Download AAS_WFXT_Solar_System_11Jan2010

Solar System Observing Opportunities
D. Christian (CSUN), C. Lisse, A. Ptak, S. Murray (JHU), S. Wolk (CXC)
WFXT Mission Synopsis
One high resolution, high collecting area and wide FOV soft X-ray telescope
with low background to image at least ½ the 0.4 – 7.0 keV sky down to very
low fluxes while characterizing the spectra of millions of x-ray sources.
Key Scientific Parameters
Constant PSF (5” goal HEW) across 1o x 1o FOV
Effective Area ~ 15 x Chandra @ 1 keV (goal 10,000 cm2)
Bandpass ~ 0.4 – 7 keV; Analog to SSDS in X-ray band
Dedicated 2 year survey mission (no GO program)
Calibrated data products released with no proprietary period
Detailed PtSrc and Extended Object Catalogues
Science Goals
Discovery and Characterization of Groups & Clusters
Evolution of AGN Population
Star Forming Galaxies
Halo Stars
Super Nova Remnants
Compact Galactic Objects
Solar System Objects & Nearby Stellar Neighborhood
Abstract
The proposed WXFT mission will be performing 3 deep
wide field surveys of 20000 sq. deg., 3000 sq. deg. and 100
sq. deg. that will include repeated observations and
detections of foreground solar system objects throughout
the course of the mission. WFXT will thus be a bonanza for
solar system x-ray astrophysics. Understanding local soft xray emission processes, driven by scattering of solar x-rays
and charge exchange with the solar wind, means
understanding the nearest, best example of a stellar wind
throughout interplanetary space; understanding the coupled
neutral outflows from Io and their coupling to the rapidly
rotating Jovian dynamo; understanding the influx and
outflow of ISM H and He through the heliosphere; and
understanding emission from the local hot bubble in the
nearby ISM, surrounding the heliosphere.
RASS Solar
System,
Chandra ACIS
Pointed Obs
WFXT’s sensitivity and angular scale allows for vastly improved solar system studies.
WFXT Survey Serendipitous Solar System Science
• Detections of Known Emitters – Comets, Rocky Planets, Gas Giants, & the
Heliosphere
• Large Scale Imaging – Allows for direct, complete study of extended
systems overflowing Chandra & XMM FOVs (e.g. comets, Jupiter)
• Long term monitoring - Variation with solar wind, CMEs, flares. No solar
system object has been monitored for more than a few days.
• Large scale diffuse flux capability allows direct comparison to ENA and
LENA observations of the heliopause.
• Pointed Observations?
Known Solar System X-rays Emitters
Bhardwaj, Lisse, et al. 2007 & Encyclopedia of the Solar System II, 2008
New Possibilities with WFXT : Mercury, Uranus/Neptune? High Latitude & Main Belt
Comets? Trojan Asteroids? Active Centaurs? The Heliopause?
Comets
Venus
Mars
Scattering
Aurora
Charge
Exchange
Rings
Disk
Disk
Saturn
Jupiter
Some of the currently known sources of X-rays in the Solar System. The complete list incl‘s
the Sun, Planets, Comets, Moons, the Io Flux Torus, and the Heliosphere itself. [See excellent
review by Bhardwaj, Lisse, et al. 2007 and ESS 2008]
Potential of a WFXT Solar System Survey:
Serendipitous Comet Detections in the RASS
Dennerl et al. 1997
C/Levy, Sept 1990
C/Levy, Jan 1991
C/Levy, Jan 1991
C/Levy
C/T-K, Nov 1990
C/T-K, Jan 1991
45P/HMP, Jul 1990
faintest comet
ever detected
in Xrays
C/Arai, Nov 1990
RASS detected 7 comets in 8 months
down to a limit of 10-13 erg cm-2 sec-1.
Based on the WFXT projected sensitivity
and sky coverage, our cometary XLF,
and the supply of short (~40) and long
(~70) period comets reaching perihelion
every year, we estimate at least 40
comet detections in the WFXT wide
survey alone, tripling the number of
comets seen in the x-ray. More comet
detections will be found from
observations of Main Belt Comets,
Sungrazing comets, & Active Centaurs.
2. O VII emission at 565 eV
E
E
3. O VIII emission at 654 eV
low abundance of highly charged oxygen  cold wind
high abundance of highly charged oxygen  hot wind
 flux ratios of all observed comets:
C+N / O VII
cold, fast
warm, slow
hot, fast,
disturbed
O VIII / O VII
Bodewits et al. 2007
F
F
G
G
C
C
A
A
B
B
D
D
C+N ~ O VII
1. C and N emission below 500 eV
H
H
O VIII / O VII flux increases
Three competing emission features:
C+N ≪ O VII
Chandra spectra of comets suggest different
emission characteristics as the solar wind varies
WFXT Planetary Observation
Capabilities: SWCX Processes
in the Earth’s GeoCorona.
Detection
of
heavy
neutral
atoms in the Earth’s magnetosphere implies interaction of the
extended cold H envelope of the
Earth with the solar wind via
CXE.
N.B. - SWCX more important than Jeans
escape for terrestrial H loss budget!
Evidence:
- Atmosphere Explorer C 1974
- Arecibo Incoherent Scatter Radar of e- and
neutral H abundances (Maher and Tinsley 1977)
- IMAGE/LENA observations of magnetosheath
quiescent solar behavior (Collier et al. 2001)
- IMAGE/HENA - CME response (Brandt 2001)

WFXT Planetary Observation Capabilities: Venus Disk + Exosphere
Yohkoh SXT
0.25 – 4.0 keV
Venus’ emission Is
dominated by a large
x-ray scattering
component due to
Its proximity to the
Sun.
1995
1991
Chandra ACIS-I
0.4 – 0.9 keV
GOES-7, 8, 10, 12
1.6 – 12.4 keV
Dennerl et al. 2008
WFXT Planetary Observation Capability:
X-ray images of Mars in individual emission lines
Dennerl et al. 2009
Emission centered
Emission in crescent
Emission above and below
on disk.
offset towards the
Sun.
Poles (!?) or in limb-effect
crescent.
Major science question : what, if any, is the effect of Martian weather
(winter/summer, dust storms, etc.) on the x-ray emission?
WFXT Planetary Observation Capability: Jovian X-rays =
Disk Scattering of Solar X-rays + Auroral Precipitation + Polar SWCX
Io, Europa, Ganymede, and the Io
Plasma Torus have been marginally
detected
in
the
X-ray.
Does the IPT provide the S, O atoms
for Jupiter’s Polar X-ray emission?
Need simultaneous map of whole
system!
Have we detected the root of Europa’s
Neutral Atom Torus (Mauk et al.
2003)?
WFXT Planetary Capability: Saturn’s
Rings Shine in Oxygen K Fluorescence
WFXT Planetary Capability: Saturn’s X-ray Lightcurve
Follows the Sun’s Closely; No Auroral Emission Yet
Detected
ROSAT
LTEs
Cravens et al. 2002
WFXT can map instreaming neutral HI, HeI
ISM emitting SWCXE xrays in the Heliosphere
SOHO/SWAN
Ly-Alpha
Koutroumpa et al.
2008
WFXT all-sky, long
term monitoring
capability critical
to finding the
SWCXE spectral
signature in
heliospheric
“background”.
ACIS-S Lunar nightside emission, Wargelin
et al. 2004 (see also
Wargelin et al. 2009
Chandra posters @
this meeting)
XMM RGS, Snowden
et al. 2004
DXS Background
WFXT Survey Serendipitous Solar System Science
Summary & Conclusions
• There is a rich collection of known solar system x-ray objects Comets, Rocky Planets, Gas Giants, & the Heliosphere for WFXT to
study. Most objects have been detected with only a few photons.
• There is an important list of solar system objects that have yet to be
detected in the x-ray : Mercury, the ice giants Uranus/Neptune, the
Main Belt comets,KBOs, and the heliopause.
• Large Scale WFXT Imaging will allow for direct, complete study of
extended systems overflowing Chandra & XMM FOVs (e.g. bright
comets, Jupiter + Moons + magnetosphere)
• Long term WFXT monitoring will allow for direct study of x-ray
emission variation with solar wind, CMEs, flares, planetary rotation
& weather. No solar system object has been monitored for more
than a few days.
• Large scale diffuse flux capability allows direct comparison to ENA
and LENA observations of the heliopause.