We present high-resolution, H-band imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm ...imagery suggested the existence of a dust-depleted cavity at r < or =, slant 46 AU, our observations reveal the presence of scattered light components as close as 0".2 (~28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0".5 (~70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h ~ 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelength observations.
We conduct a statistical analysis of a combined sample of direct imaging data, totalling nearly 250 stars. The stars cover a wide range of ages and spectral types, and include five detections ( Kappa ...And b, two ~60 M sub(J) brown dwarf companions in the Pleiades, PZ Tel B, and CD-35 2722B). For some analyses we add a currently unpublished set of SEEDS observations, including the detections GJ 504b and GJ 758B. We conduct a uniform, Bayesian analysis of all stellar ages using both membership in a kinematic moving group and activity/rotation age indicators. We then present a new statistical method for computing the likelihood of a substellar distribution function. By performing most of the integrals analytically, we achieve an enormous speedup over brute-force Monte Carlo. We use this method to place upper limits on the maximum semimajor axis of the distribution function derived from radial-velocity planets, finding model-dependent values of ~30-100 AU. Finally, we model the entire substellar sample, from massive brown dwarfs to a theoretically motivated cutoff at ~5M sub(J), with a single power-law distribution. We find that p(M, a) is proportional to M super(-0.65+ or -0.60 )a -0.85+ or -0.39 (1sigma errors) provides an adequate fit to our data, with 1.0%-3.1% (68% confidence) of stars hosting 5-70M sub(J) companions between 10 and 100 AU. This suggests that many of the directly imaged exoplanets known, including most (if not all) of the low-mass companions in our sample, formed by fragmentation in a cloud or disk, and represent the low-mass tail of the brown dwarfs.
A recent study of soft x-ray absorption in native and hydrogenated coronene cations, C_24H_12+m^+ m=0–7, led to the conclusion that additional hydrogen atoms protect (interstellar) polycyclic ...aromatic hydrocarbon (PAH) molecules from fragmentation Reitsma et al., Phys. Rev. Lett. 113, 053002 (2014). The present experiment with collisions between fast (30–200 eV) He atoms and pyrene (C_16H_10+m^+, m=0, 6, and 16) and simulations without reference to the excitation method suggests the opposite. We find that the absolute carbon-backbone fragmentation cross section does not decrease but increases with the degree of hydrogenation for pyrene molecules.
With the uniquely high contrast within 0".1 ( Delta mag(L') = 5-6.5 mag) available using Sparse Aperture Masking with NACO at Very Large Telescope, we detected asymmetry in the flux from the Herbig ...Fe star HD 142527 with a barycenter emission situated at a projected separation of 88 + or - 5 mas (12.8 + or - 1.5 AU at 145 pc) and flux ratios in H, K, and L' of 0.016 + or - 0.007, 0.012 + or - 0.008, and 0.0086 + or - 0.0011, respectively (3sigma errors), relative to the primary star and disk. After extensive closure-phase modeling, we interpret this detection as a close-in, low-mass stellar companion with an estimated mass of ~0.1-0.4 M sub(middot in circle). HD 142527 has a complex disk structure, with an inner gap imaged in both the near and mid-IR as well as a spiral feature in the outer disk in the near-IR. This newly detected low-mass stellar companion may provide a critical explanation of the observed disk structure.
Breast cancer and its treatment have been associated with psychological morbidity. In this study our aim was to quantify the excess anxiety and depression resulting from breast cancer. We compared ...538 newly diagnosed breast cancer patients at low risk of recurrence (87.0% responded) to 872 women randomly selected from the Danish general population (69.7% responded) using the Hospital Anxiety and Depression Scale (HADS). Contrary to expectations, the proportions classified as “cases” of anxiety and depression were not significantly different in the two groups. The breast cancer patients’ mean HADS scores were significantly lower than those in the general population sample (anxiety, P = 0.021; depression, P < 0.001), indicating less anxiety and depression. However, we question the validity of this comparison. The HADS may not be suitable for use in the general population and there may be methodological problems in comparisons of groups whose life situations are very different.
Being able to undertake more efficient maintenance and renewal planning of road networks has seen a number of pavement management systems (PMS) being developed between the 80s to mid-90s. During the ...initial years, there was a significant focus on substantiating the need and demonstrating the benefits of using these tools to assist in the investment planning for roads. Today, with substantial experience, and legislative support such as MAP-21 and PASS-55, the use of PMS in the asset management cycle of roads is a given. The challenge these days is to effectively use these tools and ensure robust outcomes are achieved from the overall PMS process. The success of any PMS is determined by a number of factors including having skilled resources, institutional support, and legislative and funding drivers demanding evidence-based forecasted investment needs. Asset managers also realize the importance of having technical robustness in the process to ensure likely outcomes. This paper documents the evolutionary development pathway of the New Zealand PMS that has now been in use across the entire country for more than 18 years. It shows how by always challenging the status quo it has resulted in consistently increasing the overall robustness of the system. In particular, it shows how different validation techniques have been used to improve the practicality and appropriateness of long-term forecasting capabilities.
The young systemsPZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of the new planet finder of the Very Large Telescope (VLT) SPHERE with several imaging ...and spectroscopic modes. We aim to refine the physical properties and architecture of both systems. We use SPHERE commissioning data and dedicated Rapid Eye Mount (REM) observations, as well as literature and unpublished data from VLT/SINFONI, VLT/NaCo, Gemini/NICI, and Keck/NIRC2. We derive new photometry and confirm the short-term (P = 0.94 d) photometric variability of the star PZ Tel A with values of 0.14 and 0.06 mag at optical and near-infrared wavelengths, respectively. SPHERE opens new horizons in the study of young brown dwarfs and giant exoplanets using direct imaging thanks to high-contrast imaging capabilities at optical and near-infrared wavelengths, as well as high signal-to-noise spectroscopy in the near-infrared domain from low resolutions (R ~ 30-50) to medium resolutions (R ~ 350).
Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages (<50 Myr) and atmospheric properties, with temperatures of ...800-1800 K and very red colors (J - H > 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct-imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160160 super(+350) sub(-60) Myr, GJ 504b has an estimated mass of 4 super(+45) sub(-1.0) Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of ~30 AU predicted for the core accretion mechanism. GJ 504b is also significantly cooler (510 super(+30) sub(-20) K) and has a bluer color (J - H = -0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets as well as their atmospheric properties.
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