Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/general/PDF/RI/Luisa_Lara.pdf Дата изменения: Mon May 14 16:20:46 2012 Дата индексирования: Wed Feb 6 09:34:04 2013 Кодировка: Поисковые слова: mercury surface

Planetology from the cm to the nm wavelength ranges: Arecibo Observatory, ALMA and IAA-CSIC
R. Rodrigo1/L.M. Lara (IAA-CSIC) Granada (Spain)
1 Visiting Professor at Arecibo Observatory and at

Universidad Metropolitana de Puerto Rico
Luisa M. Lara


Minor bodies and minor planets with ALMA
§ Continuum
­ Asteroids · Map of the shape, large-scale surface features, and surface temperature distributions of the 700 largest objects in the main asteroid belt and the hundred largest Jupiter Trojans. ­ TNOs · Size and albedo measurements of objects in the Kuiper Belt. · Resolving TNO binary systems. · Studying the thermal emission of the largest TNOs.

§ Spectral lines
­ ­ Detecting tenuous atmospheres as the one on Pluto and Triton. Focus on the CO as it controls the termal budget and structure.
Luisa M. Lara


Comets with ALMA
§ Coma
­ ­ ­ ­ ­ ­ Study the chemical diversity of comets. Observe comets from all dynamical classes. Detect minor species and isotopes (14N/15N, D/H). Study the coma kinematics (jets). Good instantaneous uv-coverage. Good spatial resolution.

§ Nucleus
­ Measure sizes, shapes and physical properties as for asteroids and TNOs.

Luisa M. Lara


Minor bodies with Arecibo Observatory
§ Radar echo to
­ ­ ­ ­ Characterize the surface in terms of composition. Characterize the body's roughness at cm and at dm scales. Provide hints of topographic features (as ridges) in the meter scale. Measure the shape, size albedo, spin period, and orbital period for binary systems. ­ Estimate the mass and density of the primary in binary system.

Excellent synergy with ALMA and IR, near-IR and optical data of these bodies
Luisa M. Lara


Arecibo and Goldstone Radar Observations of (175706) 1996 FG3: Preliminary Results"
Lance A. M. Benner et al."


Summary of Radar Observations
Close Approach: 0.101 AU on Nov. 23"

Arecibo"
Nov. 6, 17, 18, 20, 21, and 22" Dec. 14 and 17" 75 m-resolution images and CW echo spectra"

" Goldstone"
Nov. 20, 21, 22, and 25" 150 m-resolution images and CW echo spectra"

" "


Evidence for an equatorial ridge "
1999 KW4" "


Disk-Integrated Results "
Diameter (primary) = 1.9 km" Secondary ~ 0.5 km" Absolute magnitude H = 18.0" Optical albedo = 0.03" " Radar cross section = 1 km2 +- 25%" Radar albedo = 0.35 +-25%" " SC/OC = 0.34 +- 0.02" "


Mass and Density: Preliminary Results "
Maximum separation "= 2.55 km (2011 Nov. 22)" Subradar latitude " "= 16 deg" -> Mass " " "= 3.3E12 kg" -> Density " " "= 0.9 g/cm3" " PLEASE NOTE:" 1. Ignores mass of secondary" 2. Assumes primary is a sphere with D = 1.9 km" 3. Assumes orbit is circular" 4. Uncertainties could easily be >30%" " " " "


Selected Physical Properties
"

Absolute mag.
" " "

"H = 18.005 " "H = 17.76+-0.03 "C

"JPL/Horizons"
"Pravec et al. 2006"

Spectral class: Albedo
Diameter

"

"

"Bu

s and Binzel 2002"

"
"

"pv = 0.029

+0.026-0.012Mueller et al. 2011"

"1.9 +0.55-0.42 km

"Mueller et al. 2011"

"
Binary system: (Pravec et al. 2006)" Primary

" "

" "

" " "

"P = 3.5942 +-0.0 "m = 0.08 mag
"P = 16.14 h "

001 h"

"low elongation" "synchronous" "moderately elongated"

Secondary "

"m = 0.4 mag


Atmospheres with ALMA (mm & sub-mm)
§ Spectrally resolved measurements of molecular lines
Thermal sounding, i.e. determination of p-T-z profiles. Chemical sounding, i.e. molecular abundances and their vertical profile. Dynamical sounding, i.e. wind velocities from Doppler shift measurements.

§ These three parameters are intimately coupled
Temperature field Ю wind field. Wind field Ю horizontal/vertical distribution of minor species. Minor species Ю temperature field through atmospheric heat budget (heating and cooling).

Dynamical view of planetary atmospheres
Luisa M. Lara


What ALMA provides
§ High spectral resolution:
­ line shapes, atmospheric temperature structure, vertical profiles of molecular abundances

§ Instanteneous uv-coverage:
­ time variable phenomena

§ Sensitivity:
­ weaker lines, more distant objects, more tenuous atmospheres

§ Broad bandwidth:
­ search for broader lines in deep atmospheres of Venus and giant planets

Luisa M. Lara


Atmosphereless planets and satellites
§ Mercury § Jupiter's and Saturn's Satellites:
­ If T~100 K and mainly water ice on the surface, absorption at radio wl is negligible Х sounding subsurface of these bodies (multiple scattering as preserves the polarization sense under circularly polarized illumination)+ probing surface structures at cm and dm scales. ­ Investigate the leading and trailing hemispheres (with well known dichotomies in several cases). ­ Constrain the "degree of contamination" of the superficial water ice by non ice-contaminants. ­ Comparison with other radar measurements (ex. Enceladus at 2.2 cm with the CASSINI radar and Arecibo Observatory at 13 cm is different) Х ­ Synergy with future mission/s to Jupiter system (JUNO-NASA and JUICE-ESA) to explore the planet and the Galilean Satellites.
Luisa M. Lara