Supplementary Figure Legends:
Supplementary Figure 1: Description of the experimental device (see the schematic drawing of the experimental
device).
The apparatus consists of a reaction chamber linked to a high-vacuum metal line in which mixture of gases can flow
(CO2, Ar, He, CO…). Vacuum (10-9 bar to 1 bar) is achieved by a primary pump and a turbo-molecular pump. In this
study, experiments were performed in static vacuum mode at different total pressures. Pressure is controlled by a
baratron gauge during the course of all experiments. The production of a multi-elemental refractory gas with a
constant composition over time is achieved using a pulsed Nd-Yag laser (1064 nm) which ablates a spinning glass
target located at the bottom of the reaction chamber. The laser (~10 mJ-10ns) is focused on a ~0.2 mm2 area yielding
about ~1 mg/h of ablated material. In addition to allow an accurate control of the gas composition, the use of a glass
target ensures the absence of ejected crystals from the target in the collected material. For most of the experiments,
the condensation temperature was ~ 25°C (room temperature) and condensates were collected on a horizontal plate
approximately 2 to 10 cm above the target (collection yield of ~8-10% on a 1.5 cm diameter horizontal steel plate
located 3 cm above the target). To perform condensation experiments at higher temperature, a cylindric platinum
furnace was sited above the condensation zone (see figure), resulting in a negative temperature gradient below the
furnace. Temperature of condensation (± 35°C) was then controlled using a thermocouple either welded to vertical
platinum-grids or in close contact with the horizontal steel plates. A typical experiment at 25°C takes place in several
steps: (1) installation of the collection plate and the glass target in the reaction chamber, (2) heating (200°C) and
pumping of the reaction chamber in order to reach a vacuum of ~ 10 -6 bar, (3) flowing of CO2 or Argon in the metal
line at the desired partial pressure, (4) opening of the reaction chamber to the water container which temperature is
controlled to reach the desired water partial pressure, (4) laser ablation of the glass target. Condensation time is
defined as the time of ablation. When experiments were performed at temperature > 25°C, the Pt-furnace was heated
until thermal equilibrium before operating the laser. The experiment was ended by shutting off the power of the
furnace followed by that of the laser.
The ablated glasses were synthesised from mixtures of reagent grade oxides (SiO2, Al2O3, MgO) and carbonates
(CaCO3), twice fused in air at 1600°C and 1400°C for the "solar" and Ca-Al-rich composition respectively.
Parallelepipeds of glass were then sliced and depolished to improve laser absorption at 1064 nm. Compositions were
checked by electron microprobe analyses using a Cameca SX50 at "Service Commun de Microanalyses" of the Henri
Poincaré University, Nancy, France.
Supplementary Figure 2: Far-infrared spectrum (700-50 cm-1) of Ca-Al-rich material condensed in "wet" CO2 (25°C,
20 mbar H2O + 4 mbar CO2, 493 min). Bands at 642, 589 and 437 cm-1 can be assigned to O-Si-O bending vibrations
(Koike and Tsuchiyama, 1992) and bands at 318, 227 and 110 cm-1 can be assigned to carbonate, similar to calcite
lattice vibrations (Kemper et al., 2002). Bands at 176 and 140 cm-1 could be either related to hydrated carbonate or to
highly bonded water vibrations. Bands at 561 cm-1 correspond to an experimental artefact.
Supplementary Figure 3: Mid-infrared transmission spectra (4000-600 cm-1) of material condensed at 25°C in ~20
mbar H2O and ~4 mbar CO2 from Ca-Al-rich (50 min - 289) and "solar" gas (50 min - 284). Note the similarity
between the two spectra, suggesting a similar chemical composition for the carbonate for both composition. The
amount of carbonate formed from a "solar" gas (Ca/Si ratio of 0.25) is slightly less important than that from a Ca-Alrich gas (Ca/Si ratio of 0.44). Note that the intensity of the shoulder at 1115 cm-1 decreases with the amount of
carbonate, confirming the association of this band with the carbonate forbidden symmetric stretching 1 (indicated by
a star on the figure).
Supplementary Figure 4: Mid-infrared transmission spectra (4000-600 cm-1) of material condensed at 25°C in "wet"
CO2 for two different times (55 min, sample 130; 464 min, sample 204). The condensation time has no large effect
on the amount of total water, carbonate content or structure of the carbonate. Because the CO 2 partial pressure
decreases during the course of the experiment, an increase of the condensation time has however a slight effect on
the intensity of the 1590 cm-1 peak, with a decrease of the highly-bonded water and on the ratios of the different
fitted peaks of the carbonate 3 (e.g. 1360/1430, see Table 1).
Supplementary Figure 5: Mid-infrared transmission spectra (4000-600 cm-1) of material condensed in "wet" CO2
under different temperatures (25°C, sample 204; 50°C, sample 124; 130°C, sample 126). An increase of the
temperature is mainly associated to a decrease of total water and carbonate content and to a cristallo-chemical change
of the carbonates with a decrease of the 1360 and 1320 cm-1 bands and the apparition of a new band around 1520 cm1
. Because condensation time only affects the intensity ratio of the fitted peaks and not their position, such cristallo-
chemical change is not due to the variation in the condensation time (see Figure 2 of Supplementary Data). The
major silicate peak shifts from 1020 cm-1 to 1000 cm-1 with increasing temperature of condensation, certainly due to
a change in the degree of polymerization of the silicate tetrahedrons (amount of alkaline-earth elements, less amount
of water) and a change in the carbonate structure leading to a less intense carbonate 1 band.
Supplementary Figure 6: Mid-infrared transmission spectra (4000-600 cm-1) of material condensed at 25°C under
different "wet" CO2 partial pressures. A decrease in the partial pressure of CO 2 (PCO2) yields (1) a slight decrease in
the amount of carbonates and of associated highly bonded water and (2) an increase of the carbonate 1480 cm-1 band
with a decrease of the other bands, relative to the 1430 cm-1 one, revealing thus a structural change of the carbonate.
References:
Kemper, F., Jäger, C., Waters, L.B.F.M., Henning, Th., Molster, F.J., Barlow, M.J., Lim, T., de Koter, A. (2002)
Detection of carbonates in dust shells around evolved stars. Nature 415, 295-297.
Koike, C., Tsuchiyama, A. (1992) Simulation and alteration for amorphous silicates with very broad bands in
infrared spectra. Mon. Not. R. Astro. Soc. 255, 248-254.