Talk presented by Jan-Uwe Ness (XMM-Newton Science Operations Centre) at the symposium "From atoms to stars: the impact of spectroscopy on astrophysics", Oxford, UK, 28-28 July 2011.
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
Application of X-ray plasma diagnostics to nova winds
1. XMM-Newton Chandra
Application of X-ray Plasma
Diagnostics to Nova Winds
Jan-Uwe Ness
XMM-Newton Science Operations Centre Swift
European Space Astronomy Centre
(ESAC)
2. The RS Oph system
Recurrent Nova with
6 recorded outbursts
since 1898
5. outburst
Accreted
material:
H-rich!
Nuclear
burning
ignites WD
enough radiative
energy is produced
to drive a wind with
v ≈ 1500 km s-1
6. Radiatively driven expansion
Pseudo
Stellar
Nuclear Atmosphere
burning
equivalent to
a stellar
radiation zone
6 m WD
0 x10 k
R=10 ay
aft er 1 d
Photosphere
brightest in optical -> discovery
7. Pseudo
Stellar
Nuclear Atmosphere
burning
WD
Photosphere
Density drops, outer layers go optically thin
=> Radius of Photosphere recedes to inner, hotter, layers
8. Pseudo
Stellar
Nuclear Atmosphere
burning
WD
Photosphere
=> fades in optical but Lbol constant
=> spectrum shifts to higher energies ...
9. Pseudo
Stellar
Nuclear Atmosphere
burning
Super-Soft-Source
X-ray spectrum
WD
⇒ SSS phase
Photosphere
.... until the peak of the spectrum reaches soft X-rays
--> direct observations of nuclear burning
13. Novae are powered by nuclear burning
The pressure is not high enough on a WD
surface to produce any elements heavier
than Helium
The CNO cycle changes the relative
abundances of C, N, and O
If the nova ejecta show any other
anomalies in composition, then either
- WD material has been dredged up
- The companion is anomalous
14. Shock with
stellar wind
SSS Emission
from hot white
dwarf + giant in
Symbiotic Novae
+ MS star in
Classical Novae
15. Swift observations of RS Oph Osborne et al. (2011)
shock phase SSS phase nebular phase
optical
16. Swift observations of RS Oph Osborne et al. (2008)
shock phase SSS phase nebular phase
XMM-Newton------------
Chandra
Chandra
Chandra/XMM
XMM-Newton
Chandra
31. RS Oph secondary has
[N/Fe]=0.9:
(Pavlenko et al. 2008)
=> 20-40% of N from
outburst or companion
32. Sample of M giants by
Smith & Lambert (1985/86)
RS Oph secondary has
[N/Fe]=0.9:
(Pavlenko et al. 2008)
=> 20-40% of N from
outburst or companion
33. Sample of M giants by Rich et al. (2007)
Mg, Si not produced in outburst
=> must come from WD or companion
34. Summary
The companion in Symbiotic Novae is a
giant star that has similar abundance ano-
malies as those expected in nova ejecta
The abundances for RS Oph appear more
anomalous than for typical stars of the
same spectral type as the companion
We might be seeing WD material
=> too many heavy elements for SN Ia
But: The companion in symbiotics is
stripped off the outer layers, exposing
layers with different abundances.