Article
Astronomy & Astrophysics
Christina K. Gilligan, Brian Chaboyer, Massimo Marengo, Joseph P. Mullen, Giuseppe Bono, Vittorio F. Braga, Juliana Crestani, Massimo Dall'Ora, Giuliana Fiorentino, Matteo Monelli, Jill R. Neeley, Michele Fabrizio, Clara E. Martinez-Vazquez, Frederic Thevenin, Christopher Sneden
Summary: Accurate metallicities of RR Lyrae stars were analyzed in this study using high-resolution spectra from the Southern African Large Telescope. The study presented new period-luminosity-metallicity relationships in WISE W1 and W2 magnitudes, as well as the Wesenheit magnitudes W(W1, V - W1) and W(W2, V- W2) by combining new spectroscopic abundances with literature determinations for 93 stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Thomas A. Molnar, Jason L. Sanders, Leigh C. Smith, Vasily Belokurov, Philip Lucas, Dante Minniti
Summary: The study introduces the VIVACE catalogue which extracts variable stars from the VVV infrared survey data through an automated classification pipeline. Utilizing a two-stage hierarchical classifier, the research identifies and classifies variable sources, resulting in a catalogue of approximately 1.4 million likely variable stars with different types and classification probabilities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. Marconi, R. Molinaro, V Ripepi, S. Leccia, I Musella, G. De Somma, M. Gatto, M. Moretti
Summary: Theoretical light curves in Gaia bands G, G(BP), and G(RP) for RR Lyrae pulsators are derived based on extended non-linear convective models. The effects of chemical composition on the derived parameters and Period-Wesenheit relations are discussed, and theoretical estimates of individual parallaxes for Galactic RR Lyrae in Gaia Data Release 2 are compared with astrometric solutions. A very small offset, consistent with zero, is required to reconcile the predicted distances with Gaia results.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Yoichi Takeda
Summary: The photospheric abundances of C, N, O, and Na in RR Lyr stars were studied to investigate the mixing mechanism in low-mass giant stars. The study confirmed the deficiency in C and enrichment in N in these stars, with the extent of peculiarities increasing with a decrease in metallicity. However, no apparent Na anomaly was observed, contradicting theoretical expectations. Further improvements in the current theory may be necessary.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. Arellano Ferro, F. C. Rojas Galindo, I. H. Bustos Fierro, S. Muneer, M. A. Yepez, Sunetra Giridhar
Summary: In this study, a 5-year CCD photometric VI time series of NGC 7006 was used to analyze the variable star population. Inconsistent classifications and sky coordinates were corrected, and 10 new cluster member variables were discovered. An independent estimate of reddening yielded a value of E(B-V) = 0.08 +/- 0.05. The cluster mean metallicity and distance were estimated using Fourier decompositions of RR Lyrae light curves and well-established calibrations, resulting in [Fe/H](ZW) = -1.53 +/- 0.15 and 41.2 +/- 1.4 kpc, respectively. Extensive membership analysis using Gaia DR3 data allowed for the identification of field stars and consideration of the variable distribution in the horizontal branch. The study also discussed the origin of CW stars and the mass loss of RR Lyrae stars during their evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
V. F. Braga, G. Fiorentino, G. Bono, P. B. Stetson, C. E. Martinez-Vazquez, S. Kwak, M. Tantalo, M. Dall'Ora, M. Di Criscienzo, M. Fabrizio, M. Marengo, S. Marinoni, P. M. Marrese, M. Monelli
Summary: We investigated the properties of mixed-mode RR Lyrae variables in the Fornax dwarf spheroidal galaxy and compared them with variables in the Magellanic Clouds and nearby dwarf spheroidals. We found that the ratio of mixed-mode RR Lyrae decreases with metallicity, and Fornax fills a period gap in the Petersen diagram similarly to Small Magellanic Cloud variables. Additionally, a new pulsation diagnostics method reveals that Large Magellanic Cloud variables can be separated into two groups with different evolutionary properties. Our findings suggest that Fornax and Sculptor dwarf spheroidals have undergone different chemical enrichment histories.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Matthew Raymond Gent, Maria Bergemann, Aldo Serenelli, Luca Casagrande, Jeffrey M. Gerber, Ulrike Heiter, Mikhail Kovalev, Thierry Morel, Nicolas Nardetto, Vardan Adibekyan, Victor Silva Aguirre, Martin Asplund, Kevin Belkacem, Carlos del Burgo, Lionel Bigot, Andrea Chiavassa, Luisa Fernanda Rodriguez Diaz, Marie-Jo Goupil, Jonay I. Gonzalez Hernandez, Denis Mourard, Thibault Merle, Szabolcs Meszaros, Douglas J. Marshall, Rhita-Maria Ouazzani, Bertrand Plez, Daniel Reese, Regner Trampedach, Maria Tsantaki
Summary: The SAPP pipeline is introduced as a prototype code for determining parameters of stars observed within the PLATO space mission. It uses a Bayesian inference method to provide various stellar parameters and can be applied to a wider range of stellar types. By combining multiple observables, the code is able to break degeneracies between parameters and obtain more accurate values and realistic uncertainties. Results show that combining the nu(max) scaling relation with stellar spectra yields the best results.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Ata Sarajedini, Sevinc Gokmen
Summary: This study compares two relations for calculating the metal abundance of ab-type RR Lyrae variables and determines that knowing only the period of these variables is sufficient to determine the mean metallicity of a globular cluster. Both tested equations accurately reproduce the spectroscopic metal abundance of each cluster, with an accuracy of ±0.28 dex.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
G. Nandakumar, N. Ryde, L. Casagrande, G. Mace
Summary: This study develops a method for determining the stellar parameters of M giants from NIR spectra. The accuracy and precision of the method are validated through observations of nearby well-studied M giants and comparisons with existing data. The results show good agreement and provide insights into the abundance trends of alpha-elements in solar neighborhood M giants.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
L-J Li, S-B Qian, L-Y Zhu
Summary: This study reanalyzed the c-type RR Lyrae star BE Dor that showed cyclic period changes and found that these changes are quasi-periodic and abrupt, which cannot be explained by the light-traveltime effect. The study suggests that the period modulation in BE Dor may be caused by the interaction between turbulent convection and magnetic field activity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Geza Kovacs, Behrooz Karamiqucham
Summary: The study combines observational data with models to derive average luminosities for RR Lyrae stars and finds that they are in agreement with high accuracy parallax measurements. However, about 10% of the sample shows a curious distance keeping behavior between evolutionary and pulsation models, which may be addressed by increasing reddening excessively.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Giovanni Motta, Darlin Soto, Marcio Catelan
Summary: This paper introduces a new mathematical model for describing modulated light curves in periodic variable stars, which considers smoothly time-varying trends and harmonic components. The proposed method offers flexibility and avoids restrictive assumptions about the functional form of the trends and amplitudes. The authors develop a semi-parametric method for estimating the time-varying parameters and derive the mathematical definition of spectral density for unequally spaced time series to detect serial correlation in the residuals.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
L. -J. Li, S. -B. Qian, L. -Y. Zhu, J. -J. He, X. -H. Fang
Summary: The pulsation period of RR Lyrae star AX UMa is rapidly decreasing with a rate of -7.752 ± 0.005 days per million years, making it the fastest-period decreasing ab-type RR Lyrae star in the Galactic field. The O-C residuals suggest additional periodic variations potentially caused by the star orbiting in a binary system, with the lower mass limit of the companion estimated at about 1 M. The special characteristics of AX UMa, along with the absence of a bump in its light curves indicating mass loss in the outer atmosphere, make it deserving of more attention and further observations.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Gaochao Liu, Yang Huang, Sarah Ann Bird, Huawei Zhang, Fei Wang, Haijun Tian
Summary: Based on a large spectroscopic sample of RR Lyrae stars, this study provides a detailed analysis of the chemical and kinematic properties of the Galactic halo, revealing distinct features between the inner and outer halo components. The inner halo is dominated by a metal-rich population with extreme radial anisotropy, possibly originating from a ancient merged satellite. The outer halo shows a broad metallicity distribution with weak peaks and a uniform anisotropy value.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Gustavo E. Medina, Camilla J. Hansen, Ricardo R. Munoz, Eva K. Grebel, A. Katherina Vivas, Jeffrey L. Carlin, Clara E. Martinez-Vazquez
Summary: We conducted spectroscopic analysis of 20 halo ab-type RR Lyrae stars using medium-resolution spectra, obtaining systemic velocities of targets with uncertainties of 5-10 km s(-1) and calculating orbital parameters for a subsample. Our findings suggest that at least half of the sample stars might have an accreted origin, based on their orbital orientations in an isolated Milky Way or a perturbed model by the Large Magellanic Cloud. We also derived atmospheric parameters and chemical abundance ratios for seven stars beyond 20 kpc, with some displaying underabundance of alpha-elements, indicating association with accretion events.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. Sebastian, M. I. Swayne, P. F. L. Maxted, A. H. M. J. Triaud, S. G. Sousa, G. Olofsson, M. Beck, N. Billot, S. Hoyer, S. Gill, N. Heidari, D. V. Martin, C. M. Persson, M. R. Standing, Y. Alibert, R. Alonso, G. Anglada, J. Asquier, T. Barczy, D. Barrado, S. C. C. Barros, M. P. Battley, W. Baumjohann, T. Beck, W. Benz, M. Bergomi, I. Boisse, X. Bonfils, A. Brandeker, C. Broeg, J. Cabrera, S. Charnoz, A. Collier Cameron, Sz Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. D. S. Demangeon, B-O Demory, G. Dransfield, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Guedel, J. Hasiba, G. Hebrard, K. Heng, K. G. Isaak, L. L. Kiss, E. Kopp, V. Kunovac, J. Laskar, A. Lecavelier des Etangs, M. Lendl, C. Lovis, D. Magrin, J. McCormac, N. J. Miller, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Palle, F. A. Pepe, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, S. Lalitha, A. Santerne, N. C. Santos, G. Scandariato, D. Segransan, A. E. Simon, A. M. S. Smith, M. Steller, Gy M. Szabo, N. Thomas, S. Udry, V. Van Grootel, N. A. Walton
Summary: Eclipsing binaries are important benchmark objects for testing stellar structure and evolution models, particularly for fully convective M-dwarfs. This study analyzed five low-mass stellar companion eclipsing binaries using ultra-high-precision light curves from the CHEOPS satellite. The results showed good agreement with theoretical predictions, with a radius accuracy better than 1% and a surface gravity accuracy better than 0.2%. Precise orbits from radial velocity measurements were found to be crucial for accurately determining M-dwarf radii below 5% accuracy. These findings contribute valuable data points to the mass-radius diagram of fully convective M-dwarfs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Monika Jurkovic, Emese Plachy, Laszlo Molnar, Martin A. T. Groenewegen, Attila Bodi, Pawel Moskalik, Robert Szabo
Summary: We presented the results of analyzing Type II and anomalous Cepheids using data from the Kepler K2 mission. The precise light curves of these pulsating variable stars are essential for studying their pulsation details and effects. The analysis included Fourier analysis of the light curves and determining physical parameters through model fitting. The study also compared the stars with evolutionary models and found the presence of period doubling and modulation effects.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
B-O Demory, S. Sulis, E. Meier Valdes, L. Delrez, A. Brandeker, N. Billot, A. Fortier, S. Hoyer, S. G. Sousa, K. Heng, M. Lendl, A. Krenn, B. M. Morris, J. A. Patel, Y. Alibert, R. Alonso, G. Anglada, T. Barczy, D. Barrado, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, X. Bonfils, C. Broeg, M. Buder, J. Cabrera, S. Charnoz, A. Collier Cameron, H. Cottard, Sz Csizmadia, M. B. Davies, M. Deleuil, O. D. S. Demangeon, D. Ehrenreich, A. Erikson, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Guedel, K. G. Isaak, L. L. Kiss, J. Laskar, A. Lecavelier des Etangs, C. Lovis, A. Luntzer, D. Magrin, L. Marafatto, P. F. L. Maxted, V Nascimbeni, G. Olofsson, R. Ottensamer, I Pagano, E. Palle, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I Ribas, N. C. Santos, G. Scandariato, D. Segransan, A. E. Simon, A. M. S. Smith, M. Steller, Gy M. Szabo, N. Thomas, S. Udry, V. Van Grootel, N. A. Walton
Summary: In this study, occultation observations of the super-Earth 55 Cnc e were analyzed using the CHEOPS satellite, and the detection of occultation with an average depth of 12 +/- 3 ppm was reported. The geometric albedo of 55 Cnc e was estimated to be A(g) < 0.55 after removing the thermal emission measured by Spitzer at 4.5 μm. The photometric performance of CHEOPS enabled the detection of individual occultations in the visible and identified short-timescale photometric corrugations likely caused by stellar granulation. A clear sinusoidal pattern with a period of 47.3 days was also found, whose planetary origin could be tested with upcoming JWST occultation observations.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
J. -V. Harre, A. M. S. Smith, S. C. C. Barros, G. Boue, Sz. Csizmadia, D. Ehrenreich, H. -G. Floren, A. Fortier, P. F. L. Maxted, M. J. Hooton, B. Akinsanmi, L. M. Serrano, N. M. Rosario, B. -O. Demory, K. Jones, J. Laskar, V. Adibekyan, Y. Alibert, R. Alonso, D. R. Anderson, G. Anglada, J. Asquier, T. Barczy, D. Barrado y Navascues, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, F. Biondi, A. Bonfanti, X. Bonfils, A. Brandeker, C. Broeg, J. Cabrera, V. Cessa, S. Charnoz, A. Collier Cameron, M. B. Davies, M. Deleuil, L. Delrez, O. D. S. Demangeon, A. Erikson, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Guedel, C. Hellier, K. Heng, S. Hoyer, K. G. Isaak, L. L. Kiss, A. Lecavelier des Etangs, M. Lendl, C. Lovis, A. Luntzer, D. Magrin, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Palle, C. M. Persson, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. R. Ricker, S. Salmon, N. C. Santos, G. Scandariato, S. Seager, D. Segransan, A. E. Simon, S. G. Sousa, M. Steller, Gy. M. Szabo, N. Thomas, S. Udry, B. Ulmer, V. Van Grootel, N. A. Walton, T. G. Wilson, J. N. Winn, B. Wohler
Summary: This study aims to investigate tidal orbital decay in the KELT-9, KELT-16, WASP-4, and HD 97658 systems. The Q' (low asterisk) value for each star is constrained, while the existence of TTVs in the HD 97658 system is tested. Photometric observations from CHEOPS and TESS, combined with archival data, are analyzed using MCMC algorithms to fit different models.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
F. Kiefer, V. Van Grootel, A. Lecavelier des Etangs, Gy. M. Szabo, A. Brandeker, C. Broeg, A. Collier Cameron, A. Deline, G. Olofsson, T. G. Wilson, S. G. Sousa, D. Gandolfi, G. Hebrard, Y. Alibert, R. Alonso, G. Anglada, T. Barczy, D. Barrado, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, J. Cabrera, S. Charnoz, Sz. Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. D. S. Demangeon, B. -o. Demory, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, M. Gillon, M. Guedel, K. Heng, S. Hoyer, K. G. Isaak, L. L. Kiss, J. Laskar, M. Lendl, C. Lovis, D. Magrin, P. F. L. Maxted, M. Munari, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Palle, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, C. Reimers, I. Ribas, N. C. Santos, G. Scandariato, D. Segransan, A. E. Simon, A. M. S. Smith, M. Steller, N. Thomas, S. Udry, I. Walter, N. A. Walton
Summary: HD172555 is a young A7V star with a 10 au wide debris disk, potentially formed by collisions between large planetesimals. Spectroscopy has detected evaporating bodies, or exocomets, in this system, making it another possible example of a system experiencing heavy bombardment of planetesimals. By using transit photometry, the researchers aim to determine the dust content of these small bodies. Through a 2-day photometric monitoring with the CHEOPS space telescope, they found evidence of a transient absorption, corresponding to an exocomet passing near the star with similar properties to those previously detected in this system.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
J. Blanco-Pozo, M. Perger, M. Damasso, G. Anglada Escude, I. Ribas, D. Baroch, J. A. Caballero, C. Cifuentes, S. V. Jeffers, M. Lafarga, A. Kaminski, S. Kaur, E. Nagel, V. Perdelwitz, M. Perez-Torres, A. Sozzetti, D. Vigano, P. J. Amado, G. Andreuzzi, V. J. S. Bejar, E. L. Brown, F. Del Sordo, S. Dreizler, D. Galadi-Enriquez, A. P. Hatzes, M. Kuerster, A. F. Lanza, A. Melis, E. Molinari, D. Montes, M. Murgia, E. Palle, L. Pena-Monino, D. Perrodin, M. Pilia, E. Poretti, A. Quirrenbach, A. Reiners, A. Schweitzer, M. R. Zapatero Osorio, M. Zechmeister
Summary: A companion with M > 10.6 M-circle plus to GJ 1151 was discovered in a 390-day orbit at a distance of 0.57 au from the primary star using LOFAR observations. Evidence for a second modulation is present, possibly due to long-term magnetic variability or a second substellar companion. The star exhibits elevated magnetic activity, one of which could be linked to the observed LOFAR radio emission. It is unlikely that GJ 1151 c or any additional outer companion is the source of the detected signal, but the possibility of an undetected short-period planet related to the radio emission cannot be ruled out, with an upper mass limit of 1.2 M-circle plus established.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
S. Sulis, M. Lendl, H. M. Cegla, L. F. Rodriguez Diaz, L. Bigot, V. Van Grootel, A. Bekkelien, A. Collier Cameron, P. F. L. Maxted, A. E. Simon, C. Lovis, G. Scandariato, G. Bruno, D. Nardiello, A. Bonfanti, M. Fridlund, C. M. Persson, S. Salmon, S. G. Sousa, T. G. Wilson, A. Krenn, S. Hoyer, A. Santerne, D. Ehrenreich, Y. Alibert, R. Alonso, G. Anglada, T. Barczy, D. Barrado y Navascues, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, L. Borsato, A. Brandeker, C. Broeg, J. Cabrera, S. Charnoz, C. Corral van Damme, Sz Csizmadia, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, O. D. S. Demangeon, B-O Demory, A. Erikson, A. Fortier, L. Fossati, D. Gandolfi, M. Gillon, M. Guedel, K. Heng, K. G. Isaak, L. L. Kiss, J. Laskar, A. Lecavelier des Etangs, D. Magrin, M. Munari, V Nascimbeni, G. Olofsson, R. Ottensamer, I Pagano, E. Palle, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I Ribas, M. Rieder, N. C. Santos, D. Segransan, A. M. S. Smith, M. Steinberger, M. Steller, Gy M. Szabo, N. Thomas, S. Udry, N. A. Walton, D. Wolter
Summary: This study aims to detect the signatures of stellar granulation, linking spectroscopic and photometric signatures for main-sequence stars and testing predictions from 3D hydrodynamic models. By observing two bright stars with high precision and comparing the results with other observations and models, the characteristics and properties of stellar granulation were determined. This research is important for future missions and high-precision radial velocity surveys.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Viktoria Kecskemethy, Csaba Kiss, Robert Szakats, Andras Pal, Gyula M. Szabo, Laszlo Molnar, Krisztian Sarneczky, Jozsef Vinko, Robert Szabo, Gabor Marton, Aniko Farkas-Takacs, Csilla E. Kalup, Laszlo L. Kiss
Summary: This paper presents the results of K2 observations of 66 trans-Neptunian objects, revealing new identifications and evidence of slow rotation. The detectability rate of light-curve periods was only 56%, lower than other small-body populations. Surprisingly, the trans-Neptunian objects showed higher light-curve amplitudes at larger sizes, in contrast to the expected behavior.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
V. Vanlaer, C. Aerts, E. P. Bellinger, J. Christensen-Dalsgaard
Summary: Gravity-mode pulsators have improved our understanding of mixing in intermediate mass stars. However, theoretical pulsation periods of stellar models often do not match observations, making it difficult to determine how these models should be improved. Inversions provide a way to probe the internal structure of these stars and identify areas in need of improvement. This study explores the feasibility of inversions for gravity-mode pulsators, specifically focusing on slowly rotating slowly pulsating B-type stars.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
V. Hocde, R. Smolec, P. Moskalik, O. Ziolkowska, R. Singh Rathour
Summary: This study establishes new empirical relations for estimating the iron content of classical Cepheids based on Fourier parameters from the V- and I-band light curves. These relations are applied to Cepheids in the Milky Way, Small Magellanic Cloud, and Large Magellanic Cloud. The results show small errors in the V- and I-band light curves and are consistent with literature values.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Justin A. Kader, Catherine A. Pilachowski, Christian I. Johnson, R. Michael Rich, Michael D. Young, Iulia T. Simion, William I. Clarkson, Scott Michael, Andrea Kunder, Anna Katherina Vivas, Andreas J. Koch-Hansen, Tommaso Marchetti
Summary: We present wide-field, high resolution maps of the color excess for 14 globular clusters toward the Southern Galactic bulge. These maps trace interstellar extinction by dust down to 5'' scales and show residual broadening in the color-magnitude diagrams for the target globular clusters. The broadening is likely driven by star-to-star elemental abundance variations.
ASTROPHYSICAL JOURNAL
(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)
Article
Astronomy & Astrophysics
Gabor B. Kovacs, Janos Nuspl, Robert Szabo
Summary: Despite the development of two- and three-dimensional models, numerical hydrocodes used for modeling stellar pulsations still rely on simplified one-dimensional stellar envelope models. This study compares two one-dimensional numerical codes with observations of radial-velocity of RRab stars and determines the undetermined convective parameters. The results show temperature dependence of some parameters and degeneracy between parameters, providing suggestions for the widely used RSP code in the MESA package.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Y. El Jariri, F. L. Sefyani, A. Benhida, Z. Benkhaldoun, K. Kolenberg, K. Chafouai, A. Habib, M. Sabil
Summary: We conducted a campaign of measurements of variable star spectra at the Oukaimeden observatory since 2013 and developed a graphical interface using Python to analyze the data. The interface can represent spectroscopic data graphically and determine parameters for the study of short-period variable stars. It can also convert Fits files into text files and create Excel tables containing calculated parameters.
ASTRONOMY AND COMPUTING
(2023)