Dynamical detection of a companion driving a spiral arm in a protoplanetary disk

Radio and near-infrared observations have observed dozens of protoplanetary disks that host spiral arm features. Numerical simulations have shown that companions may excite spiral density waves in protoplanetary disks via companion-disk interaction. However, the lack of direct observational evidence for spiral-driving companions poses challenges to current theories of companion-disk interaction. Here we report multi-epoch observations of the binary system HD 100453 with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) facility at the Very Large Telescope. By recovering the spiral features via robustly removing starlight contamination, we measure spiral motion across 4 yr to perform dynamical motion analyses. The spiral pattern motion is consistent with the orbital motion of the eccentric companion. With this first observational evidence of a companion driving a spiral arm among protoplanetary disks, we directly and dynamically confirm the long-standing theory on the origin of spiral features in protoplanetary disks. With the pattern motion of companion-driven spirals being independent of companion mass, here we establish a feasible way of searching for hidden spiral-arm-driving planets that are beyond the detection of existing ground-based high-contrast imagers.Comment: Accepted for publication in Astronomy and Astrophysics; 12 pages, 9 figure

HST survey of the Orion Nebula Cluster in the H2_2O 1.4 μ\mum absorption band: I. A census of substellar and planetary mass objects

In order to obtain a complete census of the stellar and sub-stellar population, down to a few M$_{Jup}$ in the $\sim1$ Myr old Orion Nebula Cluster, we used the infrared channel of the Wide Field Camera 3 of the Hubble Space Telescope with the F139M and F130N filters. These bandpasses correspond to the $1.4 \mu$m H$_2$O absorption feature and an adjacent line-free continuum region. Out of $4,504$ detected sources, $3,352$ (about $75\%$) appear fainter than m$_{130}=14$ (Vega mag) in the F130N filter, a brightness corresponding to the hydrogen-burning limit mass (M$\simeq 0.072 M_\odot$) at $\sim 1$ Myr. Of these, however, only $742$ sources have a negative F130M-139N color index, indicative of the presence of H$_2$O vapor in absorption, and can therefore be classified as bona-fide M and L dwarfs, with effective temperatures T$\lesssim 2850$ K at an assumed $1$ Myr cluster age. On our color-magnitude diagram, this population of sources with H$_2$O absorption appears clearly distinct from the larger background population of highly reddened stars and galaxies with positive F130M-F139N color index, and can be traced down to the sensitivity limit of our survey, m$_{130}\simeq 21.5$, corresponding to a $1$ Myr old $\simeq 3$M$_{Jup}$, planetary mass object under about 2 magnitudes of visual extinction. Theoretical models of the BT-Settl family predicting substellar isochrones of $1, 2$ and $3$ Myr (down to $\sim 1$M$_{Jup}$) fail to reproduce the observed H$_2$O color index at M$\lesssim 20$M$_{Jup}$. We perform a Bayesian analysis to determine extinction, mass and effective temperature of each sub-stellar member of our sample, together with its membership probability.Comment: Accepted for publication in the Astrophysical Journal. The resolution of several figures has been downgraded to comply with the size limit of arXiv submission

HST Survey of the Orion Nebula Cluster in the H₂O 1.4 μm Absorption Band. I. A Census of Substellar and Planetary-mass Objects

In order to obtain a complete census of the stellar and substellar population, down to a few M_(Jup) in the ~1 Myr old Orion Nebula Cluster, we used the infrared channel of the Wide Field Camera 3 of the Hubble Space Telescope with the F139M and F130N filters. These bandpasses correspond to the 1.4 μm H₂O absorption feature and an adjacent line-free continuum region. Out of 4504 detected sources, 3352 (about 75%) appear fainter than m₁₃₀ = 14 (Vega mag) in the F130N filter, a brightness corresponding to the hydrogen-burning limit mass M ≃ 0.072 M_⊙) at ~1 Myr. Of these, however, only 742 sources have a negative F130M–F139N color index, indicative of the presence of H₂O vapor in absorption, and can therefore be classified as bona fide M and L dwarfs, with effective temperatures T ≾ 2850 K at an assumed 1 Myr cluster age. On our color–magnitude diagram (CMD), this population of sources with H₂O absorption appears clearly distinct from the larger background population of highly reddened stars and galaxies with positive F130M–F139N color index and can be traced down to the sensitivity limit of our survey, m₁₃₀ ≃ 21.5, corresponding to a 1 Myr old ≃ 3 M_(Jup) planetary-mass object under about 2 mag of visual extinction. Theoretical models of the BT-Settl family predicting substellar isochrones of 1, 2, and 3 Myr down to ~1 M_(Jup) fail to reproduce the observed H₂O color index at M ≾ 20 M_(Jup). We perform a Bayesian analysis to determine extinction, mass, and effective temperature of each substellar member of our sample, together with its membership probability

Dynamical detection of a companion driving a spiral arm in a protoplanetary disk

Accepted for publication in Astronomy and Astrophysics; 12 pages, 9 figuresInternational audienceRadio and near-infrared observations have observed dozens of protoplanetary disks that host spiral arm features. Numerical simulations have shown that companions may excite spiral density waves in protoplanetary disks via companion-disk interaction. However, the lack of direct observational evidence for spiral-driving companions poses challenges to current theories of companion-disk interaction. Here we report multi-epoch observations of the binary system HD 100453 with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) facility at the Very Large Telescope. By recovering the spiral features via robustly removing starlight contamination, we measure spiral motion across 4 yr to perform dynamical motion analyses. The spiral pattern motion is consistent with the orbital motion of the eccentric companion. With this first observational evidence of a companion driving a spiral arm among protoplanetary disks, we directly and dynamically confirm the long-standing theory on the origin of spiral features in protoplanetary disks. With the pattern motion of companion-driven spirals being independent of companion mass, here we establish a feasible way of searching for hidden spiral-arm-driving planets that are beyond the detection of existing ground-based high-contrast imagers

Dynamical detection of a companion driving a spiral arm in a protoplanetary disk

Accepted for publication in Astronomy and Astrophysics; 12 pages, 9 figuresInternational audienceRadio and near-infrared observations have observed dozens of protoplanetary disks that host spiral arm features. Numerical simulations have shown that companions may excite spiral density waves in protoplanetary disks via companion-disk interaction. However, the lack of direct observational evidence for spiral-driving companions poses challenges to current theories of companion-disk interaction. Here we report multi-epoch observations of the binary system HD 100453 with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) facility at the Very Large Telescope. By recovering the spiral features via robustly removing starlight contamination, we measure spiral motion across 4 yr to perform dynamical motion analyses. The spiral pattern motion is consistent with the orbital motion of the eccentric companion. With this first observational evidence of a companion driving a spiral arm among protoplanetary disks, we directly and dynamically confirm the long-standing theory on the origin of spiral features in protoplanetary disks. With the pattern motion of companion-driven spirals being independent of companion mass, here we establish a feasible way of searching for hidden spiral-arm-driving planets that are beyond the detection of existing ground-based high-contrast imagers

Dynamical detection of a companion driving a spiral arm in a protoplanetary disk

Accepted for publication in Astronomy and Astrophysics; 12 pages, 9 figuresInternational audienceRadio and near-infrared observations have observed dozens of protoplanetary disks that host spiral arm features. Numerical simulations have shown that companions may excite spiral density waves in protoplanetary disks via companion-disk interaction. However, the lack of direct observational evidence for spiral-driving companions poses challenges to current theories of companion-disk interaction. Here we report multi-epoch observations of the binary system HD 100453 with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) facility at the Very Large Telescope. By recovering the spiral features via robustly removing starlight contamination, we measure spiral motion across 4 yr to perform dynamical motion analyses. The spiral pattern motion is consistent with the orbital motion of the eccentric companion. With this first observational evidence of a companion driving a spiral arm among protoplanetary disks, we directly and dynamically confirm the long-standing theory on the origin of spiral features in protoplanetary disks. With the pattern motion of companion-driven spirals being independent of companion mass, here we establish a feasible way of searching for hidden spiral-arm-driving planets that are beyond the detection of existing ground-based high-contrast imagers

Deep learning-based segmentation of prostatic urethra on computed tomography scans for treatment planning

International audienceBACKGROUND AND PURPOSE: The intraprostatic urethra is an organ at risk in prostate cancer radiotherapy, but its segmentation in computed tomography (CT) is challenging. This work sought to: i) propose an automatic pipeline for intraprostatic urethra segmentation in CT, ii) analyze the dose to the urethra, iii) compare the predictions to magnetic resonance (MR) contours. MATERIALS AND METHODS: First, we trained Deep Learning networks to segment the rectum, bladder, prostate, and seminal vesicles. Then, the proposed Deep Learning Urethra Segmentation model was trained with the bladder and prostate distance transforms and 44 labeled CT with visible catheters. The evaluation was performed on 11 datasets, calculating centerline distance (CLD) and percentage of centerline within 3.5 and 5 mm. We applied this method to a dataset of 32 patients treated with intensity-modulated radiation therapy (IMRT) to quantify the urethral dose. Finally, we compared predicted intraprostatic urethra contours to manual delineations in MR for 15 patients without catheter. RESULTS: A mean CLD of 1.6 ± 0.8 mm for the whole urethra and 1.7 ± 1.4, 1.5 ± 0.9, and 1.7 ± 0.9 mm for the top, middle, and bottom thirds were obtained in CT. On average, 94% and 97% of the segmented centerlines were within a 3.5 mm and 5 mm radius, respectively. In IMRT, the urethra received a higher dose than the overall prostate. We also found a slight deviation between the predicted and manual MR delineations. CONCLUSION: A fully-automatic segmentation pipeline was validated to delineate the intraprostatic urethra in CT images

External or internal companion exciting the spiral arms in CQ Tau?

International audienceWe present new high-contrast images in near-infrared wavelengths (λc = 1.04, 1.24, 1.62, 2.18, and 3.78 μm) of the young variable star CQ Tau, aiming to constrain the presence of companions in the protoplanetary disc. We reached a Ks-band contrast of 14 mag with SPHERE/IRDIS at separations greater than 0${_{.}^{\prime\prime}}$4 from the star. Our mass sensitivity curve rules out giant planets above 4 MJup immediately outside the spiral arms at ~60 au and above 2-3 MJup beyond 100 au to 5σ confidence assuming hot-start models. We do, however, detect four spiral arms, a double-arc and evidence for shadows in scattered light cast by a misaligned inner disc. Our observations may be explained by an unseen close-in companion on an inclined and eccentric orbit. Such a hypothesis would also account for the disc CO cavity and disturbed kinematics