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Earth-and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period

We quantitatively investigated the hydrogen addition reactions of acetylene (C2H2) and ethylene (C2H4) on amorphous solid water (ASW) at 10 and 20 K relevant to the formation of ethane (C2H6) on interstellar icy grains. We found that the ASW surface enhances the reaction rates for C2H2 and C2H4 by approximately a factor of 2 compared to those on the pure-solid C2H2 and C2H4 at 10 K, probably due to an increase in the sticking coefficient and adsorption energy of the H atoms on ASW. In contrast to the previous proposal that the hydrogenation rate of C2H4 is orders of magnitude larger than that of C2H2, the present results show that the difference in hydrogenation rates of C2H2 and C2H4 is only within a factor of 3 on both the surfaces of pure solids and ASW. In addition, we found the small kinetic isotope effect for hydrogenation/deuteration of C2H2 and C2H4 at 10 K, despite the requirement of quantum tunneling. At 20 K, the reaction rate of deuteration becomes even larger than that of hydrogenation. These unusual isotope effects might originate from a slightly larger number density of D atoms than H atoms on ASW at 20 K. The hydrogenation of C2H2 is four times faster than CO hydrogenation and can produce C2H6 efficiently through C2H4 even in the environment of a dark molecular cloud.

We present a comprehensive survey of diffuse interstellar bands (DIBs) in 0.91 − 1.32µm with the newly developed near-infrared (NIR) spectrograph WINERED, mounted on the Araki 1.3 m Telescope in Japan. We obtained high-resolution (R = 28, 300) spectra of 25 early-type stars with color excesses of 0.07 < E(B − V ) < 3.4. In addition to the five DIBs previously detected in this wavelength range, we identified 15 new DIBs, 7 of which were reported as DIB "candidates" by Cox. We analyze the correlations among NIR DIBs, strong optical DIBs, and the reddening of the stars. Consequently, we found that all NIR DIBs show weaker correlations with the reddening rather than the optical DIBs, suggesting that the equivalent widths of NIR DIBs depend on some physical conditions of the interstellar clouds, such as UV flux. Three NIR DIBs, λλ10780, 10792, and 11797, are found to be classifiable as a "family," in which the DIBs are well correlated with each other, suggesting that the carriers of these DIBs are connected with some chemical reactions and/or have similar physical properties such as ionization potential. We also found that three strongest NIR DIBs λλ10780, 11797, and 13175 are well correlated with the optical DIB λ5780.5, whose carrier is proposed to be a cation molecule with high ionization potential, indicating that the carriers of the NIR DIBs could be cation molecules.

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