The first steps of planet formation are marked by the growth and crystallization of sub-micrometer-sized dust grains accompanied by dust settling toward the disk midplane. In this paper we explore whether the first steps of planet formation are affected by the presence of medium-separation stellar companions. We selected two large samples of disks around single and binary T Tauri stars in Taurus that are thought to have only a modest age spread of a few Myr. The companions of our binary sample are at projected separations between ∼10 and 450 AU with masses down to about 0.1 M ⊙ . We used the strength and shape of the 10 µm silicate emission feature as a proxy for grain growth and for crystallization respectively. The degree of dust settling was evaluated from the ratio of fluxes at two different mid-infrared wavelengths. We find no statistically significant difference between the distribution of 10 µm silicate emission features from single and binary systems. In addition, the distribution of disk flaring is indistinguishable between the single and binary system samples. These results show that the first steps of planet formation are not affected by the presence of a companion at tens of AU.

We present an early broad-brush analysis of Herschel/PACS observations of star-forming galaxies in 8 galaxy clusters drawn from our survey of 30 clusters at z 0.2. We define a complete sample of 192 spectroscopically confirmed cluster members down to L TIR > 3 × 10 10 L and L K > 0.25 L K . The average K-band and bolometric infrared luminosities of these galaxies both fade by a factor of ∼2 from clustercentric radii of ∼2 r 200 to ∼0.5 r 200 , indicating that as galaxies enter the clusters ongoing star-formation stops first in the most massive galaxies, and that the specific star-formation rate (SSFR) is conserved. On smaller scales the average SSFR jumps by ∼25%, suggesting that in cluster cores processes including ram pressure stripping may trigger a final episode of star-formation that presumably exhausts the remaining gas. This picture is consistent with our comparison of the Herschel-detected cluster members with the cluster mass distributions, as measured in our previous weak-lensing study of these clusters. For example, the spatial distribution of the Herschel sources is positively correlated with the structures in the weak-lensing mass maps at ∼5σ significance, with the strongest signal seen at intermediate group-like densities. The strong dependence of the total cluster IR luminosity on cluster mass -L TIR ∝ M 2 virial -is also consistent with accretion of galaxies and groups of galaxies (i.e. the substructure mass function) driving the cluster IR luminosity. The most surprising result is that roughly half of the Herschel-detected cluster members have redder S 100 /S 24 flux ratios than expected, based on the Rieke et al. models. On average cluster members are redder than non-members, and the fraction of red galaxies increases towards the cluster centers, both of which indicate that these colors are not attributable to systematic photometric errors. Our future goals include to intepret physically these red galaxies, and to exploit this unique large sample of clusters with unprecedented multi-wavelength observations to measure the cluster-cluster scatter in S0 progenitor populations, and to intepret that scatter in the context of the hierarchical assembly of clusters.

A B S T R A C TWe observed nine primary transits of the hot Jupiter TrES-3b in several optical and near-UV photometric bands from 2009 June to 2012 April in an attempt to detect its magnetic field. Vidotto, Jardine and Helling suggest that the magnetic field of TrES-3b can be constrained if its near-UV light curve shows an early ingress compared to its optical light curve, while its egress remains unaffected. Predicted magnetic field strengths of Jupiter-like planets should range between 8 G and 30 G. Using these magnetic field values and an assumed B * of 100 G, the Vidotto et al. method predicts a timing difference of 5-11 min. We did not detect an early ingress in our three nights of near-UV observations, despite an average cadence of 68 s and an average photometric precision of 3.7 mmag. However, we determined an upper limit of TrES-3b's magnetic field strength to range between 0.013 and 1.3 G (for a 1-100 G magnetic field strength range for the host star, TrES-3) using a timing difference of 138 s derived from the Nyquist-Shannon sampling theorem. To verify our results of an abnormally small magnetic field strength for TrES-3b and to further constrain the techniques of Vidotto et al., we propose future observations of TrES-3b with other platforms capable of achieving a shorter near-UV cadence. We also present a refinement of the physical parameters of TrES-3b, an updated ephemeris and its first published near-UV light curve. We find that the near-UV planetary radius of R p = 1.386 +0.248 −0.144 R Jup is consistent with the planet's optical radius.

We present wide-field Herschel/PACS observations of A 1689, a massive galaxy cluster at z = 0.1832, from our open time key programme. We detect 39 spectroscopically confirmed 100 μm-selected cluster members down to 1.5 × 10 10 L . These galaxies are forming stars at rates in the range 1-10 M /yr, and appear to comprise two distinct populations: two-thirds are unremarkable blue, late-type spirals found throughout the cluster; the remainder are dusty red sequence galaxies whose star formation is heavily obscured with A(Hα) ∼ 2 mag and are found only in the cluster outskirts. The specific-SFRs of these dusty red galaxies are lower than the blue late-types, suggesting that the former are in the process of being quenched, perhaps via pre-processing, the unobscured star formation being terminated first. We also detect an excess of 100 μm-selected galaxies extending ∼6 Mpc in length along an axis that runs NE-SW through the cluster center at > ∼ 95% confidence. Qualitatively this structure is consistent with previous reports of substructure in X-ray, lensing, and near-infrared maps of this cluster, further supporting the view that this cluster is a dynamically active, merging system.

Broad infrared emission features (e.g., at 3.3, 6.2, 7.7, 8.6, and 11.3 µm) from the gas phase interstellar medium have long been attributed to polycyclic aromatic hydrocarbons (PAHs). A significant portion (10%−20%) of the Milky Way's carbon reservoir is locked in PAH molecules, which makes their characterization integral to our understanding of astrochemistry. In molecular clouds and the dense envelopes and disks of young stellar objects (YSOs), PAHs are expected to be frozen in the icy mantles of dust grains where they should reveal themselves through infrared absorption. To facilitate the search for frozen interstellar PAHs, laboratory experiments were conducted to determine the positions and strengths of the bands of pyrene mixed with H 2 O and D 2 O ices. The D 2 O mixtures are used to measure pyrene bands that are masked by the strong bands of H 2 O, leading to the first laboratory determination of the band strength -2for the CH stretching mode of pyrene in water ice near 3.25 µm. Our infrared band strengths were normalized to experimentally determined ultraviolet band strengths, and we find that they are generally ∼50% larger than those reported by Bouwman et al. based on theoretical strengths. These improved band strengths were used to reexamine YSO spectra published by Boogert et al. to estimate the contribution of frozen PAHs to absorption in the 5−8 µm spectral region, taking into account the strength of the 3.25 µm CH stretching mode. It is found that frozen neutral PAHs contain 5%−9% of the cosmic carbon budget, and account for 2%−9% of the unidentified absorption in the 5−8 µm region.