19 results on '"Hawcroft, Calum"'
Search Results
2. Spectroscopic characterisation of gravitationally lensed stars at high redshifts
- Author
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Lundqvist, Emma, Zackrisson, Erik, Hawcroft, Calum, Amarsi, Anish M., and Welch, Brian
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
Deep imaging of galaxy cluster fields have in recent years revealed tens of candidates for gravitationally lensed stars at redshifts $z\approx$ 1-6, and future searches are expected to reveal highly magnified stars from even earlier epochs. Multi-band photometric observations may be used to constrain the redshift, effective temperature $T_\mathrm{eff}$ and dust attenuation along the line of sight to such objects. When combined with an estimate of the likely magnification, these quantities may be converted into a constraint on the stellar luminosity and, for an adopted set of stellar evolutionary tracks, the initial stellar mass. Further characterization is, however, difficult without spectroscopic observations, which at the typical brightness levels of high-redshift lensed stars becomes extremely challenging for even the largest existing telescopes. Here, we explore what spectral features one can realistically hope to detect in lensed stars with peak brightness in the range 26-28 AB mag, $T_\mathrm{eff}=$ 4000-50 000 K and redshifts $z=$1-10, using spectroscopy with the James Webb Space Telescope (JWST) and the forthcoming Extremely Large Telescope. We find that a majority of detectable lines appear in the rest UV-range for stars with $T_\mathrm{eff}\geq$15 000 K. The strongest detectable spectral lines are the C IV $\lambda$ 1550 \r{A} line and the Si IV $\lambda\lambda$1393, 1403 \r{A}-doublet at $T_\mathrm{eff}=$30 000 K. For lower temperatures, the calcium H- and K-lines at $T_\mathrm{eff}=$6000 K are among the most readily detectable. In limited wavelength ranges, ELT is expected to provide more sensitive spectroscopic observations, and with higher resolution than JWST. We find that variations of both mass loss rate and metallicity lead to noticeable effects in the detectability of certain spectral lines with both JWST and ELT., Comment: 12 pages, 6 figures, accepted in A&A
- Published
- 2024
- Full Text
- View/download PDF
3. The Nature of Unseen Companions in Massive Single-Line Spectroscopic Binaries
- Author
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Sana, Hugues, Abdul-Masih, Michael, Banyard, Gareth, Bodensteiner, Julia, Bowman, Dominic M., Dsilva, Karan, Eldridge, C., Fabry, Matthias, Frost, Abigail J., Hawcroft, Calum, Janssens, Soetkin, Mahy, Laurent, Marchant, Pablo, Langer, Norbert, Van Reeth, Timothy, Sen, Koushik, and Shenar, Tomer
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Massive stars are predominantly found in binaries and higher order multiples. While the period and eccentricity distributions of OB stars are now well established across different metallicity regimes, the determination of mass-ratios has been mostly limited to double-lined spectroscopic binaries. As a consequence, the mass-ratio distribution remains subject to significant uncertainties. Open questions include the shape and extent of the companion mass-function towards its low-mass end and the nature of undetected companions in single-lined spectroscopic binaries. In this contribution, we present the results of a large and systematic analysis of a sample of over 80 single-lined O-type spectroscopic binaries (SB1s) in the Milky Way and in the Large Magellanic Cloud (LMC). We report on the developed methodology, the constraints obtained on the nature of SB1 companions, the distribution of O star mass-ratios at LMC metallicity and the occurrence of quiescent OB+black hole binaries., Comment: To appear in the proceedings of IAUS361: Massive stars near and far; 6 pages, 1 figure
- Published
- 2022
4. An X-ray quiet black hole born with a negligible kick in a massive binary within the Large Magellanic Cloud
- Author
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Shenar, Tomer, Sana, Hugues, Mahy, Laurent, El-Badry, Kareem, Marchant, Pablo, Langer, Norbert, Hawcroft, Calum, Fabry, Matthias, Sen, Koushik, Almeida, Leonardo A., Abdul-Masih, Michael, Bodensteiner, Julia, Crowther, Paul A., Gieles, Mark, Gromadzki, Mariusz, Henault-Brunet, Vincent, Herrero, Artemio, de Koter, Alex, Iwanek, Patryk, Kozłowski, Szymon, Lennon, Daniel J., Apellaniz, Jesus Maız, Mroz, Przemysław, Moffat, Anthony F. J., Picco, Annachiara, Pietrukowicz, Paweł, Poleski, Radosław, Rybicki, Krzysztof, Schneider, Fabian R. N., Skowron, Dorota M., Skowron, Jan, Soszynski, Igor, Szymanski, Michał K., Toonen, Silvia, Udalski, Andrzej, Ulaczyk, Krzysztof, Vink, Jorick S., and Wrona, Marcin
- Subjects
Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Stellar-mass black holes are the final remnants of stars born with more than 15 solar masses. Billions are expected to reside in the Local Group, yet only few are known, mostly detected through X-rays emitted as they accrete material from a companion star. Here, we report on VFTS 243: a massive X-ray faint binary in the Large Magellanic Cloud. With an orbital period of 10.4-d, it comprises an O-type star of 25 solar masses and an unseen companion of at least nine solar masses. Our spectral analysis excludes a non-degenerate companion at a 5-sigma confidence level. The minimum companion mass implies that it is a black hole. No other X-ray quiet black hole is unambiguously known outside our Galaxy. The (near-)circular orbit and kinematics of VFTS 243 imply that the collapse of the progenitor into a black hole was associated with little or no ejected material or black-hole kick. Identifying such unique binaries substantially impacts the predicted rates of gravitational-wave detections and properties of core-collapse supernovae across the Cosmos., Comment: Accepted to Nature Astronomy, 64 pages, 15 figures, 2 tables; ESO press release: https://www.eso.org/public/news/eso2210/; Nat Asr paper URL: https://www.nature.com/articles/s41550-022-01730-y
- Published
- 2022
- Full Text
- View/download PDF
5. The R136 star cluster dissected with Hubble Space Telescope/STIS. III. The most massive stars and their clumped winds
- Author
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Brands, Sarah A., de Koter, Alex, Bestenlehner, Joachim M., Crowther, Paul A., Sundqvist, Jon O., Puls, Joachim, Caballero-Nieves, Saida M., Abdul-Masih, Michael, Driessen, Florian A., García, Miriam, Geen, Sam, Gräfener, Götz, Hawcroft, Calum, Kaper, Lex, Keszthelyi, Zsolt, Langer, Norbert, Sana, Hugues, Schneider, Fabian R. N., Shenar, Tomer, and Vink, Jorick S.
- Subjects
Astrophysics - Solar and Stellar Astrophysics - Abstract
Context: The star cluster R136 inside the LMC hosts a rich population of massive stars, including the most massive stars known. The strong stellar winds of these very luminous stars impact their evolution and the surrounding environment. We currently lack detailed knowledge of the wind structure that is needed to quantify this impact. Aims: To observationally constrain the stellar and wind properties of the massive stars in R136, in particular the parameters related to wind clumping. Methods: We simultaneously analyse optical and UV spectroscopy of 53 O-type and 3 WNh-stars using the FASTWIND model atmosphere code and a genetic algorithm. The models account for optically thick clumps and effects related to porosity and velocity-porosity, as well as a non-void interclump medium. Results: We obtain stellar parameters, surface abundances, mass-loss rates, terminal velocities and clumping characteristics and compare these to theoretical predictions and evolutionary models. The clumping properties include the density of the interclump medium and the velocity-porosity of the wind. For the first time, these characteristics are systematically measured for a wide range of effective temperatures and luminosities. Conclusions: We confirm a cluster age of 1.0-2.5 Myr and derive an initial stellar mass of $\geq 250 {\rm M}_\odot$ for the most massive star in our sample, R136a1. The winds of our sample stars are highly clumped, with an average clumping factor of $f_{\rm cl}=29\pm15$. We find tentative trends in the wind-structure parameters as a function of mass-loss rate, suggesting that the winds of stars with higher mass-loss rates are less clumped. We compare several theoretical predictions to the observed mass-loss rates and terminal velocities and find that none satisfactorily reproduces both quantities. The prescription of Krti\v{c}ka & Kub\'at (2018) matches best the observed mass-loss rates., Comment: Accepted for publication in A&A; Appendix I will not be included in the published version
- Published
- 2022
- Full Text
- View/download PDF
6. Constraining the Overcontact Phase in Massive Binary Evolution I. Mixing in V382 Cyg, VFTS 352, and OGLE SMC-SC10 108086
- Author
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Abdul-Masih, Michael, Sana, Hugues, Hawcroft, Calum, Almeida, Leonardo A., Brands, Sarah A., de Mink, Selma E., Justham, Stephen, Langer, Norbert, Mahy, Laurent, Marchant, Pablo, Menon, Athira, Puls, Joachim, and Sundqvist, Jon
- Subjects
Astrophysics - Solar and Stellar Astrophysics - Abstract
As potential progenitors of several exotic phenomena including gravitational wave sources, magnetic stars, and Be stars, close massive binary systems probe a crucial area of the parameter space in massive star evolution. Despite the importance of these systems, large uncertainties regarding the nature and efficiency of the internal mixing mechanisms still exist. In this work, we aim to provide robust observational constraints on the internal mixing processes by spectroscopically analyzing a sample of three massive overcontact binaries at different metallicities. Using optical phase-resolved spectroscopic data, we perform an atmosphere analysis using more traditional 1D techniques and using state-of-the-art 3D techniques. We compare and contrast the assumptions and results of each technique and investigate how the assumptions affect the final derived atmospheric parameters. We find that in all three cases, both components of system are highly overluminous indicating either efficient internal mixing of helium or previous non-conservative mass transfer. However, we do not find strong evidence of helium or CNO surface abundance changes usually associated with mixing. Additionally, we find that in unequal mass systems, the measured effective temperature and luminosity of the less massive component places it very close to the more massive component on the Hertzsprung-Russell diagram. These results were obtained independently using both of the techniques mentioned above, which suggests that these measurements are robust. The observed discrepancies between the temperature and the surface abundance measurements when compared to theoretical expectations indicate that unaccounted for additional physical mechanisms may be at play., Comment: Accepted for publication in A&A; 28 pages, 20 figures
- Published
- 2021
- Full Text
- View/download PDF
7. Characterization of the variability in the O+B eclipsing binary HD 165246
- Author
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Johnston, Cole, Aimar, Nicolas, Abdul-Masih, Michael, Bowman, Dominic. M., White, Tim R., Hawcroft, Calum, Sana, Hugues, Sekaran, Sanjay, Dsilva, Karan, Tkachenko, Andrew, and Aerts, Conny
- Subjects
Astrophysics - Solar and Stellar Astrophysics - Abstract
O-stars are known to experience a wide range of variability mechanisms originating at both their surface and their near-core regions. Characterization and understanding of this variability and its potential causes are integral for evolutionary calculations. We use a new extensive high-resolution spectroscopic data set to characterize the variability observed in both the spectroscopic and space-based photometric observations of the O+B eclipsing binary HD~165246. We present an updated atmospheric and binary solution for the primary component, involving a high level of microturbulence ($13_{-1.3}^{+1.0}\,$km\,s$^{-1}$) and a mass of $M_1=23.7_{-1.4}^{+1.1}$~M$_{\odot}$, placing it in a sparsely explored region of the Hertzsprung-Russell diagram. Furthermore, we deduce a rotational frequency of $0.690\pm 0.003\,$d$^{-1}$ from the combined photometric and line-profile variability, implying that the primary rotates at 40\% of its critical Keplerian rotation rate. We discuss the potential explanations for the overall variability observed in this massive binary, and discuss its evolutionary context., Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society, 14 pages, 10 figures, 6 tables, 1 appendix (4 additional figures)
- Published
- 2021
- Full Text
- View/download PDF
8. No signature of the orbital motion of a putative 70 solar mass black hole in LB-1
- Author
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Abdul-Masih, Michael, Banyard, Gareth, Bodensteiner, Julia, Bowman, Dominic M., Dsilva, Karan, Fabry, Matthias, Hawcroft, Calum, Mahy, Laurent, Marchant, Pablo, Raskin, Gert, Reggiani, Maddalena, Sana, Hugues, Shenar, Tomer, Tkachenko, Andrew, Van Winckel, Hans, and Vermeylen, Lore
- Subjects
Astrophysics - Solar and Stellar Astrophysics - Abstract
Liu et al. (2019) recently reported the detection of a 68 [+11/-13] solar mass (Msun) black hole (BH) paired with an 8.2 [+0.9/-1.2] Msun B-type sub-giant star in the 78.9-day spectroscopic binary system LB-1. Such a black hole is over twice as massive as any other known stellar-mass black hole with non-compact companions2 and its mass approaches those that result from BH-BH coalescences that are detected by gravitational wave interferometers. Its presence in a solar-like metallicity environment challenges conventional theories of massive binary evolution, stellar winds and core-collapse supernovae, so that more exotic scenarios seem to be needed to explain the existence and properties of LB-1. Here, we show that the observational diagnostics used to derive the BH mass results from the orbital motion of the B-type star, not that of the BH. As a consequence, no evidence for a massive BH remains in the data, therefore solving the existing tension with formation models of such a massive BH at solar metallicity and with theories of massive star evolution in general., Comment: 10 pages, 8 figures
- Published
- 2019
- Full Text
- View/download PDF
9. On the signature of a 70-solar-mass black hole in LB-1
- Author
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Abdul-Masih, Michael, Banyard, Gareth, Bodensteiner, Julia, Bordier, Emma, Bowman, Dominic M., Dsilva, Karan, Fabry, Matthias, Hawcroft, Calum, Mahy, Laurent, Marchant, Pablo, Raskin, Gert, Reggiani, Maddalena, Shenar, Tomer, Tkachenko, Andrew, Van Winckel, Hans, Vermeylen, Lore, and Sana, Hugues
- Published
- 2020
- Full Text
- View/download PDF
10. The Nature of Unseen Companions in Massive Single-Line Spectroscopic Binaries.
- Author
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Sana, Hugues, Abdul-Masih, Michael, Banyard, Gareth, Bodensteiner, Julia, Bowman, Dominic M., Dsilva, Karan, Eldridge, C., Fabry, Matthias, Frost, Abigail J., Hawcroft, Calum, Janssens, Soetkin, Mahy, Laurent, Marchant, Pablo, Langer, Norbert, Van Reeth, Timothy, Sen, Koushik, and Shenar, Tomer
- Subjects
STELLAR evolution ,LARGE magellanic cloud ,SUPERGIANT stars ,BINARY black holes ,GRAVITATIONAL waves - Abstract
Massive stars are predominantly found in binaries and higher order multiples. While the period and eccentricity distributions of OB stars are now well established across different metallicity regimes, the determination of mass-ratios has been mostly limited to double-lined spectroscopic binaries. As a consequence, the mass-ratio distribution remains subject to significant uncertainties. Open questions include the shape and extent of the companion mass-function towards its low-mass end and the nature of undetected companions in single-lined spectroscopic binaries. In this contribution, we present the results of a large and systematic analysis of a sample of over 80 single-lined O-type spectroscopic binaries (SB1s) in the Milky Way and in the Large Magellanic Cloud (LMC). We report on the developed methodology, the constraints obtained on the nature of SB1 companions, the distribution of O star mass-ratios at LMC metallicity and the occurrence of quiescent OB+black hole binaries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. The clumped winds of the most massive stars.
- Author
-
Brands, Sarah A., de Koter, Alex, Bestenlehner, Joachim M., Crowther, Paul A., Sundqvist, Jon O., Puls, Joachim, Caballero-Nieves, Saida M., Abdul-Masih, Michael, Driessen, Florian A., García, Miriam, Geen, Sam, Gräfener, Götz, Hawcroft, Calum, Kaper, Lex, Keszthelyi, Zsolt, Langer, Norbert, Sana, Hugues, Schneider, Fabian R. N., Shenar, Tomer, and Vink, Jorick S.
- Subjects
STELLAR atmospheres ,LARGE magellanic cloud ,SUPERGIANT stars ,STELLAR evolution ,STELLAR mass ,MASS loss (Astrophysics) ,STELLAR winds - Abstract
The core of the cluster R136 in the Large Magellanic Cloud hosts the most massive stars known. The high mass-loss rates of these stars strongly impact their surroundings, as well as the evolution of the stars themselves. To quantify this impact accurate mass-loss rates are needed, however, uncertainty about the degree of inhomogeneity of the winds ('wind clumping'), makes mass-loss measurements uncertain. We combine optical and ultraviolet HST/STIS spectroscopy of 56 stars in the core of R136 in order to put constraints on the wind structure, improving the accuracy of the mass-loss rate measurements. We find that the winds are highly clumped, and use our measured mass-loss rates to test theoretical predictions. Furthermore we find, for the first time, tentative trends in the wind-structure parameters as a function of mass-loss rate, suggesting that the winds of stars with higher mass-loss rates are less clumped than those with lower mass-loss rates. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. HR 6819 – a post-interaction binary system originally thought to be a triple system containing a black hole.
- Author
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Frost, Abigail J., Bodensteiner, Julia, Rivinius, Thomas, Baade, Dietrich, Merand, Antoine, Selman, Fernando, Abdul-Masih, Michael, Banyard, Gareth, Bordier, Emma, Dsilva, Karan, Hawcroft, Calum, Mahy, Laurent, Reggiani, Maddalena, Shenar, Tomer, Cabezas, Mauricio, Hadrava, Petr, Heida, Marianne, Klement, Robert, and Sana, Hugues
- Subjects
BLACK holes ,BINARY stars ,CHERNOZEM soils ,SYSTEMS theory ,INTEGRALS - Abstract
In 2020, HR 6819 was reported to be a triple system containing the closest black hole to Earth. However, these results were contested, with an alternative explanation of a post-interaction binary suggested. Using new integral field spectroscopic and interferometric data, we have been able to determine the true nature of this exotic source. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. An X-ray-quiet black hole born with a negligible kick in a massive binary within the Large Magellanic Cloud
- Author
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Shenar, Tomer, primary, Sana, Hugues, additional, Mahy, Laurent, additional, El-Badry, Kareem, additional, Marchant, Pablo, additional, Langer, Norbert, additional, Hawcroft, Calum, additional, Fabry, Matthias, additional, Sen, Koushik, additional, Almeida, Leonardo A., additional, Abdul-Masih, Michael, additional, Bodensteiner, Julia, additional, Crowther, Paul A., additional, Gieles, Mark, additional, Gromadzki, Mariusz, additional, Hénault-Brunet, Vincent, additional, Herrero, Artemio, additional, Koter, Alex de, additional, Iwanek, Patryk, additional, Kozłowski, Szymon, additional, Lennon, Daniel J., additional, Apellániz, Jesús Maíz, additional, Mróz, Przemysław, additional, Moffat, Anthony F. J., additional, Picco, Annachiara, additional, Pietrukowicz, Paweł, additional, Poleski, Radosław, additional, Rybicki, Krzysztof, additional, Schneider, Fabian R. N., additional, Skowron, Dorota M., additional, Skowron, Jan, additional, Soszyński, Igor, additional, Szymański, Michał K., additional, Toonen, Silvia, additional, Udalski, Andrzej, additional, Ulaczyk, Krzysztof, additional, Vink, Jorick S., additional, and Wrona, Marcin, additional
- Published
- 2022
- Full Text
- View/download PDF
14. The R136 star cluster dissected with Hubble Space Telescope/STIS
- Author
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Brands, Sarah A., primary, de Koter, Alex, additional, Bestenlehner, Joachim M., additional, Crowther, Paul A., additional, Sundqvist, Jon O., additional, Puls, Joachim, additional, Caballero-Nieves, Saida M., additional, Abdul-Masih, Michael, additional, Driessen, Florian A., additional, García, Miriam, additional, Geen, Sam, additional, Gräfener, Götz, additional, Hawcroft, Calum, additional, Kaper, Lex, additional, Keszthelyi, Zsolt, additional, Langer, Norbert, additional, Sana, Hugues, additional, Schneider, Fabian R. N., additional, Shenar, Tomer, additional, and Vink, Jorick S., additional
- Published
- 2022
- Full Text
- View/download PDF
15. Constraining the dynamical mass of the massive binary 9 Sagittarii.
- Author
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Fabry, Matthias, Hawcroft, Calum, Frost, Abigail J., Mahy, Laurent, Marchant, Pablo, Le Bouquin, Jean-Baptiste, and Sana, Hugues
- Subjects
- *
BINARY stars , *HR diagrams - Abstract
Especially in the upper Hertzsprung-Russell diagram, where stellar physics is least understood, obtaining model independent masses is of great value. Spectroscopic binaries that are also resolved astrometrically are an excellent alternative to eclipsing double-lined spectroscopic binaries where dynamical masses can be measured. 9 Sgr is such a massive binary. However, its characterization is troubled by conflicting conclusions from the spectroscopic analysis on the one hand and the interferometric one on the other hand. In this work, we attempt to resolve this tension by applying a novel approach to spectral disentangling of the spectroscopic data to constrain better the mass of 9 Sgr. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. The clumped winds of the most massive stars.
- Author
-
Brands, Sarah A., de Koter, Alex, Bestenlehner, Joachim M., Crowther, Paul A., Sundqvist, Jon O., Puls, Joachim, Caballero-Nieves, Saida M., Abdul-Masih, Michael, Driessen, Florian A., García, Miriam, Geen, Sam, Gräfener, Götz, Hawcroft, Calum, Kaper, Lex, Keszthelyi, Zsolt, Langer, Norbert, Sana, Hugues, Schneider, Fabian R. N., Shenar, Tomer, and Vink, Jorick S.
- Subjects
STELLAR atmospheres ,LARGE magellanic cloud ,SUPERGIANT stars ,STELLAR evolution ,STELLAR mass ,MASS loss (Astrophysics) ,STELLAR winds - Abstract
The core of the cluster R136 in the Large Magellanic Cloud hosts the most massive stars known. The high mass-loss rates of these stars strongly impact their surroundings, as well as the evolution of the stars themselves. To quantify this impact accurate mass-loss rates are needed, however, uncertainty about the degree of inhomogeneity of the winds ('wind clumping'), makes mass-loss measurements uncertain. We combine optical and ultraviolet HST/STIS spectroscopy of 56 stars in the core of R136 in order to put constraints on the wind structure, improving the accuracy of the mass-loss rate measurements. We find that the winds are highly clumped, and use our measured mass-loss rates to test theoretical predictions. Furthermore we find, for the first time, tentative trends in the wind-structure parameters as a function of mass-loss rate, suggesting that the winds of stars with higher mass-loss rates are less clumped than those with lower mass-loss rates. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
17. HR 6819 – a post-interaction binary system originally thought to be a triple system containing a black hole.
- Author
-
Frost, Abigail J., Bodensteiner, Julia, Rivinius, Thomas, Baade, Dietrich, Merand, Antoine, Selman, Fernando, Abdul-Masih, Michael, Banyard, Gareth, Bordier, Emma, Dsilva, Karan, Hawcroft, Calum, Mahy, Laurent, Reggiani, Maddalena, Shenar, Tomer, Cabezas, Mauricio, Hadrava, Petr, Heida, Marianne, Klement, Robert, and Sana, Hugues
- Subjects
BLACK holes ,BINARY stars ,CHERNOZEM soils ,SYSTEMS theory ,INTEGRALS - Abstract
In 2020, HR 6819 was reported to be a triple system containing the closest black hole to Earth. However, these results were contested, with an alternative explanation of a post-interaction binary suggested. Using new integral field spectroscopic and interferometric data, we have been able to determine the true nature of this exotic source. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Constraining the dynamical mass of the massive binary 9 Sagittarii.
- Author
-
Fabry, Matthias, Hawcroft, Calum, Frost, Abigail J., Mahy, Laurent, Marchant, Pablo, Le Bouquin, Jean-Baptiste, and Sana, Hugues
- Subjects
- *
BINARY stars , *HR diagrams - Abstract
Especially in the upper Hertzsprung-Russell diagram, where stellar physics is least understood, obtaining model independent masses is of great value. Spectroscopic binaries that are also resolved astrometrically are an excellent alternative to eclipsing double-lined spectroscopic binaries where dynamical masses can be measured. 9 Sgr is such a massive binary. However, its characterization is troubled by conflicting conclusions from the spectroscopic analysis on the one hand and the interferometric one on the other hand. In this work, we attempt to resolve this tension by applying a novel approach to spectral disentangling of the spectroscopic data to constrain better the mass of 9 Sgr. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
19. Constraining the overcontact phase in massive binary evolution
- Author
-
Abdul-Masih, Michael, Sana, Hugues, Hawcroft, Calum, Almeida, Leonardo A., Brands, Sarah A., de Mink, Selma E., Justham, Stephen, Langer, Norbert, Mahy, Laurent, Marchant, Pablo, Menon, Athira, Puls, Joachim, and Sundqvist, Jon
- Full Text
- View/download PDF
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