Article
Astronomy & Astrophysics
Na Wei, Long Jiang, Wen-Cong Chen
Summary: The study found that Source 2A 1822-371 is a low-mass X-ray binary system with a rapidly expanding orbital period and an anomalously high mass-transfer rate. The researchers proposed a CB disk model to explain this phenomenon and conducted simulations to validate their hypothesis.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Surjit S. Wadhwa, Natalia R. Landin, Petar Kostic, Oliver Vince, Bojan Arbutina, Ain Y. De Horta, Miroslav D. Filipovic, Nicholas F. H. Tothill, Jelena Petrovic, Gojko Djurasevic
Summary: The orbital stability of contact binary systems has attracted attention recently. Theoretical studies suggest that merger is likely to occur at very low mass ratios, but the actual mass ratio for merger may vary and depend on the mass of the primary star. In this study, we investigate the effects of metal content on the orbital stability of contact binary systems by examining the gyration radius of the rotating and tidally distorted primary star at different metallicities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Arnab Sarkar, Christopher A. Tout
Summary: We present an updated version of a stellar evolution code that can model the evolution of cool white dwarfs and cataclysmic variable stars. The code includes a double dynamo model that explains the interrupted magnetic braking paradigm and provides a mechanism for angular momentum loss below the period gap. Our model accurately reproduces the observed period gap and period minimum spike in the distribution of cataclysmic variable stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Arnab Sarkar, Hongwei Ge, Christopher A. Tout
Summary: We model cataclysmic variables (CVs) with solar metallicity donors and find that the time-scale for angular momentum loss by magnetic braking in our model is shorter than previous empirical formulae. The Double Dynamo model allows for a larger parameter space to form AM CVn stars. Our analysis shows that the number of AM CVn stars formed through the evolved CV channel is about three times greater than previously reported. The Cambridge stellar evolution code is used to evolve these systems and it is found that evolved CVs can have orbital periods of 5.5 hours or longer. Comparison with observations shows that our model matches the properties of systems such as YZ LMi and V396 Hya, and may also match systems like CR Boo and HP Lib if their actual donor mass is at the lower end of the observed mass range.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
G. Lenoir-Craig, I. I. Antokhin, E. A. Antokhina, N. St-Louis, A. F. J. Moffat
Summary: WR22 = HD 92740 is a bright double-line WN7h + O9III-V binary system, exhibiting a deep eclipse phenomenon during periastron passage. Models L96 and A13 are applied to analyze the optical observations, providing insights into the physical characteristics of the stars in the binary system.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
L. Perot, N. Chamel
Summary: Space-based gravitational-wave detectors provide new possibilities for studying the crystallization of white dwarfs in binary systems by analyzing the tidal effects on the gravitational-wave signals. The elasticity of the crystallized core is found to reduce the tidal deformability, especially for low-mass stars. The relativistic correction to the observable tidal deformability becomes increasingly important for more massive white dwarfs.
Article
Astronomy & Astrophysics
G. Lenoir-Craig, N. St-Louis, A. F. J. Moffat, H. Pablo
Summary: This study describes the challenges in observing the variable photometric properties of the binary system WR48 in the Theta Mus = HD 113904 system due to the interference from the highly luminous blue supergiant BSG. Despite extensive optical space-based photometry, the intrinsic stochastic variability from the BSG continues to hinder the detection of atmospheric eclipse in the system. By adopting a more reliable orbital inclination, researchers were able to obtain an upper limit for the mass-loss rate of the WR component and the depth of the atmospheric eclipse in the WR48 subsystem.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
E. Han, S. A. Rappaport, A. Vanderburg, B. M. Tofflemire, T. Borkovits, H. M. Schwengeler, P. Zasche, D. M. Krolikowski, P. S. Muirhead, M. H. Kristiansen, I. A. Terentev, M. Omohundro, R. Gagliano, T. Jacobs, D. LaCourse
Summary: The analysis presents a newly discovered quadruple star system with an unresolved eclipsing binary and a close neighbor. By utilizing light centroid analysis and radial velocity data, the stellar masses and orbital characteristics of the system were determined.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
K. D. Temmink, O. R. Pols, S. Justham, A. G. Istrate, S. Toonen
Summary: This study systematically investigates the behavior of mass-losing donor stars in binary systems, with a focus on identifying and understanding the parameter space for stable mass transfer. The results indicate that mass transfer is stable for a wider range of binary parameter space than typically assumed in rapid binary population synthesis.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Albert Bruch
Summary: Superhumps are variable phenomena observed in cataclysmic variables, coming in positive and negative flavors. Positive superhumps are common in short-period dwarf novae while negative superhumps are not preference for a particular type. This study utilizes TESS's long high-cadence light curves to analyze superhump behavior in old novae and novalike variables, resulting in the most comprehensive census of superhumps in these stars. Furthermore, eclipse epochs derived from the TESS light curves are used to update orbital ephemeris and discuss period changes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Z. Jennings, J. Southworth, P. F. L. Maxted, L. Mancini
Summary: Precise measurements of stellar parameters are essential for understanding stellar structure. In this study, TESS light curves and radial velocity measurements were used to study low mass eclipsing binaries. The results provide new measurements and insights into the fundamental properties and effective temperatures of M dwarfs, and highlight the need to develop our understanding of the complex physical processes governing the evolution of low-mass stars. The hypothesis regarding the unaffected luminosity by the inflation problem is inconclusive.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Surjit S. Wadhwa, Ain De Horta, Miroslav D. Filipovic, N. F. H. Tothill, Bojan Arbutina, Jelena Petrovic, Gojko Djurasevic
Summary: ZZ Piscis Austrinus is a neglected bright southern contact binary system with a low mass ratio, potentially being a merger candidate.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Wenbin Lu, Jim Fuller, Eliot Quataert, Clement Bonnerot
Summary: In some semidetached binary systems, a large fraction of the transferred mass may be lost through the outer Lagrangian point due to excessive energy generated by viscous heating. A physical model is constructed to explain the process and predict significant mass loss at high mass-transfer rates. The implications for the system's orbital evolution and observational appearance are discussed.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Surjit S. Wadhwa, Jelena Petrovic, Nick F. H. Tothill, Ain Y. De Horta, Miroslav D. Filipovic, Gojko Djurasevic
Summary: This study presents photometric and spectroscopic observations of two recently identified contact binary systems. The analysis shows that both systems have very low mass ratios, indicating they are unlikely to merge and likely to be in a stable orbit. Additionally, the secondary stars in both systems are larger and more luminous than their main sequence counterparts, with a considerably higher density.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Albert Bruch
Summary: This study identifies and characterizes periodic and non-periodic variations in high cadence light curves of cataclysmic variables. The results are presented for 23 nova-like variables and old novae out of a sample of 127 systems. The study explores the basic properties of superhumps and updates previous data on superhumps and the Stolz-Schoembs relation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
C. Galan, J. Mikolajewska, K. Ilkiewicz, B. Monard, S. T. Zywica, R. K. Zamanov
Summary: This paper analyzes the nature and evolution of a relatively poorly studied S-type symbiotic system, St 2-22. Through 16 years of photometric monitoring and high-quality spectroscopic data, the orbital and stellar parameters of the system components are derived, and the evolution of the jet is studied.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
L. Molnar, A. Bodi, A. Pal, A. Bhardwaj, F-J Hambsch, J. M. Benko, A. Derekas, M. Ebadi, M. Joyce, A. Hasanzadeh, K. Kolenberg, M. B. Lund, J. M. Nemec, H. Netzel, C. -C Ngeow, J. Pepper, E. Plachy, Z. Prudil, R. J. Siverd, M. Skarka, R. Smolec, A. Sodor, S. Sylla, P. Szabo, R. Szabo, H. Kjeldsen, J. Christensen-Dalsgaard, G. R. Ricker
Summary: The TESS space telescope is studying RR Lyrae stars and found that their mode distribution is different from that of bulge stars, potentially due to differences in physical parameters. However, uncertainties in determining the true pulsation frequencies of the extra modes hinder mode identification. In addition, a high percentage of modulated stars are found among fundamental mode pulsators, but a significant fraction of stars lack the Blazhko effect.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2022)
Article
Astronomy & Astrophysics
Erika M. Holmbeck, Richard O'Shaughnessy, Vera Delfavero, Krzysztof Belczynski
Summary: By modeling the outflows of NSMs and comparing them to the abundances observed in metal-poor stars, researchers have derived a hypothetical equation of state (EOS) that is consistent with current constraints.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Paulina Karczmarek, Radoslaw Smolec, Gergely Hajdu, Grzegorz Pietrzynski, Wolfgang Gieren, Weronika Narloch, Grzegorz Wiktorowicz, Krzysztof Belczynski
Summary: This study presents an extensive investigation of synthetic populations of binary Cepheids, aiming to characterize the companions of Cepheids, quantify their contribution to the brightness and color of Cepheid binaries, and assess the significance of input parameters on the results. The research successfully reproduces recent theoretical and empirical findings and provides new estimates on the percentage of binary Cepheids in the Large Magellanic Cloud. It also quantifies the effect of binarity on the slope and zero-point of multiband period-luminosity relations.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Chris L. Fryer, Aleksandra Olejak, Krzysztof Belczynski
Summary: This paper reviews the understanding of convection in stellar collapse and its effect on the remnant mass distribution. The study finds that both convection growth and rotation have an impact on the distribution of remnant masses.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Piotr Wielgorski, Grzegorz Pietrzynski, Bogumil Pilecki, Wolfgang Gieren, Bartlomiej Zgirski, Marek Gorski, Gergely Hajdu, Weronika Narloch, Paulina Karczmarek, Radoslaw Smolec, Pierre Kervella, Jesper Storm, Alexandre Gallenne, Louise Breuval, Megan Lewis, Mikolaj Kaluszynski, Dariusz Graczyk, Wojciech Pych, Ksenia Suchomska, Monica Taormina, Gonzalo Rojas Garcia, Aleksandra Kotek, Rolf Chini, Francisco Pozo Nunez, Sadegh Noroozi, Catalina Sobrino Figaredo, Martin Haas, Klaus Hodapp, Przemyslaw Mikolajczyk, Krzysztof Kotysz, Dawid Mozdzierski, Piotr Kolaczek-Szymanski
Summary: This study presents the period-luminosity relations (PLRs) of type II Cepheids in the near-infrared regime, using time-series photometry and Gaia parallaxes. The study finds that BL Herculis stars have narrow PLRs, making them potential precision distance indicators. By recalibrating PLRs using archival photometry, accurate distances, and metallicity effects, the study determines the distance modulus of the Large Magellanic Cloud and its metallicity effect.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Debatri Chattopadhyay, Simon Stevenson, Floor Broekgaarden, Fabio Antonini, Krzysztof Belczynski
Summary: The isolated binary evolution of two neutron star-black hole systems is studied using a grid of population synthesis models. The results suggest that these systems may originate from stars with lower metallicity. Chirp mass and remnant spins are found to be useful in constraining the models, while the effective spin parameter does not provide additional information. Distinguishable features in the distribution of remnant spin parameters are observed in different sub-populations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
W. Narloch, G. Pietrzynski, W. Gieren, A. E. Piatti, P. Karczmarek, M. Gorski, D. Graczyk, R. Smolec, G. Hajdu, K. Suchomska, B. Zgirski, P. Wielgorski, B. Pilecki, M. Taormina, M. Kaluszynski, W. Pych, G. Rojas Garcia, M. O. Lewis
Summary: This study investigates 147 star clusters in the Large Magellanic Cloud (LMC) to determine their mean metallicities and ages, as well as the mean metallicities of 80 surrounding fields. The study constructs an age-metallicity relation (AMR) for the LMC clusters. The results provide valuable information about the spatial distributions of clusters in the LMC and suggest a possible former interaction between the LMC and Small Magellanic Cloud (SMC).
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
H. Netzel, R. Smolec
Summary: In this study, a sample of high-amplitude delta Scuti stars from the OGLE inner bulge fields was used to determine their physical parameters by computing pulsation models and matching pulsation periods and period ratios. The distribution of physical parameters was presented and 16 candidates for SX Phoenicis stars were selected.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. Romagnolo, A. Olejak, A. Hypki, G. Wiktorowicz, K. Belczynski
Summary: This study aims to test the formation of the HR 6819 inner binary by simulating its evolution and comparing it to binary systems in the Galactic field and globular star clusters. The results showed that it is unlikely for the HR 6819-like binary system to form in globular clusters or in the Galactic field. Therefore, the presence of a dormant black hole in HR 6819 cannot be easily explained by current models based on isolated and dynamical binary evolution.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Colin Littlefield, D. W. Hoard, Peter Garnavich, Paula Szkody, Paul A. Mason, Simone Scaringi, Krystian Ilkiewicz, Mark R. Kennedy, Saul A. Rappaport, Rahul Jayaraman
Summary: We present long-duration, uninterrupted light curves of two magnetic cataclysmic variable stars with slightly desynchronized rotational frequencies. The first system, SDSS J084617.11+245344.1, exhibits a longer orbital period and a conspicuous beat period of 6.77 days. The second system, Paloma, displays a spin period of 2.27 hr and exhibits alternating single and double-humped light curves during the spin-orbit beat period. Rating: 8/10
ASTRONOMICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
R. Smolec, O. Ziolkowska, M. Ochalik, M. Sniegowska
Summary: We analyzed Optical Gravitational Lensing Experiment photometry to search for additional periodicities beyond radial modes in classical Cepheids in the Large and Small Magellanic Clouds. We found new candidates for double-mode radial pulsations as well as other signals that cannot be attributed to radial modes. The statistical properties of these signals were analyzed, and a significant fraction were identified as non-radial modes. The study also unveiled differences in additional frequency content between the two Clouds.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Evan B. Bauer, Josiah Schwab, R. Farmer, Warrick H. Ball, Earl P. Bellinger, Aaron Dotter, Meridith Joyce, Pablo Marchant, Joey S. G. Mombarg, William M. Wolf, Tin Long Sunny Wong, Giulia C. Cinquegrana, Eoin Farrell, R. Smolec, Anne Thoul, Matteo Cantiello, Falk Herwig, Odette Toloza, Lars Bildsten, Richard H. D. Townsend, F. X. Timmes
Summary: We have updated the capabilities of the MESA software by implementing automatic differentiation, improving the treatment of convection, enhancing the equation of state, and updating various aspects of stellar modeling. We have also introduced new methods to increase the efficiency of calculating opacities and radiative levitation, and to evolve the late stages of massive stars. Additionally, we have made improvements to the software infrastructure of MESA to enhance source code development and community engagement.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)