25 research outputs found

    The IACOB spectroscopic database of Galactic OB stars

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    We present the IACOB spectroscopic database, the largest homogeneous database of high-resolution, high signal-to-noise ratio spectra of Northern Galactic OB-type stars compiled up to date. The spectra were obtained with the FIES spectrograph attached to the Nordic Optical Telescope. We briefly summarize the main characeristics and present status of the IACOB, first scientific results, and some future plans for its extension and scientific exploitation.Comment: 2 pages. Poster contribution to the proceedings of the IAU272 "Active OB stars: structure, evolution, mass loss and critical limits

    Septic embolic encephalitis after Staphylococcus aureus endocarditis of a prosthetic valve in a 57-year-old woman: a case report

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    For prosthetic heart valves the risk of infection is much higher than for native heart valves. During the course of infective endocarditis 20-40% of all patients suffer from cerebrovascular complications such as ischaemic stroke or intracerebral haemorrhage. We present the case of a 57-year-old woman who had undergone surgery to mechanically replace an aortic heart valve 11 months ago and suffered from repeated ischaemic strokes with secondary haemorrhage. The initial antibiotic regimen was ineffective in treating the later diagnosed Staphylococcus aureus infection of the prosthetic valve. Escalation of the antibiotic treatment was not able to halt the clinical course that finally led to the patient’s death. The case report emphasizes the importance of early identification of the aetiology of infection in patients with mechanical heart valve replacement. Without rapid and adequate treatment there is a considerable risk for the development of severe neurological sequelae and cardiac failure that can ultimately result in a fatal course of this clinical picture

    The nature of the Cygnus extreme B supergiant 2MASS J20395358+4222505

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    2MASS J20395358+4222505 is an obscured early B supergiant near the massive OB star association Cygnus OB2. Despite its bright infrared magnitude (Ks = 5.82) it has remained largely ignored because of its dim optical magnitude (B = 16.63, V = 13.68). In a previous paper, we classified it as a highly reddened, potentially extremely luminous, early B-type supergiant. We obtained its spectrum in the U, B and R spectral bands during commissioning observations with the instrument MEGARA at the Gran Telescopio CANARIAS. It displays a particularly strong Hα emission for its spectral type, B1 Ia. The star seems to be in an intermediate phase between supergiant and hypergiant, a group that it will probably join in the near (astronomical) future. We observe a radial velocity difference between individual observations and determine the stellar parameters, obtaining Teff = 24 000 K and log gc = 2.88 ± 0.15. The rotational velocity found is large for a B supergiant, v sin i = 110 ± 25 kms−1⁠. The abundance pattern is consistent with solar, with a mild C underabundance (based on a single line). Assuming that J20395358+4222505 is at the distance of Cyg OB2, we derive the radius from infrared photometry, finding R = 41.2 ± 4.0 R⊙, log(L/L⊙) = 5.71 ± 0.04 and a spectroscopic mass of 46.5 ± 15.0 M⊙. The clumped mass-loss rate (clumping factor 10) is very high for the spectral type, M˙ = 2.4 × 10−6 M⊙ a−1. The high rotational velocity and mass-loss rate place the star at the hot side of the bi-stability jump. Together with the nearly solar CNO abundance pattern, they may also point to evolution in a binary system, J20395358+4222505 being the initial secondary.SS-D and AH acknowledge support from the Spanish Government Ministerio de Ciencia e InnovaciĂłn through grants PGC-2018-091 3741-B-C22 and CEX2019-000920-S and from the Canarian Agency for Research, Innovation and Information Society (ACIISI), of the Canary Islands Government, and the European Regional Development Fund (ERDF), under grant with reference ProID2020010016. MG and FN acknowledge financial support through Spanish grant PID2019-105552RB-C41 (MINECO/MCIU/AEI/FEDER) and from the Spanish State Research Agency (AEI) through the Unidad de Excelencia ‘MarĂ­a de Maeztu’-Centro de AstrobiologĂ­a (CSIC-INTA) project No. MDM-2017-0737. SRB acknowledges support by the Spanish Government under grants AYA2015-68012-C2-2-P and PGC2018-093741-B-C21/C22 (MICIU/AEI/FEDER, UE). SRA acknowledges funding support from the FONDECYT IniciaciĂłn project 11171025 and the FONDECYT Regular project 1201490. JIP acknowledges finantial support from projects Estallidos6 AYA2016-79724-C4 (Spanish Ministerio de Economia y Competitividad), Estallidos7 PID2019-107408GB-C44 (Spanish Ministerio de Ciencia e Innovacion), grant P18-FR-2664 (Junta de AndalucĂ­a), and grant SEV-2017-0709 ‘Centro de Excelencia Severo Ochoa Program’ (Spanish Science Ministry). AGP, SP, AG-M, JG and NC acknowledge support from the Spanish MCI through project RTI2018-096188-B-I00

    The Effective Temperatures of Hot Stars II. The Early-O Types

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    We derive the stellar parameters of a sample of Galactic early-O type stars by analysing their UV and Far-UV spectra from FUSE (905-1187A), IUE, HST-STIS and ORFEUS (1200-2000A). The data have been modeled with spherical, hydrodynamic, line-blanketed, non-LTE synthetic spectra computed with the WM-basic code. We obtain effective temperatures ranging from Teff = 41,000 K to 39,000 K for the O3-O4 dwarf stars, and Teff = 37,500 K for the only supergiant of the sample (O4 If+). Our values are lower than those from previous empirical calibrations for early-O types by up to 20%. The derived luminosities of the dwarf stars are also lower by 6 to 12%; however, the luminosity of the supergiant is in agreement with previous calibrations within the error bars. Our results extend the trend found for later-O types in a previous work by Bianchi & Garcia.Comment: Accepted for publication in The Astrophysical Journal. 38 pages (including 9 figures and 4 tables

    Insights into permanent pacemaker implantation following TAVR in a real-world cohort.

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    BACKGROUND:Permanent pacemaker implantation (PPI) following TAVR is a frequent post interventional complication and its management remains controversial. OBJECTIVE:We sought to elucidate the electrophysiological, procedural, and clinical baseline parameters that are associated with and perhaps predict the need for PPI after TAVR in a heterogeneous-valve-type real-world cohort. METHODS:Overall, 494 patients receiving TAVR at our center from April 2009 to August 2015 were screened. ECG analyses and clinical parameters were collected prospectively. RESULTS:Overall, 401 patients in this all-comers real-world TAVR cohort with a PPI rate of 16% were included. The mean age was 82 years, and the mean duration to PPI was 5.5 days. A large proportion of Edwards SAPIEN valves (81%), DirectFlow, CoreValve, and Portico were implanted. The main indications for PPI were atrioventricular (AV) block III, AV-block Mobitz type II, bradycardic atrial fibrillation and persistent sinus bradycardia. Between groups with and without PPI, significant differences were noted in the prevalence of post TAVR balloon dilatation, resting heart rate, QRS interval, PR interval with a cut-off of >178 ms, left anterior fascicular block and RBBB in univariate analyses. In the subsequent multiple regression analysis, post TAVR balloon dilatation and a PR interval with a cut-off of >178 ms were significant predictors of PPI. CONCLUSION:This real-world cohort differs from others in its size and heterogeneous valve selection, and indicates for the first time that patients with post balloon dilatation or prolonged PR interval are at a higher risk for pacemaker dependency after TAVR
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