73 research outputs found
Ectodermal Dysplasia with Amastia: A Case of One-Step Reconstruction
Background. Female patients presenting amastia associated with ectodermal dysplasia are not frequently encountered, but they are of great clinical interest and surgically demanding. Traditionally, skin alterations related to Ectodermal Dysplasia have addressed plastic surgeons to perform a two-stage approach in amastia associated with this congenital pathologic condition. This article describes an alternative method for correcting this deformity trough a mammary reconstruction in one surgical stage. Materials and Methods. We report a case of 26-year-old female patient with bilateral amastia associated with ectodermal dysplasia. Amastia in this patient was treated with implantation of subpectoral silicone gel prostheses, without previously breast tissue expansion. Results. At 18 months of follow-up after surgey, there were no complications and excellent cosmetic results were achieved. Patient and surgeon satisfaction was high and the patient underwent a bilateral areola-tattoo. Conclusions. One-stage mammary reconstruction have showed to be a reliable and effective technique also when amastia is associated with Ectodermal Dysplasia, suggesting a still satisfying biomechanical performance of the skin in this pathology
The Depletion of Water During Dispersal of Planet-forming Disk Regions
We present a new velocity-resolved survey of 2.9 μm spectra of hot H_2O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R ~ 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9–33 μm that probe from the dust sublimation radius at ~0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H_2O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 μm spectra (R_(co)), which probes molecular gaps in inner disks. We find that H_2O emission disappears from 2.9 μm (hotter water) to 33 μm (colder water) as R_(co) increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars of M⋆ > 1.5 M⊙ generally have inner gaps with depleted molecular gas content. We measure radial trends in H_2O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05–20 au. We propose that JWST spectroscopy of molecular gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA
The Depletion of Water During Dispersal of Planet-forming Disk Regions
We present a new velocity-resolved survey of 2.9 μm spectra of hot H_2O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R ~ 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9–33 μm that probe from the dust sublimation radius at ~0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H_2O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 μm spectra (R_(co)), which probes molecular gaps in inner disks. We find that H_2O emission disappears from 2.9 μm (hotter water) to 33 μm (colder water) as R_(co) increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars of M⋆ > 1.5 M⊙ generally have inner gaps with depleted molecular gas content. We measure radial trends in H_2O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05–20 au. We propose that JWST spectroscopy of molecular gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA
Candidate Water Vapor Lines to Locate the H2O Snowline through High-dispersion Spectroscopic Observations. III. Submillimeter H2 16O and H2 18O Lines
In this paper, we extend the results presented in our former papers on using ortho-H216O line profiles to constrain the location of the H2O snowline in T Tauri and Herbig Ae disks, to include submillimeter para-H216O and ortho- and para-H218O lines. Since the number densities of the ortho- and para-H218O molecules are about 560 times smaller than their 16O analogs, they trace deeper into the disk than the ortho-H216O lines (down to z = 0, i.e., the midplane). Thus these H218O lines are potentially better probes of the position of the H2O snowline at the disk midplane, depending on the dust optical depth. The values of the Einstein A coefficients of submillimeter candidate water lines tend to be lower (typically <10‑4 s‑1) than infrared candidate water lines. Thus in the submillimeter candidate water line cases, the local intensity from the outer optically thin region in the disk is around 104 times smaller than that in the infrared candidate water line cases. Therefore, in the submillimeter lines, especially H218O and para-H216O lines with relatively lower upper state energies (∼a few 100 K) can also locate the position of the H2O snowline. We also investigate the possibility of future observations with ALMA to identify the position of the water snowline. There are several candidate water lines that trace the hot water gas inside the H2O snowline in ALMA Bands 5–10
A UV-to-NIR Study of Molecular Gas in the Dust Cavity around RY Lupi
We present a study of molecular gas in the inner disk (r ∼ 0.4± 0.1 au; {r(narrow,H₂)} ∼ 3± 2 au). The 4.7 μm ¹²CO emission lines are also well fit by two-component profiles ( {{r}broad,CO} =0.4± 0.1 au; {{r}narrow,CO} =15± 2 au). We combine these results with 10 μm observations to form a picture of gapped structure within the mm-imaged dust cavity, providing the first such overview of the inner regions of a young disk. The HST SED of RY Lupi is available online for use in modeling efforts
Brightness and mass accretion rate evolution during the 2022 burst of EX~Lupi
EX Lupi is the prototype by which EXor-type outbursts were defined. It has experienced multiple accretion-related bursts and outbursts throughout the last decades, whose study have greatly extended our knowledge about the effects of these types of events. This star experienced a new burst in 2022. We used multi-band photometry to create color-color and color-magnitude diagrams to exclude the possibility that the brightening could be explained by a decrease in extinction. We obtained VLT/X-shooter spectra to determine the Lacc and Macc during the peak of the burst and after its return to quiescence using 2 methods: empirical relationships between line luminosity and Lacc, and a slab model of the whole spectrum. We examined the 130 year light curve of EX Lupi to provide statistics on the number of outbursts experienced during this period of time. Our analysis of the data taken during the 2022 burst confirmed that a change in extinction is not responsible for the brightening. Our two approaches in calculating the Macc were in agreement, and resulted in values that are 2 orders of magnitude above what had previously been estimated, thus suggesting that EX Lupi is a strong accretor even when in quiescence. We determined that in 2022 March the Macc increased by a factor of 7 with respect to the quiescent level. We also found hints that even though the Macc had returned to almost its pre-outburst levels, certain physical properties of the gas had not returned to the quiescent values. We found that the mass accreted during this three month event was 0.8 lunar masses, which is approximately half of what is accreted during a year of quiescence. We calculated that if EX Lupi remains as active as it has been for the past 130 years, during which it has experienced at least 3 outbursts and 10 bursts, then it will deplete the mass of its circumstellar material in less than 160000 yr
Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers
We present a review of the interplay between the evolution of circumstellar
disks and the formation of planets, both from the perspective of theoretical
models and dedicated observations. Based on this, we identify and discuss
fundamental questions concerning the formation and evolution of circumstellar
disks and planets which can be addressed in the near future with optical and
infrared long-baseline interferometers. Furthermore, the importance of
complementary observations with long-baseline (sub)millimeter interferometers
and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics
Review"; The final publication is available at http://www.springerlink.co
Magnetically gated accretion in an accreting ‘non-magnetic’ white dwarf
White dwarfs are often found in binary systems with orbital periods ranging from tens of minutes to hours in which they can accrete gas from their companion stars. In about 15 per cent of these binaries, the magnetic field of the white dwarf is strong enough (at 106 gauss or more) to channel the accreted matter along field lines onto the magnetic poles1,2. The remaining systems are referred to as ‘non-magnetic’, because until now there has been no evidence that they have a magnetic field that is strong enough to affect the accretion dynamics. Here we report an analysis of archival optical observations of the ‘non-magnetic’ accreting white dwarf in the binary system MV Lyrae, whose light curve displays quasi-periodic bursts of about 30 minutes duration roughly every 2 hours. The timescale and amplitude of these bursts indicate the presence of an unstable, magnetically regulated accretion mode, which in turn implies the existence of magnetically gated accretion3,4,5, in which disk material builds up around the magnetospheric boundary (at the co-rotation radius) and then accretes onto the white dwarf, producing bursts powered by the release of gravitational potential energy. We infer a surface magnetic field strength for the white dwarf in MV Lyrae of between 2 × 104 gauss and 1 × 105 gauss, too low to be detectable by other current methods. Our discovery provides a new way of studying the strength and evolution of magnetic fields in accreting white dwarfs and extends the connections between accretion onto white dwarfs, young stellar objects and neutron stars, for which similar magnetically gated accretion cycles have been identified6,7,8,9
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