Article
Astronomy & Astrophysics
Wei-Min Liu, Long Jiang, Wen-Cong Chen, Xiang-Dong Li
Summary: The disc instability mechanism (DIM) is responsible for the transient behavior of dwarf novae (DNe), with duty cycles playing a crucial role in the long-term binary evolution. Through systematic investigation, it is found that a specific range of duty cycles is required for efficient white dwarf (WD) mass growth. While the DIM significantly influences the accretion process, none of the carbon-oxygen (CO) WDs in the simulations can reach the explosion mass of Type Ia supernovae. The DIM in DNe could partially alleviate the WD mass problem.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. Kahl, J. Jose, P. J. Woods
Summary: The study examined uncertainties in the calculation of the F-18(p, alpha) reaction rate, aiming to identify the factors that most affect the predicted abundance of F-18 ejected from novae. The research highlighted the highly uncertain nature of the F-18(p, alpha) rate at nova temperatures, emphasizing the need for future experimental work to focus on determining quantum properties of subthreshold states more precisely.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Kareem El-Badry, Hans-Walter Rix, Eliot Quataert, Thomas Kupfer, Ken J. Shen
Summary: A systematic survey identified 51 mass-transferring and recently detached cataclysmic variables with evolved secondaries, potentially progenitors of extremely low mass white dwarfs, AM CVn systems, and detached ultracompact binaries. Most found secondaries are hotter, with those above 7000 K being in a detached state, while those below 7000 K are still mass-transferring. This discovery triples the known evolved CV population and presents opportunities for enhancing understanding of compact binary populations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Pavel A. Denissenkov, Chris Ruiz, Sriteja Upadhyayula, Falk Herwig
Summary: Recent spectroscopic measurements reveal high abundances of Be-7 in nova ejecta, deviating from theoretical predictions, but the assumption of enhanced He-4 abundances helps reduce this discrepancy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Keith Inight, Boris T. Gaensicke, Elme Breedt, Henry T. Israel, Stuart P. Littlefair, Christopher J. Manser, Tom R. Marsh, Tim Mulvany, Anna Francesca Pala, John R. Thorstensen
Summary: We present a catalogue of 507 cataclysmic variables (CVs) observed in SDSS I to IV, including 70 new classifications. This sample provides unbiased space densities and period distributions for different CV sub-types. The study also reports on peculiar CVs, period bouncers, and CVs with large changes in accretion rates. The catalogue and material included in it will be useful for observational population studies of CVs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Natsuko Yamaguchi, Kareem El-Badry, Antonio C. Rodriguez, Maude Gull, Benjamin R. Roulston, Zachary P. Vanderbosch
Summary: In this study, follow-up spectroscopy of 21 cataclysmic variables (CVs) with evolved secondaries and ongoing or recently terminated mass transfer was conducted. The sodium (Na) abundances of the donors were measured to test evolutionary models, and it was found that all objects in the sample had enhanced Na abundances. Binary evolution models of CVs were used to interpret the results, which predicted Na enhancement in the donors' cores near the end of their main-sequence evolution. The observed [Na/H] values were on average approximately 0.3 dex higher than predicted by the models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
A. A. Nucita, S. M. Lezzi, F. De Paolis, F. Strafella, D. Licchelli, A. Franco, M. Maiorano
Summary: This passage discusses the characteristics and detection methods of intermediate polars, as well as the analysis results for five cataclysmic variable binary candidates. The study found that most of these candidates can be safely identified as intermediate polars, but one may belong to the polar subclass of cataclysmic variables.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Alex J. Kemp, Amanda Karakas, Andrew R. Casey, Robert G. Izzard, Ashley J. Ruiter, Poojan Agrawal, Floor S. Broekgaarden, Karel D. Temmink
Summary: This study presents valuable insights into novae phenomena and their evolutionary pathways, as well as simulation research on nova events, discussing the current annual rate of novae in M31 and the variation in II nova rates when common-envelope parameters are adjusted.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Kareem El-Badry, Eliot Quataert, Hans-Walter Rix, Daniel R. Weisz, Thomas Kupfer, Ken J. Shen, Maosheng Xiang, Yong Yang, Xiaowei Liu
Summary: A close binary system has been discovered consisting of a bloated, low-mass proto-white dwarf and a massive white dwarf companion. The proto-white dwarf is cooler and more puffy than any known extremely low-mass white dwarf, possibly undergoing ongoing or recently terminated mass transfer.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
D. Sahman, V. S. Dhillon
Summary: This paper reports on the second campaign to search for old nova shells around cataclysmic variables (CVs). No new shells were found based on the examination of Ha images of 47 objects. Combining the latest results with previous studies, the nova-like phase of the mass transfer cycle is estimated to last about 3000 years.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yunlang Guo, Chengyuan Wu, Bo Wang
Summary: This article investigates elemental abundance ratios during nova outbursts to estimate the white dwarf mixing fraction in classical novae. Results reveal four elemental abundance ratios that can be used to determine the mixing fraction, with (H + He)/ Sigma CNO being the most suitable indicator. Higher metallicity is associated with longer decline times during nova outbursts.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
K. P. Singh, V Girish, M. Pavana, Jan-Uwe Ness, G. C. Anupama, M. Orio
Summary: Two long observations were taken of the third recorded outburst of the symbiotic recurrent nova V3890 Sgr using the AstroSat Soft X-ray Telescope. The observations revealed unstable and variable behavior of the shock component and supersoft source (SSS) emission. The second observation showed an even brighter but still highly variable SSS component compared to the first observation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Thomas Siegert, Sohan Ghosh, Kalp Mathur, Ethan Spraggon, Akshay Yeddanapudi
Summary: Classical novae, although numerous, have never been observed in soft gamma-ray emission. This study aimed to constrain the ejecta masses of Be-7 and Na-22 from classical novae through their gamma-ray line emissions, and found that individual novae are too dim to be detectable, with uncertainties covering several orders of magnitude. Tight upper bounds on Na-22 ejecta masses were inferred within the Bayesian hierarchical model framework.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
P. Molaro, L. Izzo, V D'Odorico, E. Aydi, P. Bonifacio, G. Cescutti, E. J. Harvey, M. Hernanz, P. Selvelli, M. della Valle
Summary: We report on the search for the Be-7 ii isotope in the outbursts of the classical nova V6595 Sgr. The observations reveal the presence of Be-7 ii and other elements in the absorption lines of the outburst spectra. The abundance of Be-7 is about half of the value commonly measured in novae. The observations also classify the nova as ONe type.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
I Zaznobin, S. Sazonov, R. Burenin, G. Uskov, A. Semena, M. Gilfanov, P. Medvedev, R. Sunyaev, M. Eselevich
Summary: This study reports the discovery of three cataclysmic variables in the first year of the all-sky X-ray survey by the SRG orbital observatory. Through optical and X-ray analysis, their properties and characteristics are confirmed, and the orbital period of one of them is measured. This study is important for understanding the nature and distribution of cataclysmic variables.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
P. Molaro, L. Izzo, V D'Odorico, E. Aydi, P. Bonifacio, G. Cescutti, E. J. Harvey, M. Hernanz, P. Selvelli, M. della Valle
Summary: We report on the search for the Be-7 ii isotope in the outbursts of the classical nova V6595 Sgr. The observations reveal the presence of Be-7 ii and other elements in the absorption lines of the outburst spectra. The abundance of Be-7 is about half of the value commonly measured in novae. The observations also classify the nova as ONe type.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Engineering, Aerospace
J. Greiner, U. Laux
Summary: This study introduces a novel compact 4-channel beam splitter based on a combination of dichroic coatings and internal total reflection, similar to the interference double prism invented by Kosters 90 years ago. When used with a rapidly-slewing 50 cm telescope in space, it has the potential to double the number of gamma-ray bursts at high (> 5) redshift within 2 years.
CEAS SPACE JOURNAL
(2022)
Article
Astronomy & Astrophysics
F. Kunzweiler, B. Biltzinger, J. Greiner, J. M. Burgess
Summary: This study presents a new algorithm and automated data analysis pipeline for detecting slowly rising or long-duration transient events in high-energy electromagnetic sky. The algorithm demonstrates high sensitivity and coverage, and during testing on Fermi-GBM data, it successfully detected over 300 untriggered transient signals, one of which was confirmed to originate from a known astrophysical source.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
D. S. Aguado, P. Molaro, E. Caffau, J. Gonzalez Hernandez, M. R. Zapatero Osorio, P. Bonifacio, C. Allende Prieto, R. Rebolo, M. Damasso, A. Suarez Mascareno, S. B. Howell, E. Furlan, S. Cristiani, G. Cupani, P. Di Marcantonio, V D'Odorico, C. Lovis, C. J. A. P. Martins, D. Milakovic, M. T. Murphy, N. J. Nunes, F. Pepe, N. C. Santos, T. M. Schmidt, A. Sozzetti
Summary: This study used the ESPRESSO spectrograph to observe HE 0107-5240 and found that it is a binary star with a long period, providing important clues for the formation mechanism of the first generation of low-mass stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Luca Izzo, Paolo Molaro, Piercarlo Bonifacio, Gabriele Cescutti, Massimo Della Valle, Pierluigi Selvelli
Summary: CUBES is a new high-resolution spectrograph designed for the Very Large Telescope at the European Southern Observatory. It is primarily aimed at studying and characterizing the nucleosynthesis of beryllium. By directly identifying lithium in classical novae and observing the resonance transition of Be-7 II, CUBES can quantify the amount of Be-7 and Li-7 produced by different types of novae in the Milky Way and its nearby satellite galaxies. Additionally, it can provide insights into the properties of nova ejecta, the evolution of shocks in novae, and their connection to high-energy emission observed in these transients.
EXPERIMENTAL ASTRONOMY
(2023)
Article
Astronomy & Astrophysics
P. Molaro, L. Izzo, P. Selvelli, P. Bonifacio, E. Aydi, G. Cescutti, E. Guido, E. J. Harvey, M. Hernanz, M. Della Valle
Summary: The recurrent nova RS Oph had a new outburst in August 8, 2021, with a visible brightness of V = 4.8 mag. Observations of the outburst detected the presence of Be-7, possibly formed in thermonuclear runaway reactions. The estimated Be-7 yield was N(Be-7)/N(H) = 5.7 x 10(-6), which is among the lowest measured in classical novae. The detection of Be-7 in RS Oph supports the idea that novae are the main source of Li-7 in the Galaxy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. S. Aguado, E. Caffau, P. Molaro, C. Allende Prieto, P. Bonifacio, J. I. Gonzalez Hernandez, R. Rebolo, S. Salvadori, M. R. Zapatero Osorio, S. Cristiani, F. Pepe, N. C. Santos, G. Cupani, P. Di Marcantonio, V. D'Odorico, C. Lovis, N. J. Nunes, C. J. A. P. Martins, D. Milakovic, J. Rodrigues, T. M. Schmidt, A. Sozzetti, A. Suarez Mascareno
Summary: This article presents the characteristics and observational results of the carbon-enhanced metal-poor (CEMP) star SMSS J160540.18-144323.1, confirming its chemically unmixed nature and the lack of mass transfer from a binary companion based on the analysis of its radial velocity and isotopic ratio.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
R. Szakats, Cs. Kiss, J. L. Ortiz, N. Morales, A. Pal, T. G. Mueller, J. Greiner, P. Santos-Sanz, G. Marton, R. Duffard, P. Sagi, E. Forgacs-Dajka
Summary: The rotational states of dwarf planet-satellite systems in the trans-Neptunian region are influenced by formation conditions and tidal interaction. Observations indicate that the rotation of Eris is tidally locked to its satellite Dysnomia, with a period of 15.8 days. Simulations suggest that Dysnomia must have a relatively large mass and size to slow down Eris's rotation.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Thomas Siegert, Moritz M. M. Pleintinger, Roland Diehl, Martin G. H. Krause, Jochen Greiner, Christoph Weinberger
Summary: Diffuse gamma-ray line emission allows us to study the entire cycle of matter in the Milky Way, from nucleosynthesis in massive stars to their ejection and mixing in the interstellar medium. We developed a model called Population SYnthesis COde (PSYCO) that incorporates various parameters to simulate the distribution of nucleosynthesis ejecta. Our model suggests that a high star formation rate and a spiral-arm-dominated density profile are needed to explain the observed distribution of Al-26. The comparison of simulated morphologies with observational data implies frequent merging of superbubbles in the Milky Way and the presence of unknown foreground emission at 1.8 MeV.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
F. Calore, A. Dekker, P. D. Serpico, T. Siegert
Summary: Using the analysis method of INTEGRAL/SPI data and a dark matter spatial template, we investigate the constraints on dark matter candidates lighter than weakly interacting massive particles decaying into line or continuum electromagnetic final state channels. The obtained bounds are the strongest to date for dark matter masses between approximately 60 keV and 16 MeV, experiencing two-body decays producing photon lines.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
K. Sokolovsky, T. J. Johnson, S. Buson, P. Jean, C. C. Cheung, K. Mukai, L. Chomiuk, E. Aydi, B. Molina, A. Kawash, J. D. Linford, A. J. Mioduszewski, M. P. Rupen, J. L. Sokoloski, M. N. Williams, E. Steinberg, I Vurm, B. D. Metzger, K. L. Page, M. Orio, R. M. Quimby, A. W. Shafter, H. Corbett, S. Bolzoni, J. DeYoung, K. Menzies, F. D. Romanov, M. Richmond, J. Ulowetz, T. Vanmunster, G. Williamson, D. J. Lane, M. Bartnik, M. Bellaver, E. Bruinsma, E. Dugan, J. Fedewa, C. Gerhard, S. Painter, D-M Peterson, J. E. Rodriguez, C. Smith, H. Sullivan, S. Watson
Summary: V1674 Her is the fastest nova ever recorded that challenges our understanding of shock formation in novae. Through coordinated observations in different wavelengths, we found that the emission from V1674 Her can be explained by thermal and synchrotron radiation. Short-lived gamma-ray emission was detected in the 0.1-100 GeV range within 18 hours after the eruption of the nova began.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
E. J. Harvey, E. Aydi, L. Izzo, C. Morisset, M. J. Darnley, K. Fitzgerald, P. Molaro, F. Murphy-Glaysher, M. P. Redman, M. Shrestha
Summary: V906 Carinae is one of the best observed novae recently, with prolific dust production and shocks in the early ejecta outflow. This study examines the consequences of these early interactions through high-resolution Ultraviolet and Visual Echelle spectrograph spectroscopy, and investigates the formation of the final structure through extrapolation. The geometry and shaping history of the shell structure are analyzed using a spectral line SHAPE model fit, and spectral tracers of shocks and ionized environment are examined. Temperature, density, and abundance analyses of the evolving nova shell are presented.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Pablo Rodriguez-Gil, Jesus M. Corral-Santana, N. Elias-Rosa, Boris T. Gansicke, Margarita Hernanz, Gloria Sala
Summary: This study presents the first reliable determination of the orbital period of the recurrent nova V2487 Oph. The derived value is significantly shorter than previous claims, making V2487 Oph one of the longest period cataclysmic variables known. The analysis of the spectra suggests that the broad Balmer absorptions in V2487 Oph come from an accretion disc viewed at low inclination.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Paolo Molaro, Federico Bernardini
Summary: Chisel marks found on a stone in the Rupinpiccolo hill fort in northeastern Italy are suggested to represent the night sky. Analysis shows that some of these marks correspond to popular stellar asterisms, indicating intentional representation. The high correlation between these marks and stellar positions suggests ancient observations and recording of constellations. However, the identity of one mark remains unknown.
ASTRONOMISCHE NACHRICHTEN
(2023)