Stardust review astrophysical grains in stellar winds the ism debris disks and comets
Download
1 / 40

Stardust Review: Astrophysical Grains in Stellar Winds, the ISM, Debris Disks, and Comets - PowerPoint PPT Presentation


  • 97 Views
  • Uploaded on

Stardust Review: Astrophysical Grains in Stellar Winds, the ISM, Debris Disks, and Comets. R. D. Gehrz Department of Astronomy, University of Minnesota. Outline. Stardust and stellar evolution Infrared spectra and the properties of stardust Stardust and nova winds

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Stardust Review: Astrophysical Grains in Stellar Winds, the ISM, Debris Disks, and Comets' - lyndon


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Stardust review astrophysical grains in stellar winds the ism debris disks and comets

Stardust Review: Astrophysical Grains in Stellar Winds, the ISM, Debris Disks, and Comets

R. D. Gehrz

Department of Astronomy, University of Minnesota

R. D. Gehrz


Outline ISM, Debris Disks, and Comets

  • Stardust and stellar evolution

  • Infrared spectra and the properties of stardust

  • Stardust and nova winds

  • Grains in the ISM, debris disks and the Solar System

  • Conclusions

  • Appendix A: Gas Phase Abundances in Nova Ejecta

R. D. Gehrz


Stardust and stellar evolution

Stardust and Stellar Evolution ISM, Debris Disks, and Comets

R. D. Gehrz


IR Spectra of Dust Grains: Molecular Structure ISM, Debris Disks, and Comets

  • Silicates: SiO2 bond stretching and bending

  • vibrational mode emission at 10 m and 20 m

  • Silicon Carbide: SiC stretching vibrational mode

  • emission at 11.3 m

  • Carbon and iron: Smooth emissivity

  • Hydrocarbons (HAC and PAH): C-H stretch at 3.3 m and

  • other stretching modes at longer wavelengths

R. D. Gehrz


IR Spectra of Dust Grains: Mineralogy ISM, Debris Disks, and Comets

  • Amorphous grains grow stochastically at low temperatures

  • and have featureless emission features

  • Crystalline grains are annealed at high temperatures and

  • their emission features have fine structure

  • The amorphous/crystalline transition occurs at ~1000K

Amorphous Silicate

F. J. Molster et al., A&A, 366, 923 (2001)

C. Jäger et al., A&A, 408, 293 (2003)

R. D. Gehrz


IR Spectra of Amorphous and Crystalline Grains ISM, Debris Disks, and Comets

L. Piovan, R. Tantalo , & C. Chiosi, A&A,408, 559 (2003)

R. D. Gehrz


Silicates and SiC Grains in Stellar Winds ISM, Debris Disks, and Comets

Data from Gehrz et al. 1984, ApJ, 281, 303

R. D. Gehrz


A Classical Nova Explosion: Accretion followed by a TNR ISM, Debris Disks, and Comets

R. D. Gehrz


Ir radio development phases

IR/Radio Development Phases ISM, Debris Disks, and Comets

  • The luminosity of the outburst fireball is Lo LEdd

  • c measures nH and the ejected ionized gas mass Mgas during the free-free expansion phase

  • Lo LEdd = LIR for optically thick dust shells  Lo = constant for a long time

Fireball Expansion Phase

Free-Free Expansion Phase

Coronal Phase in ONeMg Novae

Dust Cocoon Phase in CO Novae

 in m

R. D. Gehrz (1988, 1990)

R. D. Gehrz


Dust condensation in co novae

Dust Condensation in CO Novae ISM, Debris Disks, and Comets

Dust Formation in NQ Vul

  • Tc 1000 K

  • , where Vo is the

  • outflow velocity

Visual Transition

Lo LEdd = LIR

Tc = 1000K

R. D. Gehrz (1988, 1990)

R. D. Gehrz


Nova grain properties

Nova Grain Properties ISM, Debris Disks, and Comets

Novae produce carbon, SiC, silicates, and hydrocarbons

Abundances can be derived from visual opacity, IR opacity, and IR emission feature strength

The grains grow to radii of 0.2-0.7m

R. D. Gehrz


Amorphous Carbon Grains and SiC in Novae ISM, Debris Disks, and Comets

Gehrz 1988, ARA&A, 26, 377

Iron seems not to be an option

based on abundance arguments

Gehrz et al. 1984, ApJ, 281, 303

R. D. Gehrz


Grain Condensation in Nova QV Vul 1987 (2) ISM, Debris Disks, and Comets

  • Carbon, Silicates, SiC, and PAH grains formed at different epochs

  • suggesting abundance gradients in the ejecta.

  • A. D. Scott (MNRAS, 313, 775-782 (2000)) has shown that this could

  • be explained by an asymmetric ejection due to a TNR on a rotating WD

R. D. Gehrz


Grain Condensation in V842 Cen (1986) ISM, Debris Disks, and Comets

  • Amorphous Carbon

  • Hydrocarbons

  • Silicates

From R. D. Gehrz, 1990, in Physics of Classical Novae, eds. A. Cassatella and R. Viotti, Springer-Verlag: Berlin, p. 138.

R. D. Gehrz


Carbon and SiC Grains in Nova 1370 Aql (1982) ISM, Debris Disks, and Comets

Data from Gehrz et al. 1984, ApJ, 281, 303

R. D. Gehrz


Grain Condensation in V705 Cas (1993) ISM, Debris Disks, and Comets

  • s

Free-free, amorphous carbon, silicates, and hydrocarbon UIR emission are required to fit the IR spectrum in detail.

There are many variables – constraining data are needed

R. D. Gehrz


Modeling the IR SED of V705 Cas (1993) ISM, Debris Disks, and Comets

There are many variables – constraining data are needed

See C. Mason et al. 1998, ApJ, 494, 783

R. D. Gehrz


Silicates in the diffuse ism toward the gc

Silicates in the Diffuse ISM Toward the GC ISM, Debris Disks, and Comets

J. E. Chiar et al., ApJ, 537, 749 (2000)

R. D. Gehrz


Silicates in regions of star formation

Silicates in Regions of Star Formation ISM, Debris Disks, and Comets

R. D. Gehrz


Hydrocarbons in regions of star formation gmcs

Hydrocarbons in Regions of Star Formation (GMCs) ISM, Debris Disks, and Comets

6

8

10

12

14

 In m

http://web99.arc.nasa.gov/~astrochm/UIR.html

R. D. Gehrz


Mineral dust and regions of star formation

Mineral Dust and Regions of Star Formation ISM, Debris Disks, and Comets

"8-13 Micron Maps of the Trapezium Region of the Orion Nebula,"

R.D. Gehrz, J.A. Hackwell and J.R. Smith, 1975, Ap.J. (Letters), 202, L33

R. D. Gehrz


SOFIA and Comets: Mineral Grains ISM, Debris Disks, and Comets

What can SOFIA observations of comets tell us about the origin of the Solar System?

ISO Data

  • Comet dust mineralogy: amorphous, crystalline, and organic constituents

  • Comparisons with IDPs and meteorites

  • Comparisons with Stardust

  • Only SOFIA can make these observations near perihelion

Spitzer Data

The vertical lines mark features of crystalline

Mg-rich crystalline olivine (forsterite)

R. D. Gehrz


Comet grain properties

Comet Grain Properties ISM, Debris Disks, and Comets

R. D. Gehrz


Comet dust and nova dust compared

Comet Dust and Nova Dust Compared ISM, Debris Disks, and Comets

agr  0.7m

agr  0.2m

Comet Hale-Bopp

r = 1.21 AU

 TBB = 253K

  • Both Comet dust and nova dust contain silicates and carbon

  • Comets have coma emission dominated by grains the size of those produced in nova outflows

R. D. Gehrz


Sofia and comets protoplanetary disks

SOFIA and Comets: Protoplanetary Disks ISM, Debris Disks, and Comets

What can SOFIA observations of comets tell us about the origins of our Solar System and other solar systems?

ISO Observations — Adapted from Crovisier et al. 1996, Science 275, 1904 and Malfait et al. 1998, A&A 332, 25

Image of Solar System IDP (Interplanetary Dust Particle)

Disk System

50 microns

ISO Data

Solar System Comet

  • The silicate features in HD 100546 and C/1995 O1Hale-Bopp are well-matched, suggesting that the grains in the stellar disk system and the small grains released from the comet nucleus are similar

R. D. Gehrz


On the Nature of the Dust in the Debris Disk around HD 69830 ISM, Debris Disks, and CometsC. M. Lisse, C. A. Beichman, G. Bryden, and M. C. Wyatt The Astrophysical Journal, 658:584–592, 2007 March 20

Using a robust approach

to determine the bulk average mineralogical composition of the dust, we show it to be substantially different

from that found for comets 9P/Tempel 1 and C/ Hale-Bopp 1995 O1 or for the comet-dominated YSO HD 100546.Lacking in carbonaceous and ferrous materials but including small icy grains, the composition of the HD 69830 dust

most closely resembles that of a disrupted P- or D-type asteroid.

R. D. Gehrz


Comet and debris disk grains compared

Comet and Debris Disk Grains Compared ISM, Debris Disks, and Comets

R. D. Gehrz


SOFIA and Extra-Solar Circumstellar Disks ISM, Debris Disks, and Comets

What can SOFIA tell us about circumstellar disks?

850 µm

JCMT beam

  • SOFIA imaging and spectroscopy can resolve disks to trace the evolution of the spatial distribution of the gaseous, solid, and icy gas and grain constituents

  • SOFIA can shed light on the process of planet formation by studying the temporal evolution of debris disks

53 µm

88µm

Debris disk around e Eridanae

SOFIA

beam sizes

R. D. Gehrz


Astrophysical Silicates in Different Environments ISM, Debris Disks, and Comets

  • Silicates condensing in the winds of evolved oxygen-rich stars are

  • mainly amorphous silicates; Mg-rich crystalline silicates (forsterite

  • and enstatite) are abundant by up to 15% in massive outflows.

  • The diffuse ISM is dominated by amorphous silicates with an

  • upper limit to the crystalline/amorphous mass ratio of ~ 1%.

  • Silicates in molecular clouds are very similar to diffuse ISM

  • silicates; their absorption profiles peak at shorter wavelengths

  • and are characterized by absorption due to molecular ices.

  • Debris disks around some young stellar objects contain a high

  • abundance of Mg-rich crystalline silicates.

  • The crystalline/amorphous silicate ratio (CAR) is very large in comets

  • (as high as 4 in 9P/Tempel 1 during DEEP IMPACT) .

R. D. Gehrz


Conclusions about astrophysical grains

Conclusions about Astrophysical Grains ISM, Debris Disks, and Comets

The chemical composition and physical properties of grains in

stellar winds, the ISM, debris disks, and comets have striking

similarities (C, SiC, Silicates, hydrocarbons, a = 0.2 – 0.7 µm)

Debris disks around young stars and comets have a high

crystalline/amorphous silicate ratio (CAR)

We infer that there was high temperature condensation or

processing of grains in the early Solar Nebula

The amorphous component (and possibly some of the crystalline

component) of comet dust and IDPs may contain presolar grains

that were formed in stellar winds and/or grown in GMCs

R. D. Gehrz


Appendix a gas phase abundances in nova ejecta

Appendix A: Gas Phase Abundances in Nova Ejecta ISM, Debris Disks, and Comets

R. D. Gehrz


SOFIA and Classical Nova Explosions ISM, Debris Disks, and Comets

What can SOFIA tell us about gas phase abundances in

Classical Nova Explosions?

  • Gas phase abundances of CNOMgNeAl

  • Contributions to ISM clouds and the primitive Solar System

  • Kinematics of the Ejection

R. D. Gehrz


Abundances from IR Forbidden Emission Lines ISM, Debris Disks, and Comets

Greenhouse et al. 1988, AJ, 95, 172

Gehrz et al. 1985, ApJ, 298, L47

Hayward et al. 1996, ApJ, 469, 854

R. D. Gehrz


Abundance anomalies in neon novae

Abundance Anomalies in “Neon” Novae ISM, Debris Disks, and Comets

ONeMg TNR’s can produce and excavate isotopes ofCNO, Ne, Na, Mg, Al, Si, Ca, Ar, and S, etc. that are expelled in their ejecta

ONeMg TNR’s are predicted to have highly enhanced22Naand 26Al abundances in their outflows. These isotopes are implicated in the production of the22Ne (Ne-E) and 26Mgabundance anomalies in Solar System meteoritic inclusions :

22Ne via: 22Na  22Ne + e + +  (1/2 = 2.7 yr)

26Mg via: 26Al  26Mg + e + +  (1/2 = 7105 yr)

R. D. Gehrz


Classical novae and abundance anomalies

Classical Novae and Abundance Anomalies ISM, Debris Disks, and Comets

  • Novae process  0.3% of the ISM

  • (dM/dt)novae 7x10-3 M yr-1

  • (dM/dt)supernovae 6x10-2 M yr-1

Gehrz, Truran, and Williams 1993 (PPIII, p. 75) and Gehrz, Truran, Williams, and Starrfield 1997 (PASP, 110, 3) have concluded that novae may affect ISM abundances:

Novae may be important on a global Galactic scale if they produce isotopic abundances that are  10 times SN and  100 times Solar; Ejected Masses calculated from IR/Radio methods give a lower limit

R. D. Gehrz


Chemical abundances in classical novae from ir data 1

Chemical Abundances in ISM, Debris Disks, and CometsClassical Novae from IR Data (1)

R. D. Gehrz


Chemical abundances in classical novae from ir data 2

Chemical Abundances in ISM, Debris Disks, and CometsClassical Novae from IR Data (2)

R. D. Gehrz


Chemical abundances in classical novae from ir data 3

Chemical Abundances in ISM, Debris Disks, and CometsClassical Novae from IR Data (3)

R. D. Gehrz


Summary and conclusions

Summary and Conclusions ISM, Debris Disks, and Comets

IR/Radio data yield quantitative estimates for physical parameters characterizing the nova outburst: D , Lo , Mgas , Tdust , adust , Mdust , Vo , Lo , grain composition, and elemental abundances

Nova ejecta produce all known types of astrophysical grains: amorphous carbon, SiC, hydrocarbons, and silicates

Classical Nova ejecta have large overabundances (factors of 10 to 100) of CNO, Ne, Mg, Al, S, Si

R. D. Gehrz


SOFIA and Classical Nova Explosions ISM, Debris Disks, and Comets

What can SOFIA tell us about the mineralogy of dust produced in

Classical Nova Explosions?

  • Stardust formation, mineralogy, and abundances

  • SOFIA’s spectral resolution and wavelength coverage is required to study amorphous, crystalline, and hydrocarbon components

  • Contributions to ISM clouds and the Primitive Solar System

QV Vul

QV Vul

R. D. Gehrz


ad