Beyond Speculative Robot Ethics

In this article we develop a dialogue model for robot technology experts and designated users to discuss visions on the future of robotics in long-term care. Our vision assessment study aims for more distinguished and more informed visions on future robots. Surprisingly, our experiment also lead to some promising co-designed robot concepts in which jointly articulated moral guidelines are embedded. With our model we think to have designed an interesting response on a recent call for a less speculative ethics of technology by encouraging discussions about the quality of positive and negative visions on the future of robotics.

Observability of Forming Planets and their Circumplanetary Disks I. -- Parameter Study for ALMA

We present mock observations of forming planets with ALMA. The possible detections of circumplanetary disks (CPDs) were investigated around planets of Saturn, 1, 3, 5, and 10 Jupiter-masses that are placed at 5.2 AU from their star. The radiative, three dimensional hydrodynamic simulations were then post-processed with RADMC3D and the ALMA Observation Simulator. We found that even though the CPDs are too small to be resolved, they are hot due to the accreting planet in the optically thick limit, therefore the best chance to detect them with continuum observations in this case is at the shortest ALMA wavelengths, such as Band 9 (440 microns). Similar fluxes were found in the case of Saturn and Jupiter-mass planets, as for the 10 $\mathrm{M_{Jup}}$ gas-giant, due to temperature weighted optical depth effects: when no deep gap is carved, the planet region is blanketed by the optically thick circumstellar disk leading to a less efficient cooling there. A test was made for a 52 AU orbital separation, showed that optically thin CPDs are also detectable in band 7 but they need longer integration times ($>$5hrs). Comparing the gap profiles of the same simulation at various ALMA bands and the hydro simulation confirmed that they change significantly, first because the gap is wider at longer wavelengths due to decreasing optical depth; second, the beam convolution makes the gap shallower and at least 25% narrower. Therefore, caution has to be made when estimating planet masses based on ALMA continuum observations of gaps.Comment: Accepted for publication at MNRAS. Typos are corrected since previous version. 11 pages, 5 tables, 4 figure

CO ro-vibrational lines in HD100546: A search for disc asymmetries and the role of fluorescence

We have studied the emission of CO ro-vibrational lines in the disc around the Herbig Be star HD100546 with the final goal of using these lines as a diagnostic to understand inner disc structure in the context of planet formation. High-resolution IR spectra of CO ro-vibrational emission at eight different position angles were taken with CRIRES at the VLT. From these spectra flux tables, CO ro-vibrational line profiles, and population diagrams were produced. We have investigated variations in the line profile shapes and line strengths as a function of slit position angle. We used the thermochemical disc modelling code ProDiMo based on the chemistry, radiation field, and temperature structure of a previously published model for HD100546. Comparing observations and the model, we investigated the possibility of disc asymmetries, the excitation mechanism (UV fluorescence), the geometry, and physical conditions of the inner disc. The observed CO ro-vibrational lines are largely emitted from the inner rim of the outer disc at 10-13 AU. The line shapes are similar for all v levels and line fluxes from all vibrational levels vary only within one order of magnitude. All line profile asymmetries and variations can be explained with a symmetric disc model to which a slit correction and pointing offset is applied. Because the angular size of the CO emitting region (10-13 AU) and the slit width are comparable the line profiles are very sensitive to the placing of the slit. The model reproduces the line shapes and the fluxes of the v=1-0 lines as well as the spatial extent of the CO ro-vibrational emission. It does not reproduce the observed band ratios of 0.5-0.2 with higher vibrational bands. We find that lower gas volume densities at the surface of the inner rim of the outer disc can make the fluorescence pumping more effcient and reproduce the observed band ratios.Comment: 20 pages, 21 figure

Dust masses of disks around 8 Brown Dwarfs and Very Low-Mass Stars in Upper Sco OB1 and Ophiuchus

We present the results of ALMA band 7 observations of dust and CO gas in the disks around 7 objects with spectral types ranging between M5.5 and M7.5 in Upper Scorpius OB1, and one M3 star in Ophiuchus. We detect unresolved continuum emission in all but one source, and the $^{12}$CO J=3-2 line in two sources. We constrain the dust and gas content of these systems using a grid of models calculated with the radiative transfer code MCFOST, and find disk dust masses between 0.1 and 1 M$_\oplus$, suggesting that the stellar mass / disk mass correlation can be extrapolated for brown dwarfs with masses as low as 0.05 M$_\odot$. The one disk in Upper Sco in which we detect CO emission, 2MASS J15555600, is also the disk with warmest inner disk as traced by its H - [4.5] photometric color. Using our radiative transfer grid, we extend the correlation between stellar luminosity and mass-averaged disk dust temperature originally derived for stellar mass objects to the brown dwarf regime to $\langle T_{dust} \rangle \approx 22 (L_{*} /L_{\odot})^{0.16} K$, applicable to spectral types of M5 and later. This is slightly shallower than the relation for earlier spectral type objects and yields warmer low-mass disks. The two prescriptions cross at 0.27 L$_\odot$, corresponding to masses between 0.1 and 0.2 M$_\odot$ depending on age.Comment: 9 pages,6 figures, accepted to ApJ on 26/01/201

An Inner Gaseous Disk around the Herbig Be Star MWC 147

We present high-spectral-resolution, optical spectra of the Herbig Be star MWC 147, in which we spectrally resolve several emission lines, including the [O I] lines at 6300 and 6363\deg. Their highly symmetric, double-peaked line profiles indicate that the emission originates in a rotating circumstellar disk. We deconvolve the Doppler-broadened [O I] emission lines to obtain a measure of emission as a function of distance from the central star. The resulting radial surface brightness profiles are in agreement with a disk structure consisting of a flat, inner, gaseous disk and a flared, outer, dust disk. The transition between these components at 2 to 3 AU corresponds to the estimated dust sublimation radius. The width of the double-peaked Mg II line at 4481\deg suggests that the inner disk extends to at least 0.10 AU, close to the corotation radius.Comment: accepted for ApJ Letters (Oct. 2010

The Taurus Boundary of Stellar/Substellar (TBOSS) Survey II. Disk Masses from ALMA Continuum Observations

We report 885$\mu$m ALMA continuum flux densities for 24 Taurus members spanning the stellar/substellar boundary, with spectral types from M4 to M7.75. Of the 24 systems, 22 are detected at levels ranging from 1.0-55.6 mJy. The two non-detections are transition disks, though other transition disks in the sample are detected. Converting ALMA continuum measurements to masses using standard scaling laws and radiative transfer modeling yields dust mass estimates ranging from $\sim$0.3-20M$_{\oplus}$. The dust mass shows a declining trend with central object mass when combined with results from submillimeter surveys of more massive Taurus members. The substellar disks appear as part of a continuous sequence and not a distinct population. Compared to older Upper Sco members with similar masses across the substellar limit, the Taurus disks are brighter and more massive. Both Taurus and Upper Sco populations are consistent with an approximately linear relationship in $M_{dust}$ to $M_{star}$, although derived power-law slopes depend strongly upon choices of stellar evolutionary model and dust temperature relation. The median disk around early M-stars in Taurus contains a comparable amount of mass in small solids as the average amount of heavy elements in Kepler planetary systems on short-period orbits around M-dwarf stars, with an order of magnitude spread in disk dust mass about the median value. Assuming a gas:dust ratio of 100:1, only a small number of low-mass stars and brown dwarfs have a total disk mass amenable to giant planet formation, consistent with the low frequency of giant planets orbiting M-dwarfs.Comment: 41 pages and 32 figures, with all tables and appendices presented here in their entirety. Accepted for publication in AJ (November 26, 2017

Warm gas at 50 AU in the disk around Herbig Be star HD 100546

The disk atmosphere is one of the fundamental elements of theoretical models of a protoplanetary disk. However, the direct observation of the warm gas (>> 100 K) at large radius of a disk (>> 10 AU) is challenging, because the line emission from warm gas in a disk is usually dominated by the emission from an inner disk. Our goal is to detect the warm gas in the disk atmosphere well beyond 10 AU from a central star in a nearby disk system of the Herbig Be star HD 100546. We measured the excitation temperature of the vibrational transition of CO at incremental radii of the disk from the central star up to 50 AU, using an adaptive optics system combined with the high-resolution infrared spectrograph CRIRES at the VLT. The observation successfully resolved the line emission with 0".1 angular resolution, which is 10 AU at the distance of HD 100546. Population diagrams were constructed at each location of the disk, and compared with the models calculated taking into account the optical depth effect in LTE condition. The excitation temperature of CO is 400-500 K or higher at 50 AU away from the star, where the blackbody temperature in equilibrium with the stellar radiation drops as low as 90 K. This is unambiguous evidence of a warm disk atmosphere far away from the central star.Comment: 7 pages, 5 figures, A&A in pres