Physics
Scientific paper
Dec 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001agufm.p31a0536k&link_type=abstract
American Geophysical Union, Fall Meeting 2001, abstract #P31A-0536
Physics
1630 Impact Phenomena, 3230 Numerical Solutions, 5470 Surface Materials And Properties, 6213 Dust, 6225 Mars
Scientific paper
Performing spectroscopic measurements during impacts onto Mars we obtain the unique possibility of investigations of the structure and physical properties of the Martian surface and atmosphere, their chemical composition. Many values for various physical parameters may be derived from remote measurements of the radiation emitted during impacts. Radiation absorbed by the surface leads to the losses of volatiles. A thin layer of the Martian air adjacent to the surface being heated may drastically change the gasdynamic flow behind the shock wave due to the 'thermal layer effect". Detection of radiation impulses may be used for searches of fresh impact sites.We have calculated spectral opacity tables for some recognized types of cosmic H-, LL-, C1-chondrites and cometary matter bodies. The chemical composition taken into account in those calculations is based on the extended system of 16 chemical elements: Fe-O-Mg-Si-C-H-S-Al-Ca-Na-K-N-Cr-Mn-Ti-Ni. Similar spectral opacity tables of the Martian soil vapor based on chemical rock analyses of McSween et al., (JGR, V.104E, 8679, 1999) were also generated. A 3D multifrequency radiation transfer code was used to obtain integral and spectral characteristics and angular distributions of radiation emitted by the domain disturbed by the cosmic body impact.We have used gasdynamic parameter distributions after the vertical impacts of 1-100 m radii stony projectiles striking the Martian surface at the velocities of 11-20 km/s obtained by Nemtchinov et al. (AGU Fall Meeting 2001,abstract). The emitted radiation is essentially nonisotropic. To understand what part of disturbed region emits we analyze the spectral directionality diagrams depended on the wavelength range. Some features of the directionality aspect of emitted radiation are connected with the shielding action of dust curtain around the hot ascending cloud. The maximum radiation corresponds to visible and infrared ranges at the onset of impact impulses. The diagrams in visible range show that the main part of radiation belongs to the region inside the shock. Internal part of the disturbed region is opaque. The atmospheric gas mainly screens radiation emitted by the Martian soil vapor. The directionality diagrams in infrared range show that the main part of radiation is emitted by the shock compressed layer on the top of ascending cloud and by narrow dense soil vapor layer near the surface. Radiation of the middle part of vapor is screened by heated atmospheric gas in the cloud. The role of radiation is increased with meteoroid size growing.The work was supported by NASA Grant NRA 98-OSS-08 JURISS.
Kosarev I. B.
Losseva T. V.
No associations
LandOfFree
Characteristics of Radiation Emitted by Disturbed Region After Meteoroid Impact Onto Mars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Characteristics of Radiation Emitted by Disturbed Region After Meteoroid Impact Onto Mars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Characteristics of Radiation Emitted by Disturbed Region After Meteoroid Impact Onto Mars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1239044