X-rays from Mars K. Dennerl, C. Lisse, A. Bhardwaj, V. Burwitz, J. Englhauser, H. Gunell, M. Holstrom, F. Jansen, V. Kharchenko, and P. Rodriguez-Pascual Chandra XMM Halo (CXE) Disk (scattering)

There Are Many Sources of X-rays in the Solar System (Planets, Moons, Io Flux Torus, Comets, Sun); But the keV Emission Mechanisms Are Still Uncertain. Venus Mars Saturn JupiterComets Auroral Scattering Charge Exchange Excellent new review of the current understanding of s.s. xrays : Bhardwaj et al., PSS 55, 1135 (2007)

January 2001: first X-ray image of Venus (Chandra ACIS-I) First X-ray observation of Venus during solar maximum: Scattering of solar X-rays detected, but no conclusive evidence of charge exchange. => To understand the charge exchange component, the solar wind flux and charge state will have to be very well known. The first two-spacecraft measure of the solar wind at another planet, by MESSENGER and Venus Express during the V2 flyby, will provide this data. Dennerl et al. 2002, A&A 386, 319 Solar X-rays Venus ACIS-I

Planning the Mars observation 2001 July 4

Catching Mars with Chandra

Optical depth of the Martian atmosphere

Simulated X-ray images of Mars due to fluorescent scattering of solar X-rays C-K α L x ~ 2.9 MW N-K α L x ~ 0.1 MW O-K α L x ~ 1.7 MW

Chandra observation Spatial distribution of X-ray photons around Mars

Spectral distribution of X-ray photons around Mars background Chandra observation

Gunell et al. 2004, Geophysical Research Letters 31 Trajectories for O 6+ ions around Mars 90°60° 30°0° Parallel projection of X-ray emission on 4 July 2001 X-ray imaging of the solar wind – Mars interaction Holmström, Barabash, Kallio, Geophysical Research Letters 28, , 2001 Parallel projections of X-ray emission at solar minimum 18.2°

Chandra observation Charge exchange simulation Gunell et al. 2004, Geoph. Res. Letters 31 Spatial distribution of X-ray photons around Mars

Mars observed with XMM-Newton 2003 Nov 20, 00:08 – Nov 21, 04:57 UTC XMM-Newton

Mars observed with XMM-Newton 2003 Nov 20, 00:08 – Nov 21, 04:57 UTC

XMM-Newton observation of Mars EPIC pn sky coordinates X-ray image exposure map

pixel size: 1“ pixel size: 5“ XMM-Newton images of Mars

Solar X-ray flux ( keV)

+ 10“ - 10“ “disk” High resolution X-ray spectroscopy of Mars with RGS dispersion direction G(O +6 ) = (f+i)/r = 0.8 +/- 0.6, i=0 L x = 3.4 +/- 0.4 MW C 5+ N 6+ O 6+ CO 2 O 7+ Ne 7+ ? C 4+ N2

“halo” + 15“ + 50“ - 15“ - 50“ High resolution X-ray spectroscopy of Mars with RGS C 5+ N 6+ O 6+ CO 2 O 7+ Ne 7+ ? C 4+ G(O +6 ) = (f+i)/r = 5 - 6, i =0 L x = /- 1.4 MW O +8/ O +7 = /- 0.10

High resolution X-ray spectroscopy of Mars with RGS halo disk C 5+ N 6+ O 6+ CO 2 O 7+ Ne 7+ ? C 4+

High resolution X-ray spectroscopy of Mars

X-ray line emission from Mars solar wind ions charge exchange 12.8 ± 1.4 MW Mars atmosphere fluorescence 3.4 ± 0.4 MW

High resolution X-ray spectroscopy of Mars with RGS

High resolution X-ray spectroscopy of Mars

X-ray images of Mars in individual emission lines (!) O 7+ : 2p → 1s O 6+ : 2 3 S 1 → 1 1 S 0

X-ray images of Mars in individual emission lines (!)

C 5+ : 3p → 1s C 5+ : 2p → 1s

X-ray images of Mars in individual emission lines (!)

N 2 : 2p → 1s CO 2 : 4 σ g → 1s, 3 σ u → 1s, 1 π u → 1s CO 2 : 1 π g → 1s

X-ray images of Mars in individual emission lines (!)

Emission centered on disk. Emission in crescent offset towards the Sun. Emission above and below Poles (!?) or in limb-effect crescent.

X-ray color image of Mars

Fin.

Questions : Is Ne72 line really Ne82 line? Ne +7 is lithium like, should have a low energy transition, not one at eV. The Ne +8 lines are at 905, 916, and 922 eV. (Ali) How is RGS data binned? Non-linear, so is 872 eV really 872, or maybe eV or 830? (Wargelin) What is the composition of the Martian exosphere in the Holstrom et al. model? All H? No C, O, CO 2 ? Viking may be the only s/c to measure exosphere composition. Was Mars in Northern summer in 2003, explaing brighter emission of O on the North? (Cravens, Kharchenko) What does the spatial extent of the CO 2 tell you? Is the apparent CO 2 in the halo due to the coarse XMM imaging (PSF wings), or due to CO 2 in the exosphere? Is the halo emission overlapped by emission from the extended Martian disk? (Kharchenko) How good are the SNR of the different lines in the disk and halo fits? 2 pts not fit at 385 eV seem as significant as fit lines at other wavelengths (Beiersdorfer) What is the spectral profile of the O +6 f,I,r lines? (Kharchenko) O +8 /O +7 ratios varies a LOT in the SW. SW O +8 /O +7 ratio varies by up to 2 orders of magnitude. We have to be careful when comparing to an “average”. Also, how can the O +7 /O +6 ratio be 0.34, yet the solar wind flux and activity be 10x higher than during the CXO observations in 2001? I.e., cold stable wind ratios with very high density? (Edgar)