU W ACS ACS ACS ACS ACS WFPC2 miotello@stsci.edu F658N F775W F435W F555W F820LP F336W Hα I U B z V August 12th, 2011
Anna Miotello Geometry Massimo Robberto Disk Structure Multiple asymmetry ACS • Lobe dimensions • Lobe positions ~44° • Stretched disk’s top miotello@stsci.edu F820LP (Atanassiu L. F. D.) August 12th, 2011
Anna Miotello Geometry Massimo Robberto N Disk Structure W 746 AU 1117.8 AU ★ miotello@stsci.edu 210 AU F658N – F850LP August 12th, 2011
Anna Miotello Geometry Massimo Robberto 114-426 in its Environment 121-434 EUV flux from θ1C ~ 0.01 pc ~ 0.03 pc miotello@stsci.edu 117-421 August 12th, 2011
Anna Miotello Geometry Massimo Robberto 114-426 in its Environment miotello@stsci.edu (Bally et al. 2000) August 12th, 2011
Anna Miotello Discussion Massimo Robberto Photoevaporation FUV photons EUV photons ( 6 eV ≤ hν ≤ 13.6 eV ) ( hν ≥ 13.6 eV ) • Create a PDR at the disk surface with • T ~ 100 ÷ 1000 K • Are absorbed early on at a IF in the photoevaporated wind that escapes radially, being ionized and heated to T ~ 10 000 K • Are not absorbed by atomic hydrogen and easily penetrate to the disk surface miotello@stsci.edu Even in the core of the Trapezium Cluster, disk photoevaporation is normally supported by FUV photons (Johnstone et al. 1998 ) August 12th, 2011
Anna Miotello Results Massimo Robberto Mass loss (Adams et al. 2004) Observations • Chemical composition • FUV flux coming from the Trapezium and scattered by the nebular wall miotello@stsci.edu ~ 1 August 12th, 2011
Anna Miotello Particle sizing Massimo Robberto Ypixel 93 92 91 90 89 88 87 86 85 84 83 82 81 80 miotello@stsci.edu Xpixel 49 August 12th, 2011
Anna Miotello Particle sizing Massimo Robberto Ypixel Pixel Mean Radius Refraction index Pixel [49:93] : a = 0.20 μm m = 1.3 + i0.01 Pixel [49:92] : a = 0.21 μm m = 1.3 + i0.01 Pixel [49:91] : a = 0.36 μm m = 1.3 + i0.01 Pixel [49:90] : a = 0.42 μm m = 1.3 + i0.01 Pixel [49:89] : a = 0.44 μm m = 1.3 + i0.01 Pixel [49:88] : a = 0.48 μm m = 1.3 + i0.01 Pixel [49:87] : a = 0.53 μm m = 1.3 + i0.01 Pixel [49:86] : a = 0.51 μm m = 1.3 + i0.01 Pixel [49:85] : a = 0.53 μm m = 1.3 + i0.01 Pixel [49:84] : a = 0.55 μm m = 1.3 + i0.01 Pixel [49:83] : a = 0.58 μm m = 1.3 + i0.01 Pixel [49:82] : a = 0.59 μm m = 1.3 + i0.01 Pixel [49:81] : a = 0.60 μm m = 1.3 + i0.01 Pixel [49:80] : a = 0.60 μm m = 1.3 + i0.01 93 92 91 90 89 88 87 86 85 miotello@stsci.edu 84 83 82 81 80 Xpixel 49 August 12th, 2011
Anna Miotello Results Massimo Robberto Mass loss (Adams et al. 2004) Disk Mass (McCaughrean et al. 1998; Mann & Williams 2010) miotello@stsci.edu Time scale for the mass loss of the disk August 12th, 2011
Anna Miotello Massimo Robberto miotello@stsci.edu August 12th, 2011
August 12th, 2011 Ancillary slides miotello@stsci.edu
Anna Miotello Massimo Robberto Sections • Observations • Geometry of the disk • Dust particles sizing miotello@stsci.edu • Results and Comments • Conclusions August 12th, 2011
Anna Miotello Massimo Robberto Why is 114-426 important ? Previous works • The largest in ON: D ~ 1000AU. • (McCaughrean et al. 1998) • Undetected central star: Av ≥ 60 mag of extinction. (McCaughrean et al. 1998) • Estimation for the disk mass: • (McCaughrean et al. 1998; Mann & Williams 2010) miotello@stsci.edu • Properties of disk grains: evidence of chromatic extinction and grain growth (1.9 μm ≤ d ≤ 4 μm).(Throop et al. 2001; Shuping et al. 2003) August 12th, 2011
Anna Miotello Geometry Massimo Robberto Disk Structure Tail miotello@stsci.edu August 12th, 2011
Anna Miotello Particle sizing Massimo Robberto Extinction curve Qext Radius of the spherical particle miotello@stsci.edu x n = 1.3 August 12th, 2011
Anna Miotello Particle sizing Massimo Robberto Extinction curve Radius of the spherical particle Qext Qmax miotello@stsci.edu x Observational data : August 12th, 2011
Anna Miotello Massimo Robberto miotello@stsci.edu August 12th, 2011
Academicand personal career Graduated in Physics at University of Milan, Italy (2011) Doing Master’s degree in Astrophysics at University of Milan, Italy miotello@stsci.edu Working on 114-426 protoplanetary disk in the Orion Nebula with Dr. Massimo Robberto (SASP 2011 - STScI) Anna Miotello
Anna Miotello Massimo Robberto miotello@stsci.edu August 12th, 2011
Anna Miotello Massimo Robberto miotello@stsci.edu August 12th, 2011
Anna Miotello Massimo Robberto miotello@stsci.edu August 12th, 2011