Spectroscopic analysis in the virtual observatory environment with SPLAT-VO

Škoda, Petr; Draper, P. W.; Neves, Margarida Castro; Andrešič, David; Jenness, Tim

doi:10.1016/j.ascom.2014.06.001

Cited by 18 publications

(8 citation statements)

References 24 publications

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“…We downloaded the far-UV 1150-1900 Å (SWP camera) and near-UV 2000-3300 Å (LWP and LWR cameras) lowdispersion large-aperture fluxes of B[e] stars from the INES database using the SPLAT-VO package (Draper 2014(Draper , Škoda et al 2014. We selected only B[e] stars with multiple IUE observations that are suitable for the analysis of variability.…”

Section: Methodsmentioning

confidence: 99%

An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes

Krtičková

Krtička

2018

Monthly Notices of the Royal Astronomical Society

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Stars with B[e] phenomenon comprise a very diverse group of objects in a different evolutionary status. These objects show common spectral characteristics, including presence of Balmer lines in emission, forbidden lines, and strong infrared excess due to the dust. The observations of emission lines indicate the illumination by ultraviolet ionizing source, which is a key part to understand the elusive nature of these objects. We study the ultraviolet variability of many B[e] stars to specify the geometry of the circumstellar environment and its variability. We analyse massive hot B[e] stars from our Galaxy and from Magellanic Clouds. We study the ultraviolet broad-band variability derived from the flux-calibrated data. We determine variations of individual lines and its correlation with the total flux variability. We detected variability of the spectral energy distribution and of the line profiles. The variability has several sources of origin, including the light absorption by the disk, pulsations, LBV-type variations, and eclipses in the case of binaries. The stellar radiation of most of B[e] stars is heavily obscured by circumstellar material. This suggests that the circumstellar material is not present only in the disk but also above its plane. The flux and line variability is consistent with a two-component model of circumstellar environment composed of the dense disk and ionized envelope. The observations of B[e] supergiants show that many of these stars have nearly the same luminosity of about 1.9 × 10 5 L ⊙ and similar effective temperature.

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Section: Methodsmentioning

confidence: 99%

An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes

Krtičková

Krtička

2018

Monthly Notices of the Royal Astronomical Society

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“…Contrary to barium, other s-and r-process chemical elements (except yttrium), show a slight underabundance com- pared to other stars of this cluster. However, NGC 5316 31 does not fall into a category of barium-rich stars as defined by de Castro et al (2016). Dias et al (2001) give an 86% probability for this star being a member of NGC 5316.…”

Section: Neutron-capture Elementsmentioning

confidence: 97%

Chemical composition of evolved stars in the young open clusters NGC 4609 and NGC 5316

Drazdauskas

Tautvaišienė

Smiljanić

et al. 2016

Mon. Not. R. Astron. Soc.

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High-resolution spectral analysis is performed for the first time in evolved stars of two young open clusters: NGC 4609 and NGC 5316, of about 80 and 100 Myr in age, respectively, and turn-off masses above 5 M ⊙ . Stellar evolution models predict an extra-mixing event in evolved stars, which follows the first dredge-up and happens later on the red giant branch. However, it is still not understood how this process affects stars of different masses. In this study, we determine abundances of the mixing sensitive elements carbon and nitrogen, carbon isotope 12 C/ 13 C ratios, as well as 20 other elements produced by different nucleosynthetic processes (O, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Y, Zr, Ba, La, Ce, Pr, Nd, and Eu). We compared our results with the latest theoretical models of evolutionary mixing processes. We find that the obtained 12 C/ 13 C and C/N ratios and [Na/Fe] agree quite well with the model which takes into account thermohaline-and rotation-induced mixing but within error limits also agree with the standard first dredge-up model. Comparison of oxygen, magnesium and other α-elements with theoretical models of Galactic chemical evolution revealed that both clusters follow the thin disk α-element trends. Neutron-capture element abundances in NGC 4609 are apparently reflecting its birthplace in the thin disk, while NGC 5316 has marginally higher abundances, which would indicate its birthplace in an environment more enriched with neutron-capture elements.

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“…The reduction was all performed offline, within the Starlink Project software suite 38 . The manipulation of timestream data used KAPPA 39 , the cube was made in SMURF 40 , and the final spectra were constructed in SPLAT 41 . The software is open access and is supported by the East Asian Observatory.…”

Section: Jcmt Data Reductionmentioning

confidence: 99%

Phosphine gas in the cloud decks of Venus

et al. 2020

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Measurements of trace gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbour, Venus, has cloud decks that are temperate but hyperacidic. Here we report the apparent presence of phosphine (PH 3) gas in Venus's atmosphere, where any phosphorus should be in oxidized forms. Single-line millimetre-waveband spectral detections (quality up to ~15σ) from the JCMT and ALMA telescopes have no other plausible identification. Atmospheric PH 3 at ~20 ppb abundance is inferred. The presence of PH 3 is unexplained after exhaustive study of steady-state chemistry and photochemical pathways, with no currently known abiotic production routes in Venus's atmosphere, clouds, surface and subsurface, or from lightning, volcanic or meteoritic delivery. PH 3 could originate from unknown photochemistry or geochemistry, or, by analogy with biological production of PH 3 on Earth, from the presence of life. Other PH 3 spectral features should be sought, while in situ cloud and surface sampling could examine sources of this gas.

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Spectroscopic analysis in the virtual observatory environment with SPLAT-VO

Cited by 18 publications

References 24 publications

An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes

An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes

Chemical composition of evolved stars in the young open clusters NGC 4609 and NGC 5316

Phosphine gas in the cloud decks of Venus

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