Grains and Gas in Classical Nova Ejecta Presolar Grains Workshop, St. Louis, MO, January 28, 2012 R....

Grains and Gas in Classical Nova Ejecta

Presolar Grains Workshop, St. Louis, MO, January 28, 2012 R. D. Gehrz1

Grains and Gas in the Ejecta of Classical Novae

R. D. GehrzDepartment of Astronomy, University of Minnesota



Outline• Novae and Galactic chemical evolution

• Outburst Development

• Physical properties of nova grains

• Gas Phase abundances

• Comparisons with ISM and the Solar System Grains

• Summary



A Classical Nova Explosion: Accretion followed by a TNR



The Role of Classical Novae in Galactic Chemical Evolution



Stardust and Stellar Evolution



IR/Radio Development Phases

R. D. Gehrz (1988, 1990)

• 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 (10-4 M)

• Lo LEdd = LIR for optically thick dust

shells Lo = constant for a long time

in m

Fireball Expansion Phase

Free-Free Expansion Phase

Coronal Phase in ONeMg Novae

Dust Cocoon Phase in CO Novae



Physical Parameters Derivable from IR SED’s and Spectra

• TBB in K and time of the outburst to in JD for expanding photospheres and dust shells

• The apparent luminosity; for blackbodies, f = 1.36 ( f )max in W cm-2

• The free-free self-absorption wavelength c in m

• The outflow velocity Vo in Km s-1 from emission lines



Mass of the Ejecta from IR SED’s

• From Thomson scattering, which dominates the shell opacity during the fireball/free-free transition:

• From c during the optically thin free-free phase:

• Mgas 1-3x10-4 M for ONeMg WD’s

• Mgas 1-5x10-5 M for CO WD’s

M g a s V ot 3 3 1 0 1 3 2. ( ) in M

M g a s V ot c

5 1 0 1 4 5 2 1/ in M

These methods are independent of D as long as Vo is known from IR spectra



Dust Condensation in CO Novae

R. D. Gehrz (1988, 1990)

Dust Formation in NQ Vul

Visual Transition

Lo LEdd = LIR

Tc = 1000K

• Tc 1000 K

•

• , where Vo is the outflow velocity

RcLo

Tc

1 6 4

1 2

/

tcRcV o



IR Spectra of Dust Grains: Molecular Structure

• 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



Nova Grain Properties• 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 0.2-0.7m



Amorphous Carbon Grains in the Ejecta of NQ Vul, LW Ser, and V1668 Cyg

Gehrz et al. 1984, ApJ, 281, 303

Gehrz 1988, ARA&A, 26, 377

Iron seems not to be an option based on abundance arguments



Carbon and SiC Grains in Nova 1370 Aql (1982)

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



Grain Condensation in V842 Cen (1986)

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

• Amorphous Carbon

• Hydrocarbons

• Silicates



Grain Condensation in Nova QV Vul 1987 (2)

• 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



Grain Condensation in V705 Cas (1993)

•

•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



Modeling the IR SED of V705 Cas (1993)

There are many variables – constraining data are neededSee C. Mason et al. 1998, ApJ, 494, 783



Grain Mass, Abundance, and Size

• Mdust from the infrared luminosity of the dust shell:

• Abundance of the grain condensables is given by:

• Grain radius from the optical depth of the visual transition and LIR:

in M Mdust gra inVo t T

B B 1 6 1 0 11 2 2 6.

Mdust

M gas/ compared to solar abundance

a gr LoVo t TB B

2 1 02 2 2 2 6 in m (agr 0.2-0.7m)



Hydrocarbon Dust in Two Recent Novae



Comets as the “Rosetta Stone” of the Solar System

• They are the remaining “planetesimals” from the epoch of planet formation in the primitive Solar nebula

• The material released from comet nuclei during perihelion passage is therefore a sample of the content of this

primordial environment

• IR imaging photometry and spectroscopy can be used to deduce the composition and physical properties of the gas, dust, and ices present when the planets were forming



SOFIA and Comets: Mineral GrainsWhat can SOFIA observations of comets tell

us about the origin of the Solar System?

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

• Comparisons with IDPs and meteorites

• Comparisons with Stardust

• Only SOFIA can make these observations near perihelion

The vertical lines mark features of crystallineMg-rich crystalline olivine (forsterite)

ISO Data

Spitzer Data



Comet Grain Properties



Comet Dust and Nova Dust Compared

Comet Hale-Bopp

• 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

agr 0.2magr 0.7m

r = 1.21 AU TBB = 253K



Novae and the Primitive Solar System: Interplanetary Dust Particles (IDPs)

• IDP’s are composed of sub micron grains within a “Cluster of Grapes” fractal structure tens to hundreds of microns across

• IDP sub- grains are similar in structure, size, and composition to nova “stardust”

• IDP’s have Carbon, Silicate, and hydrocarbon components seen in nova grains



On the Nature of the Dust in the Debris Disk around HD 69830

C. 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.



Abundances from IR Forbidden Emission Lines

Hayward et al. 1996, ApJ, 469, 854Gehrz et al. 1985, ApJ, 298, L47

Greenhouse et al. 1988, AJ, 95, 172



SOFIA and Classical Nova Explosions

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



Abundance Anomalies in “Neon” Novae

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

• ONeMg TNR’s are predicted to have highly enhanced 22Na and 26Al abundances in their outflows. These isotopes are implicated

in the production of the 22Ne (Ne-E) and 26Mg abundance anomalies in Solar System meteoritic inclusions :

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

26Mg via: 26Al 26Mg + e + + (1/2 = 7105 yr)



Classical Novae and Abundance AnomaliesGehrz, 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 process 0.3% of the ISM

• (dM/dt)novae 7x10-3 M yr-1

• (dM/dt)supernovae 6x10-2 M yr-1

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



Chemical Abundances in Classical Novae from IR Data (1)

Nova X Y (nX/ nY)nova

(nX/ nY)

Reference

LW Ser Carbon dust H 15 Gehrz et al. 1980a

QU Vul Al Si 70 Greenhouse et al. 1988

V1974 Cyg Ne Si 35 Gehrz et al. 1994

V705 Cas Silicates H 17 Gehrz et al. 1995a

V1974 Cyg N H 50 Hayward et al. 1996

V1974 Cyg O H 25 Hayward et al. 1996

V1974 Cyg Ne H 50 Hayward et al. 1996





(nX/ nY)

Reference

V705 Cas Carbon dust H 45 Mason et al. 1997

V705 Cas Ca H 20 Salama et al. 1997 (ISO)

V705 Cas O H 25 Salama et al. 1997 (ISO)

V705 Cas Carbon dust H 20 Mason et al. 1998

V1425 Aql N He 100 Lyke et al. 2002 (ISO)

CP Cru N H 75 Lyke et al. 2003 (ISO)

CP Cru O H 17 Lyke et al. 2003 (ISO)

CP Cru Ne H 27 Lyke et al. 2003 (ISO)





(nX/ nY)

Reference

QU Vul Ne H 168 Gehrz et al. 2008 (Spitzer)

QU Vul O H 2.3 Gehrz et al. 2008 (Spitzer)


Presolar Grains Workshop, St. Louis, MO, January 28, 2012

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

20Ne (10-3 cm3STP g-1 IDP)-

22N

e (1

0-3 c

m3 S

TP

g-1

IDP

)-

Anomalous IDPs

Normal IDPs

Normal GSC IDPs

Anomalous GSC IDPs

Normal TTC IDPs

Anomalous TTC IDPs20Ne/22Ne (Solar Wind) = 13.9

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

20Ne (10-3 cm3STP g-1 IDP)-

22N

e (1

0-3 c

m3S

TP

g-1

IDP

)-

Anomalous IDPs

Normal IDPs

Normal GSC IDPs

Anomalous GSC IDPs

Normal TTC IDPs

Anomalous TTC IDPs20Ne/22Ne (Solar Wind) = 13.9

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

Isot

ope

Rat

ios

3He/4He

4He/20Ne

20Ne/22Ne

20Ne/21Ne

<10-8

21Ne/22Ne

Solar Wind

Neon NovaNeon Novae range

SN II range

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

Iso

top

e R

atio

s

3He/4He

4He/20Ne

20Ne/22Ne

20Ne/21Ne

<10-8

21Ne/22Ne

Solar Wind


SN II range


Presolar Grains Workshop, St. Louis, MO, January 28, 2012

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

Isot

ope

Rat

ios

3He nd

3He/4He

4He/20Ne

21Ne/22Ne

20Ne/22Ne

20Ne/21Ne

<10-8

Anomalous IDPs

Normal IDPs


Solar Wind

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

Iso

top

e R

atio

s

3He nd

3He/4He

4He/20Ne

21Ne/22Ne

20Ne/22Ne

20Ne/21Ne

<10-8

Anomalous IDPs

Normal IDPs


Solar Wind



Summary and Conclusions

• 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



Summary and Conclusions: Pre-Solar Clouds

• IR/Radio data show that the mineral composition and size distribution of the “stardust” made by novae are similar to those of the small grains released by comets in the Solar System

• IR/Radio data confirms theoretical predictions suggesting that nova TNRs can produce ejecta that lead to 22Ne (Ne-E) and 26Mg enhancements such as are seen in meteorites

• Novae are therefore a potential source for at least some of Novae are therefore a potential source for at least some of the solids that were present in the primitive Solar Nebulathe solids that were present in the primitive Solar Nebula



Future Research

• Physical parameters and abundances must be obtained for a larger sample of novae to improve statistics

• Observations of stellar populations in M33 will be conducted using SIRTF to understand the global galactic

contributions of classical novae

• Further examination of IDPs and meteoritic inclusions should be made to identify pre-solar grains from novae

Grains and Gas in Classical Nova Ejecta Presolar Grains Workshop, St. Louis, MO, January 28, 2012 R....

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