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GRAMS Modeling of Oxygen-Rich Dust around Red Supergiant and AGB Stars in the Large Magellanic Cloud. Benjamin Sargent Collaborators: Sundar Srinivasan , Dave Riebel , Martha Boyer, Margaret Meixner March 28, 2012 Space Telescope Science Institute. Image: Gordon & SAGE team

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Benjamin sargent

GRAMS Modeling of Oxygen-Rich Dust around Red Supergiant and AGB Stars in the Large Magellanic Cloud

Benjamin Sargent

Collaborators: SundarSrinivasan, Dave Riebel, Martha Boyer, Margaret Meixner

March 28, 2012

Space Telescope Science Institute

Image: Gordon & SAGE team

(Meixner et al. 2006)


Lifecycle of matter how much mass is lost from stars

Lifecycle of Matter: How much mass is lost from stars?

AGB Stars: O-rich and

C-rich dust produced

RSG Stars: O-rich only


Modeling evolved stars

Modeling Evolved Stars

  • Assume a spherical cow …

  • R-2 density drop-off from assumption of constant mass loss

  • Drawing not to scale!

  • Rout = 1000*Rmin assumption


Grams g rid of r ed supergiant and a gb m odel s

GRAMS: Grid of Red supergiant and AGB ModelS

  • GRAMS computed using 2Dust (Ueta & Meixner2003) radiative transfer modeling code

  • http://www.stsci.edu/science/2dust/grams_models.cgi

  • GRAMS  returns Mass Loss Rate, Luminosity, and Dust Chemistry


Color color diagram

Color-Color Diagram

  • O-rich models

  • C-rich models

  • O-rich AGBs

  • C-rich AGBs

  • Extreme AGBs

  • RSGs

  • O-rich (spec)

  • C-rich (spec)

From Sargent et al 2011

X-axis (K-[3.6]) is stellar color, Y-axis ([3.6]-[24]) is overall IR color


Comparison to other work

Comparison to Other Work

  • Generally, good agreement, except GRAMS MLRs disagree with G09 for low MLRs

  • GRAMS uses one dust type for all models; G09 used many dust types, but no dependence upon MLR, so dust type not behind factor x6 MLR discrepancy


O rich agb dust properties

O-rich AGB Dust Properties

  • SEDs: U, B, V, I from MCPS (Zaritsky et al 1997); J, H, Ks from 2MASS (Skrutskie et al 2006), IRAC and MIPS-24 from SAGE

  • Right, SED of oxygen-rich (O-rich) AGB star; 2Dust (Ueta & Meixner 2003) model of O-rich AGB (Sargent et al 2010)

  • But …


One dust type doesn t fit all

One Dust Type Doesn’t Fit All


Isolating dust emission

Isolating Dust Emission

  • SED is fit by GRAMS, star is subtracted

  • Measure centroid of features, continuum slope


Spitzer irs spectroscopic studies of agbs and rsgs

Spitzer-IRS Spectroscopic Studies of AGBs and RSGs

  • Average AGB 10μm feature centroid displaced to shorter λ‘s than RSGs’ (Sargent et al, in prep)

  • Similar discrepancy seen between Miras and non-Miras by Marengo et al (2001)


Rsg vs agb silicates

RSG vs AGB Silicates

  • Star-subtracted continuum slope relatively independent of 10 μm silicate feature centroid


Rsg vs agb silicates con t

RSG vs AGB Silicates, con’t

  • RSG shells have hotter dust, but if continuum slope were affecting centroid, hotter dust would mean shorter-wavelength centroids


Conclusions

Conclusions

  • NASA ADAP grant NNX11AB06G

  • GRAMS model grid useful for determining mass loss from AGB and RSG stars

  • Difference between AGB and RSG average 10 μm feature centroid. Different avg dust optical properties?

  • Silicate feature peak wavelength difference not due to temperature effect on continuum

  • Thank you!


References

Asplund, M., et al., 2004, A&A, 417, 751

Bekki, K., & Chiba, M., 2005, MNRAS, 356, 680

Dufour, R. J., et al., 1982, ApJ, 252, 461

Gautschy-Loidl, R., et al., 2004, A&A, 422, 289

Houck, J. R., et al., 2004, ApJS, 154, 18

Kučinskas, A., et al, 2005, A&A, 442, 281

Kučinskas, A., et al, 2006, A&A, 452, 1021

Marengo, M., et al., 2001, MNRAS, 324, 1117

Meixner, M., et al., 2006, AJ, 132, 2268

Ossenkopf, V., et al., 1992, A&A, 261, 567

Pégourié, B., 1988, A&A, 194, 335

Pei et al., 1999, ApJ, 522, 604

Sargent, B. A., et al., 2010, ApJ, 716, 878

Sargent, B. A., et al., 2011, ApJ, 728, 93

Schaefer, B. E., 2008, AJ, 135, 112

Skrutskie, M., et al, 2006, AJ, 131, 1163

Srinivasan, S., et al., 2009, AJ, 137, 4810

Srinivasan, S., et al., 2010, A&A, 524, A49

Srinivasan, S., et al., 2011, A&A, 532, A54

Szewczyk, O., et al., 2009, AJ, 138, 1661

Ueta, T., & Meixner, M., 2003, ApJ, 586, 1338

Zaritsky, D., Harris, J., & Thompson, I., 1997, AJ, 114, 1002

Zubko, V. G., et al., 1996, MNRAS, 282, 1321

References


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