June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram1 MERCURY ’ S EXOSPHERE OBSERVATION USING EsPadOnS/CFHT Alain Doressoundiram(LESIA -Observatoire de Paris) François Leblanc (IPSL, France) Cédric Foellmi (LAOG, Grenoble)

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram2 Observed components of Mercury's exosphere H 3  10 9 ~ 23 (hot) 230 (cold)Mariner 10 He 3  ~ 6  10 3 Mariner 10 O 3  ~ 4.4  10 4 Mariner 10 Mariner 10 Solar Occultation (Broadfoot et al. 1976) At terminator: neutral density < 10 7 cm -3 Mariner 10 Radio Occultation (Fjelbo et al. 1976) Electronic density around Mercury < 10 3 cm -3 SpeciesSubsolar column density (cm -2 ) Near surface subsolar density (cm -3 ) Remarks Na  ~ 10 4 From Earth K  10 9 ~ 10 2 From Earth Ca 1.1  10 8 ?From Earth Known Species

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram3  ESPaDOnS is a bench-mounted high- resolution echelle spectrograph/spectropolarimeter fiber-fed from a Cassegrain module  No slit, 1.6 arcsec aperture hole  Spectral range: 360 to 1050 nm at R=80,000  spectroscopy 'star only' mode  Low pointing limit (8°) CFHT, Mauna Kea, Hawaii 3.58-m telescope latitude +19° 50' longitude 155° 28' OBSERVATIONS at CFHT/ESPaDOnS

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram4 Observational campaigns at CFHT  June 2006 run  August 2006  Apply for time in 2007

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram5 Mercury observational circumstances Date of observations: June 2006 Angular size (arcsec) Helio. distance (AU) Geo. Distance (AU) Illum (%) mag SUN 1.6" hole

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram6 UT TIMES

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram7 UT TIMES

Raw data and extraction (Na line) Raw 2D echelle spectrum where 40 spectral orders are seen Order containing the Na D2 and D1 line (589.2 and nm) Na emission line Extracted 1D spectrum nm nm

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram9 Main Objectives  Detect simultaneous Na, K and Ca emission lines  Detect new lines in the spectral range of Espadons  Variability over 3 nights period

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram10 Observations

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram11 Spectrum of the top: Sum of 5 individual exposure with a total time of 300 s of observation of Mercury, Sky has been subtracted  Black solid line Asteroid: one single exposure of 600 s of Pallas, Sky has been subtracted  Blue solid line Solar spectrum from atlas  Orange solid line Spectrum at the bottom: Ratio of the spectrum of Mercury and of the spectrum of the Asteroid Doppler has been evaluated by using the sodium line during the third night (06/18/2006) therefore not very precisely estimated for this night  Orange vertical line: position of the solar line as seen on Earth  Green vertical line: position of the solar line corrected for the doppler of Mercury/Sun and Mercury/The Earth  Blue vertical line: position of the exospheric emission corrected for the doppler of Mercury/The Earth Night 16 June 2006

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June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram13

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June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram15 Spectrum of the top: Sum of 5 individual exposure with a total time of 360 s of observation of Mercury (for this night the spectra were saturated in the red, therefore available data are up to 5270 A), Sky has been subtracted  Black solid line Asteroid: one single exposure of 720 s of Vesta, Sky has been subtracted  Blue solid line Solar spectrum from atlas  Orange solid line Spectrum at the bottom: Ratio of the spectrum of Mercury and of the spectrum of the Asteroid Doppler has been evaluated by using the sodium line during the third night (06/18/2006) therefore not very precisely estimated for this night  Orange vertical line: position of the solar line as seen on Earth  Green vertical line: position of the solar line corrected for the doppler of Mercury/Sun and Mercury/The Earth  Blue vertical line: position of the exospheric emission corrected for the doppler of Mercury/The Earth Night 17 June 2006

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June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram17

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram18

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram19 Spectrum of the top: Sum of 7 individual exposure with a total time of 460 s of observation of Mercury (for this night the spectra were not saturated), Sky has been subtracted  Black solid line Asteroid: one single exposure of 1200 s of Vesta, Sky has been subtracted  Blue solid line Solar spectrum from atlas  Orange solid line Spectrum at the bottom: Ratio of the spectrum of Mercury and of the spectrum of the Asteroid Doppler has been evaluated by using the sodium line during the third night (06/18/2006) therefore not very precisely estimated for this night  Orange vertical line: position of the solar line as seen on Earth  Green vertical line: position of the solar line corrected for the doppler of Mercury/Sun and Mercury/The Earth  Blue vertical line: position of the exospheric emission corrected for the doppler of Mercury/The Earth Night 18 June 2006

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June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram24 Conclusions  CFHT/ESPADON: good plateform (efficiency, low limit) but…no slit (pb of diff refraction)  Detection of Na and K. This is the second time that a simultaneous obs. of Na and K is done  Possible simultaneous detection of Ca  Upper limits for other species (Mg, Al)  Identification of new species  May be but some works to be done to increase Signal/Noise (better normalization...)  Need of a better surface analog (a star analog of the Sun)  Need of longer time of exposure along parallactic axis (to get best S/N)

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram25 Other telescopes used for our program

June 2006 data review meeting, Boston, Nov 2006 Alain Doressoundiram26 NTT/EMMI  EMMI is a multi-purpose instrument used in echelle spectroscopy mode  Whole 385 to 855nm at R=75000, ~0.025 A/pix  Slit: 0,8" width 10" long NTT, La Silla, Chile 3.58-m telescope latitude -29º 15’ longitude 70º 44' 3 nights october nights october 2006