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It has been noted (Lieu & Hillmann) that the cumulative effect of Planck-scale phenomenology, or the structure of spacetime at extremely small scales, can be lead to the loss of the phase of radiation emitted at large distances from the observer. We elaborate on such an approach and demonstrate that such an effect would lead to an apparent blurring of distant point sources. Evidence of the diffraction pattern from the Hubble Space Telescope observations of SN 1994D and the unresolved appearance of a Hubble Deep Field galaxy at lead us z p 5.34 to put stringent limits on the effects of Planck-scale phenomenology.

An overview of the current status of the 8.2 m Subaru Telescope constructed and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of Japan is presented. The basic design concept and the verified performance of the telescope system are described. Also given are the status of the instrument package offered to the astronomical community, the status of operation, and some of the future plans. The status of the telescope reported in a number of SPIE papers as of the summer of 2002 are incorporated with some updates included as of 2004 February. However, readers are encouraged to check the most updated status of the telescope through the home page, http://subarutelescope.org/index.html, and/or the direct contact with the observatory staff.

We present medium-resolution 3 lm spectroscopy of the carbon-rich proto-planetary nebula IRAS 22272+5435. Spectroscopy with the Subaru Telescope adaptive optics system revealed a spatial variation of hydrocarbon molecules and dust surrounding the star. The rovibrational bands of acetylene (C 2 H 2 ) and hydrogen cyanide (HCN) at 3.0 lm are evident in the central star spectra. The molecules are concentrated in the compact region near the center. The 3.3 and 3.4 lm emission of aromatic and aliphatic hydrocarbons is detected at 600-1300 AU from the central star. The separation of spatial distribution between gas and dust suggests that the small hydrocarbon molecules are indeed the source of solid material and that the gas left over from the grain formation is being observed near the central star. The intensity of aliphatic hydrocarbon emission relative to the aromatic hydrocarbon emission decreases with distance from the central star. The spectral variation is well matched to that of a laboratory analog thermally annealed with different temperatures. We suggest that either the thermal process after the formation of a grain or the variation in the temperature in the dust-forming region over time determines the chemical composition of the hydrocarbon dust around the proto-planetary nebula.

Abstract. We present the results of our monitoring of comet 81P/Wild 2, the target of the S mission. Broad-band filter images and medium resolution spectra of this comet obtained along its pre-and postperihelion orbit between 1996 and 1998 were analysed in terms of coma morphology and activity. The morphological coma investigation revealed the presence of longlasting fan structures, which remained essentially unchanged for at least three months. The (B − V) and (V − R) colour indices were determined at three different positions along the orbit. The two-dimensional analysis showed a uniform colour over the entire coma. Hence, the material composing the structures is not different from that of the underlying coma. The distribution of coma brightness as a function of projected distance from the nucleus shows no peculiarities. The evolution of the comet's activity during the pre-and postperihelion phase appears to be asymmetric in that activity increases faster preperihelion than it decreases postperihelion. The production rates (or their upper limits in the case on a non-detection) of CN, C 2 , C 3 , and NH 2 were determined from the spectrophotometric observations and compared to other values published in the literature.

We report the carbon monoxide isotope ratio in local molecular clouds toward LkH 101, AFGL 490, and Mon R2 IRS 3. The vibrational transition bands of 12 CO ¼ 2 0 and 13 CO ¼ 1 0 were observed with high-resolution near-infrared spectroscopy (R ¼ 23; 000) to measure the 12 CO/ 13 CO ratio. The isotopic ratios are 12 CO/ 13 CO ¼ 137 AE 9 (LkH 101), 86 AE 49 (AFGL 490), and 158 (Mon R2 IRS 3), which are 1.5-2.8 times higher than the local interstellar medium value of 12 CO/ 13 CO ¼ 57 AE 5 from millimeter C 18 O emission observations. This is not easily explained by saturation of the 13 CO absorption. It is also questionable whether the selective photodestruction of 13 CO can account for the difference between the Galactic trend and the present observation, because the molecular clouds are with high visible extinction (A V ¼ 10 70 mag), well shielded from destructive FUV radiation. The molecular gas associated with AFGL 490 and Mon R2 IRS 3 consists of multiple temperature components lying in the lines of sight. In the cool component (T ex < 100 K), the excitation temperature of 12 CO is twice that of 13 CO. We attribute the temperature discrepancy to the photon-trapping effect, which makes the radiative cooling of the main isotopomer less effective.

We present 3 µm spectroscopy of the carbon-rich proto-planetary nebulae IRAS 04296+3429 and IRAS 05341+0852 conducted with the adaptive optics system at the Subaru Telescope. We utilize the nearly diffraction-limited spectroscopy to probe the spatial extent of the hydrocarbon dust emitting zone. We find a hydrocarbon emission core extending up to 100-160 mas from the center of IRAS 04296+3429, corresponding to a physical diameter of 400-640 AU, assuming a distance of 4 kpc. On the other hand, we find that IRAS 05341+0852 is not spatially resolved with this instrumentation. The physical extent of these proto-planetary nebulae, along with the reanalyzed data of IRAS 22272+5435 published previously, suggests a correlation between the physical extent of the hydrocarbon dust emission and the spectral evolution of the aliphatic to aromatic features in these post-AGB stars. These measurements represent the first direct test of the proposed chemical synthesis route of carbonaceous dust in the circumstellar environment of evolved stars.

We present near-infrared spectroscopy of low-mass companions in a nearby triple system HD 130948 (Gliese 564, HR 5534). Adaptive optics on the Subaru Telescope allowed spectroscopy of the individual components of the 0. ′′ 13 binary system. Based on a direct comparison with a series of template spectra, we determined the spectral types of HD 130948B and C to be L4 ± 1. If we take the young age of the primary star into account (0.3-0.8 Gyr), HD 130948B and C most likely are a binary brown dwarf system.