Abstract:This paper characterizes the carbonization process in terms of the utilization of distillery waste in a laboratory-scale reactor. Due to the increase in market prices of wood and environmental protection laws, biomass waste, including distillery waste, is a potential source for biochar production. An experimental investigation of the carbonization process was carried out for different mixtures of distillery waste and oak sawdust. The obtained results showed that due to the European Standard, biochar from disti… Show more
“…10) further confirms the absence of a photospheric chemical depletion. Therefore, we dismiss the possibility of an s -process enrichment following a chemical depletion. Figure 11. Wise colour-colour diagram for the target stars along with the stars studied in Kluska et al (2022). The dashed black lines represent the boundaries between the different categories defined in Kluska et al (2022).…”
Section: Discussionmentioning
confidence: 99%
“…Therefore, we dismiss the possibility of an s -process enrichment following a chemical depletion. Figure 11. Wise colour-colour diagram for the target stars along with the stars studied in Kluska et al (2022). The dashed black lines represent the boundaries between the different categories defined in Kluska et al (2022). The targets of this study are given in magenta colour and are numbered according to their position in Table 1 for reference.…”
Section: Discussionmentioning
confidence: 99%
“…Wise colour-colour diagram for the target stars along with the stars studied in Kluska et al (2022). The dashed black lines represent the boundaries between the different categories defined in Kluska et al (2022).…”
Section: Discussionmentioning
confidence: 99%
“…We adopted the same approach described in Kluska et al (2022) and Kamath et al (2022) to construct all the SEDs in this study. In summary, we began by determining the total line-of-sight reddening or extinction parameter () by minimising the difference between the optical fluxes and the reddened photospheric models.…”
Section: Photometric Analysismentioning
confidence: 99%
“…Observational studies have now firmly established that the presence of the stable compact disc (circumbinary disc) around the disc-sources is attributed to their binary nature (e.g. Van Winckel et al 2009; Oomen et al 2018; Kluska et al 2022).…”
Post-asymptotic giant branch stars (post-AGB) in binary systems, with typical orbital periods between ∼100 to ∼1000 days, result from a poorly understood interaction that terminates their precursory AGB phase. The majority of these binaries display a photospheric anomaly called ‘chemical depletion’, thought to arise froman interaction between the circumbinary disc and the post-AGB star, leading to the reaccretion of pure gas onto the star, devoid of refractory elements due to dust formation. In this paper, we focus on a subset of chemically peculiar binary post-AGBs in the Galaxy and the Magellanic Clouds (MCs). Our detailed stellar parameter and chemical abundance analysis utilising high-resolution optical spectra from VLT+UVES revealed that our targets span a Teff of 4900 - 7250K and [Fe/H] of -0.5 - -1.57 dex. Interestingly, these targets exhibit a carbon ([C/Fe] ranging from 0.5 - 1.0 dex, dependant on metallicity) and s-process enrichment ([s/Fe]≥1dex) contrary to the commonly observed chemical depletion pattern. Using spectral energy distribution (SED) fitting and period-luminosity-colour (PLC) relation methods, we determine the luminosity of the targets (2700 – 8300 L⊙), which enables confirmation of their evolutionary phase and estimation of initial masses (as a function of metallicity) (1 - 2.5M⊙). In conjunction with predictions from dedicated ATON stellar evolutionary models, our results indicate a predominant intrinsic enrichment of carbon and s-process elements in our binary post-AGB targets. We qualitatively rule out extrinsic enrichment and inherited s-process enrichment from the host galaxy as plausible explanations for the observed overabundances. Our chemically peculiar subset of intrinsic carbon and s-process enriched binary post-AGBs also hints at potential variation in the efficiency of chemical depletion between stars with C-rich and O-rich circumbinary disc chemistries. However, critical observational studies of circumbinary disc chemistry, along with specific condensation temperature estimates in C-rich environments, are necessary to address gaps in our current understanding of disc-binary interactions inducing chemical depletion in binary post-AGB systems.
“…10) further confirms the absence of a photospheric chemical depletion. Therefore, we dismiss the possibility of an s -process enrichment following a chemical depletion. Figure 11. Wise colour-colour diagram for the target stars along with the stars studied in Kluska et al (2022). The dashed black lines represent the boundaries between the different categories defined in Kluska et al (2022).…”
Section: Discussionmentioning
confidence: 99%
“…Therefore, we dismiss the possibility of an s -process enrichment following a chemical depletion. Figure 11. Wise colour-colour diagram for the target stars along with the stars studied in Kluska et al (2022). The dashed black lines represent the boundaries between the different categories defined in Kluska et al (2022). The targets of this study are given in magenta colour and are numbered according to their position in Table 1 for reference.…”
Section: Discussionmentioning
confidence: 99%
“…Wise colour-colour diagram for the target stars along with the stars studied in Kluska et al (2022). The dashed black lines represent the boundaries between the different categories defined in Kluska et al (2022).…”
Section: Discussionmentioning
confidence: 99%
“…We adopted the same approach described in Kluska et al (2022) and Kamath et al (2022) to construct all the SEDs in this study. In summary, we began by determining the total line-of-sight reddening or extinction parameter () by minimising the difference between the optical fluxes and the reddened photospheric models.…”
Section: Photometric Analysismentioning
confidence: 99%
“…Observational studies have now firmly established that the presence of the stable compact disc (circumbinary disc) around the disc-sources is attributed to their binary nature (e.g. Van Winckel et al 2009; Oomen et al 2018; Kluska et al 2022).…”
Post-asymptotic giant branch stars (post-AGB) in binary systems, with typical orbital periods between ∼100 to ∼1000 days, result from a poorly understood interaction that terminates their precursory AGB phase. The majority of these binaries display a photospheric anomaly called ‘chemical depletion’, thought to arise froman interaction between the circumbinary disc and the post-AGB star, leading to the reaccretion of pure gas onto the star, devoid of refractory elements due to dust formation. In this paper, we focus on a subset of chemically peculiar binary post-AGBs in the Galaxy and the Magellanic Clouds (MCs). Our detailed stellar parameter and chemical abundance analysis utilising high-resolution optical spectra from VLT+UVES revealed that our targets span a Teff of 4900 - 7250K and [Fe/H] of -0.5 - -1.57 dex. Interestingly, these targets exhibit a carbon ([C/Fe] ranging from 0.5 - 1.0 dex, dependant on metallicity) and s-process enrichment ([s/Fe]≥1dex) contrary to the commonly observed chemical depletion pattern. Using spectral energy distribution (SED) fitting and period-luminosity-colour (PLC) relation methods, we determine the luminosity of the targets (2700 – 8300 L⊙), which enables confirmation of their evolutionary phase and estimation of initial masses (as a function of metallicity) (1 - 2.5M⊙). In conjunction with predictions from dedicated ATON stellar evolutionary models, our results indicate a predominant intrinsic enrichment of carbon and s-process elements in our binary post-AGB targets. We qualitatively rule out extrinsic enrichment and inherited s-process enrichment from the host galaxy as plausible explanations for the observed overabundances. Our chemically peculiar subset of intrinsic carbon and s-process enriched binary post-AGBs also hints at potential variation in the efficiency of chemical depletion between stars with C-rich and O-rich circumbinary disc chemistries. However, critical observational studies of circumbinary disc chemistry, along with specific condensation temperature estimates in C-rich environments, are necessary to address gaps in our current understanding of disc-binary interactions inducing chemical depletion in binary post-AGB systems.
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