P. Jia, Zhimin Yang, Z. Shang, Yong Yu, Jianhai Zhao
Photo-plates are an invaluable historical legacy that have been used for over a hundred years to capture images of celestial objects. By digitizing these photo-plates and processing the images with digital image processing methods, scientists can study celestial objects that exhibit temporal variations. Multiple-exposure photo-plates are a unique type of observation data that can capture images of the same sky at different observation times in a single photo-plate. Such photo-plates can be used to discover flares or moving targets with rapid variations, but they are difficult to process automatically due to their complex observation strategies. This paper proposes a pipeline based on classical data-processing algorithms and machine-learning algorithms to detect flares or moving targets in multiple-exposure photo-plate images automatically. The pipeline was used to process several digitized multiple-exposure photo-plate images from the China Astronomical Plates Data, and preliminary results indicate that the pipeline is effective. In the future, we plan to use our method to discover more celestial objects with temporal variations from photo-plate digital archives.
{"title":"Data processing pipeline for multiple-exposure photo-plate digital archives","authors":"P. Jia, Zhimin Yang, Z. Shang, Yong Yu, Jianhai Zhao","doi":"10.1093/pasj/psad038","DOIUrl":"https://doi.org/10.1093/pasj/psad038","url":null,"abstract":"\u0000 Photo-plates are an invaluable historical legacy that have been used for over a hundred years to capture images of celestial objects. By digitizing these photo-plates and processing the images with digital image processing methods, scientists can study celestial objects that exhibit temporal variations. Multiple-exposure photo-plates are a unique type of observation data that can capture images of the same sky at different observation times in a single photo-plate. Such photo-plates can be used to discover flares or moving targets with rapid variations, but they are difficult to process automatically due to their complex observation strategies. This paper proposes a pipeline based on classical data-processing algorithms and machine-learning algorithms to detect flares or moving targets in multiple-exposure photo-plate images automatically. The pipeline was used to process several digitized multiple-exposure photo-plate images from the China Astronomical Plates Data, and preliminary results indicate that the pipeline is effective. In the future, we plan to use our method to discover more celestial objects with temporal variations from photo-plate digital archives.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"88 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78853412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Yamagishi, K. Furuya, H. Sano, Natsuko Izumi, T. Takekoshi, H. Kaneda, K. Nakanishi, T. Shimonishi
We examine spatial variations of the C0$/$CO abundance ratio (XC/CO) in the vicinity of the γ-ray supernova remnant W 51 C, based on [C i] (3P1–3P0), 12CO(1–0), and 13CO(1–0) observations with the ASTE and Nobeyama 45 m telescopes. We find that XC/CO varies in a range of 0.02–0.16 (0.05 in median) inside the molecular clouds of AV > 100 mag, where photodissociation of CO by the interstellar UV is negligible. Furthermore, XC/CO is locally enhanced by a factor of up to four near the W 51 C center, depending on the projected distance from the W 51 C center. In high-AV molecular clouds, XC/CO is determined by the ratio of the cosmic-ray (CR) ionization rate to the H2 density, and we find no clear spatial variation of the H2 density against the projected distance. Hence, the high CR ionization rate may locally enhance XC/CO near the W 51 C center. We also find that the observed spatial extent of the enhanced XC/CO (∼17 pc) is consistent with the diffusion distance of CRs with an energy of 100 MeV. This fact suggests that the low-energy CRs accelerated in W 51 C enhance XC/CO. The CR ionization rate in the XC/CO-enhanced cloud is estimated to be 3 × 10−16 s−1 on the basis of time-dependent photodissociation region simulations of XC/CO, the value of which is 30 times higher than that in the standard Galactic environment. These results demonstrate that [C i] is a powerful probe to investigate the interaction between CRs and the interstellar medium for a wide area in the vicinity of supernova remnants.
{"title":"Cosmic-ray-driven enhancement of the C0/CO abundance ratio in W 51 C","authors":"M. Yamagishi, K. Furuya, H. Sano, Natsuko Izumi, T. Takekoshi, H. Kaneda, K. Nakanishi, T. Shimonishi","doi":"10.1093/pasj/psad046","DOIUrl":"https://doi.org/10.1093/pasj/psad046","url":null,"abstract":"\u0000 We examine spatial variations of the C0$/$CO abundance ratio (XC/CO) in the vicinity of the γ-ray supernova remnant W 51 C, based on [C i] (3P1–3P0), 12CO(1–0), and 13CO(1–0) observations with the ASTE and Nobeyama 45 m telescopes. We find that XC/CO varies in a range of 0.02–0.16 (0.05 in median) inside the molecular clouds of AV > 100 mag, where photodissociation of CO by the interstellar UV is negligible. Furthermore, XC/CO is locally enhanced by a factor of up to four near the W 51 C center, depending on the projected distance from the W 51 C center. In high-AV molecular clouds, XC/CO is determined by the ratio of the cosmic-ray (CR) ionization rate to the H2 density, and we find no clear spatial variation of the H2 density against the projected distance. Hence, the high CR ionization rate may locally enhance XC/CO near the W 51 C center. We also find that the observed spatial extent of the enhanced XC/CO (∼17 pc) is consistent with the diffusion distance of CRs with an energy of 100 MeV. This fact suggests that the low-energy CRs accelerated in W 51 C enhance XC/CO. The CR ionization rate in the XC/CO-enhanced cloud is estimated to be 3 × 10−16 s−1 on the basis of time-dependent photodissociation region simulations of XC/CO, the value of which is 30 times higher than that in the standard Galactic environment. These results demonstrate that [C i] is a powerful probe to investigate the interaction between CRs and the interstellar medium for a wide area in the vicinity of supernova remnants.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87128191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the geometric property of a scalar position function, the so-called force-free α, to see how it quantitatively characterizes the magnetic structure of solar active regions, which is reminiscent of the electrostatic potential whose geometric property provides information on the structure of electrified objects. Scatter plots of (α, ∇2α) show characteristic shapes representing twisted magnetic field configurations in two model active regions, one of which is formed by an emerging magnetic flux tube composed of strongly twisted field lines while the other is formed by a weakly twisted flux tube. By generalizing the concept of an axis field line in a uniformly twisted cylindrical flux tube, we introduce a topological object called the principal field line to represent magnetic structure reconstructed using a force-free field model. The principal field line and associated scatter plot of (α, ∇2α) provide a method reminiscent of active-region radiography, which could be used for quantitative classification of active regions with those magnetic configurations responsible for heating coronal plasmas, generating solar winds, and producing potentially harmful coronal explosive phenomena.
{"title":"Magnetic configurations related to the coronal heating and solar wind generation. II. Quantitative characterization of active-region magnetic structure based on the geometric property of force-free α","authors":"Yeonwoo Jang, Sibaek Yi, T. Magara","doi":"10.1093/pasj/psad035","DOIUrl":"https://doi.org/10.1093/pasj/psad035","url":null,"abstract":"\u0000 We investigate the geometric property of a scalar position function, the so-called force-free α, to see how it quantitatively characterizes the magnetic structure of solar active regions, which is reminiscent of the electrostatic potential whose geometric property provides information on the structure of electrified objects. Scatter plots of (α, ∇2α) show characteristic shapes representing twisted magnetic field configurations in two model active regions, one of which is formed by an emerging magnetic flux tube composed of strongly twisted field lines while the other is formed by a weakly twisted flux tube. By generalizing the concept of an axis field line in a uniformly twisted cylindrical flux tube, we introduce a topological object called the principal field line to represent magnetic structure reconstructed using a force-free field model. The principal field line and associated scatter plot of (α, ∇2α) provide a method reminiscent of active-region radiography, which could be used for quantitative classification of active regions with those magnetic configurations responsible for heating coronal plasmas, generating solar winds, and producing potentially harmful coronal explosive phenomena.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83536132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chu-Qi Wu, S. Qian, Fu-Xing Li, Li-ying Zhu, E. Zhao, W. Liao
To study massive binaries in different evolution stages or environments, we use the Small Magellanic Cloud (SMC) as our target because the metallicity in the SMC is much lower than that in our Milky Way. The period change of early-type close binary systems in the SMC was studied based on OGLE collections. Six of these systems are found to have periodic period changes. Since all of them are of early type, the light-traveltime effect probably created by these massive binaries with third bodies is used to explain such a phenomenon. We use the Wilson–Devinney code (WD method) to analyze their I-band photometric light curves. The results show the six third bodies as having orbital periods from 6.41–24.65 yr and minimum masses from 0.31–4.11 M⊙. Among all six systems, three have a negative $dot{P}$, which means that their periods keep decreasing. In addition, from the WD result, we find there are three deep-contact binaries, one intermediate-contact binary, and two shallow-contact binaries. The fraction of companions in massive contact binaries is quite high based on this sample, which may demonstrate the notion of high multiplicity in massive binary stars. This might mean that additional components may play an important role in the evolution of massive close binaries.
{"title":"Detection of six massive contact binaries with tertiary component candidates in the Small Magellanic Cloud","authors":"Chu-Qi Wu, S. Qian, Fu-Xing Li, Li-ying Zhu, E. Zhao, W. Liao","doi":"10.1093/pasj/psad037","DOIUrl":"https://doi.org/10.1093/pasj/psad037","url":null,"abstract":"\u0000 To study massive binaries in different evolution stages or environments, we use the Small Magellanic Cloud (SMC) as our target because the metallicity in the SMC is much lower than that in our Milky Way. The period change of early-type close binary systems in the SMC was studied based on OGLE collections. Six of these systems are found to have periodic period changes. Since all of them are of early type, the light-traveltime effect probably created by these massive binaries with third bodies is used to explain such a phenomenon. We use the Wilson–Devinney code (WD method) to analyze their I-band photometric light curves. The results show the six third bodies as having orbital periods from 6.41–24.65 yr and minimum masses from 0.31–4.11 M⊙. Among all six systems, three have a negative $dot{P}$, which means that their periods keep decreasing. In addition, from the WD result, we find there are three deep-contact binaries, one intermediate-contact binary, and two shallow-contact binaries. The fraction of companions in massive contact binaries is quite high based on this sample, which may demonstrate the notion of high multiplicity in massive binary stars. This might mean that additional components may play an important role in the evolution of massive close binaries.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"20 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82875234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Michiyama, Ming-Yang Zhuang, J. Shangguan, Hassen M. Yesuf, H. Kaneko, L. Ho
We have performed CO J = 1–0 observations of 10 galaxies hosting luminous (Lbol > 1046 erg s−1) type 1 active galactic nuclei (AGNs) with the Nobeyama 45 m radio telescope. The targets are selected because they are expected to be rich in molecular gas based on their high nebular dust extinction (AV). However, no significant CO emission lines were detected in any of the targets. The upper limits of the CO J = 1–0 luminosities are lower than expected given the molecular gas mass inferred from the nebular AV. This inconsistency may be due to overestimated AV values due to the lack of stellar absorption correction. Considering more reliable AV values, the CO J = 1–0 non-detections by Nobeyama 45 m are natural. This suggests that our results do not contradict the conversion methods from AV to molecular gas mass proposed in the literature. This survey suggests that careful AV measurements as well as CO observations are still needed to improve the measurements or estimates of the molecular gas content of galaxies hosting luminous AGNs.
{"title":"Nobeyama 45 m CO J = 1–0 observations of luminous type 1 AGNs at z ≈ 0.3","authors":"T. Michiyama, Ming-Yang Zhuang, J. Shangguan, Hassen M. Yesuf, H. Kaneko, L. Ho","doi":"10.1093/pasj/psad039","DOIUrl":"https://doi.org/10.1093/pasj/psad039","url":null,"abstract":"\u0000 We have performed CO J = 1–0 observations of 10 galaxies hosting luminous (Lbol > 1046 erg s−1) type 1 active galactic nuclei (AGNs) with the Nobeyama 45 m radio telescope. The targets are selected because they are expected to be rich in molecular gas based on their high nebular dust extinction (AV). However, no significant CO emission lines were detected in any of the targets. The upper limits of the CO J = 1–0 luminosities are lower than expected given the molecular gas mass inferred from the nebular AV. This inconsistency may be due to overestimated AV values due to the lack of stellar absorption correction. Considering more reliable AV values, the CO J = 1–0 non-detections by Nobeyama 45 m are natural. This suggests that our results do not contradict the conversion methods from AV to molecular gas mass proposed in the literature. This survey suggests that careful AV measurements as well as CO observations are still needed to improve the measurements or estimates of the molecular gas content of galaxies hosting luminous AGNs.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"17 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74909941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RZ Hor (TIC 31653503) is a long-period (P = 6.68 d) EA-type eclipsing binary that exhibits both chromospheric activity and oscillation. The physical properties of RZ Hor are determined with binary modelling for the first time. It is found that it has a semi-detached configuration with a low mass ratio of q = 0.1606(13), where the secondary component is filled with its Roche lobe. By analyzing all available eclipse times, it is shown that the orbital period of RZ Hor is decreasing at a rate of dP/dt = −5.48 × 10−6 d yr−1. In a typical Algol, a rapid mass transfer from the secondary to the primary should cause the orbital period to be increasing and then the secondary will be temporarily detached from the critical Roche lobe. The present configuration reveals that RZ Hor has undergone a rapid mass transfer and the period decrease can be explained by magnetic stellar wind. We estimate the rate of mass loss initially to be $10^{-8}, M_{odot }, mathrm{yr}^{-1} < vert dot{M}vert < 10^{-6}, M_{odot }$ yr−1. The variations and the asymmetries of the light curve are interpreted by adding a migrating cool spot on the surface of the late-type secondary. After subtracting the eclipsing changes from the light curve data, we analyzed the pulsation in the light residuals. Twenty-five frequencies of signal-to-noise amplitude ratio (S/N) larger than 5.2, including four multiples of tidally split frequencies, were detected. A total of 17 independent frequencies containing 2 radial modes, and 10 non-radial p modes were identified. All the investigations suggest that RZ Hor is an evolved Algol-type binary with a δ Sct-type primary and an active secondary.
{"title":"Photometric analysis on RZ Horologii: An evolved and active Algol with a δ Scuti component","authors":"Huiting Zhang, Shengbang Qian, Wen-shuo Liao","doi":"10.1093/pasj/psad033","DOIUrl":"https://doi.org/10.1093/pasj/psad033","url":null,"abstract":"\u0000 RZ Hor (TIC 31653503) is a long-period (P = 6.68 d) EA-type eclipsing binary that exhibits both chromospheric activity and oscillation. The physical properties of RZ Hor are determined with binary modelling for the first time. It is found that it has a semi-detached configuration with a low mass ratio of q = 0.1606(13), where the secondary component is filled with its Roche lobe. By analyzing all available eclipse times, it is shown that the orbital period of RZ Hor is decreasing at a rate of dP/dt = −5.48 × 10−6 d yr−1. In a typical Algol, a rapid mass transfer from the secondary to the primary should cause the orbital period to be increasing and then the secondary will be temporarily detached from the critical Roche lobe. The present configuration reveals that RZ Hor has undergone a rapid mass transfer and the period decrease can be explained by magnetic stellar wind. We estimate the rate of mass loss initially to be $10^{-8}, M_{odot }, mathrm{yr}^{-1} < vert dot{M}vert < 10^{-6}, M_{odot }$ yr−1. The variations and the asymmetries of the light curve are interpreted by adding a migrating cool spot on the surface of the late-type secondary. After subtracting the eclipsing changes from the light curve data, we analyzed the pulsation in the light residuals. Twenty-five frequencies of signal-to-noise amplitude ratio (S/N) larger than 5.2, including four multiples of tidally split frequencies, were detected. A total of 17 independent frequencies containing 2 radial modes, and 10 non-radial p modes were identified. All the investigations suggest that RZ Hor is an evolved Algol-type binary with a δ Sct-type primary and an active secondary.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"48 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87826756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atsushi Yasuda, N. Kuno, K. Sorai, K. Muraoka, Y. Miyamoto, H. Kaneko, Yoshiyuki Yajima, Takahiro Tanaka, K. Morokuma-Matsui, T. Takeuchi, Masato I. N. Kobayashi
We simultaneously measured the spatially resolved CO-to-H2 conversion factor (αCO) and dust-to-gas ratio (DGR) in nearby galaxies on a kiloparsec scale. In this study, we used 12CO(J = 1–0) data obtained by the Nobeyama 45 m radio telescope with H i and dust mass surface densities. We obtained the values of global αCO and DGR in 22 nearby spiral galaxies, with averages of 2.66 ± 1.36 M⊙ pc−2 (K km s−1)−1 and 0.0052 ± 0.0026, respectively. Furthermore, the radial variations of αCO and DGR in four barred spiral galaxies (IC 342, NGC 3627, NGC 5236, and NGC 6946) were obtained by dividing them into inner and outer regions with a boundary of 0.2 R25, where R25 is the isophotal radius at 25 mag arcsec−2 in the B band. The averages of αCO and DGR in the inner region (≤0.2 R25) are 0.36 ± 0.08 M⊙ pc−2 (K km s−1)−1 and 0.0199 ± 0.0058, while those in the outer region (>0.2 R25) are 1.49 ± 0.76 M⊙ pc−2 (K km s−1)−1 and 0.0084 ± 0.0037, respectively. The value of αCO in the outer region is 2.3 to 5.3 times larger than that of the inner region. When separated into the inner and outer regions, we find that αCO and DGR correlate with the metallicity and the star formation rate surface density. The value of αCO derived in this study tends to be smaller than those obtained in previous studies for the Milky Way and nearby star-forming galaxies. This fact can be attributed to our measurements being biased toward the inner region; we measured αCO at 0.85 and 0.76 times smaller in radius than the previous works for nearby star-forming galaxies and the Milky Way, respectively.
{"title":"CO multi-line imaging of nearby galaxies (COMING). XII. CO-to-H2 conversion factor and dust-to-gas ratio","authors":"Atsushi Yasuda, N. Kuno, K. Sorai, K. Muraoka, Y. Miyamoto, H. Kaneko, Yoshiyuki Yajima, Takahiro Tanaka, K. Morokuma-Matsui, T. Takeuchi, Masato I. N. Kobayashi","doi":"10.1093/pasj/psad034","DOIUrl":"https://doi.org/10.1093/pasj/psad034","url":null,"abstract":"\u0000 We simultaneously measured the spatially resolved CO-to-H2 conversion factor (αCO) and dust-to-gas ratio (DGR) in nearby galaxies on a kiloparsec scale. In this study, we used 12CO(J = 1–0) data obtained by the Nobeyama 45 m radio telescope with H i and dust mass surface densities. We obtained the values of global αCO and DGR in 22 nearby spiral galaxies, with averages of 2.66 ± 1.36 M⊙ pc−2 (K km s−1)−1 and 0.0052 ± 0.0026, respectively. Furthermore, the radial variations of αCO and DGR in four barred spiral galaxies (IC 342, NGC 3627, NGC 5236, and NGC 6946) were obtained by dividing them into inner and outer regions with a boundary of 0.2 R25, where R25 is the isophotal radius at 25 mag arcsec−2 in the B band. The averages of αCO and DGR in the inner region (≤0.2 R25) are 0.36 ± 0.08 M⊙ pc−2 (K km s−1)−1 and 0.0199 ± 0.0058, while those in the outer region (>0.2 R25) are 1.49 ± 0.76 M⊙ pc−2 (K km s−1)−1 and 0.0084 ± 0.0037, respectively. The value of αCO in the outer region is 2.3 to 5.3 times larger than that of the inner region. When separated into the inner and outer regions, we find that αCO and DGR correlate with the metallicity and the star formation rate surface density. The value of αCO derived in this study tends to be smaller than those obtained in previous studies for the Milky Way and nearby star-forming galaxies. This fact can be attributed to our measurements being biased toward the inner region; we measured αCO at 0.85 and 0.76 times smaller in radius than the previous works for nearby star-forming galaxies and the Milky Way, respectively.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"21 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91060642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Matekov, F. Meng, Shengbang Qian, I. Asfandiyarov, Linjia Li, S. Ehgamberdiev, Liying Zhu
We present new multi-color light curves of V1309 Her and AS CrB, which were observed by the 60 cm telescope located at the Maidanak Astronomical Observatory. Combined with the Large-Sky-Area Multi-Object Fiber Spectroscopic Telescope atmospheric parameters, we analyzed our BVRCIC light curves for both systems by employing the Wilson–Devinney program. Our results show that both systems are low-mass-ratio overcontact binaries (V1309 Her: q = 0.213, AS CrB: q = 0.16). AS CrB has a high fill-out factor, while that of V1309 Her is moderate. By adding our new times of minimum light, we found the periodic oscillations in their O − C curves, which could be explained by the light travel-time effect of the third bodies. The third lights detected during the light curve analysis support the existence of the third bodies in V1309 Her and AS CrB. Third bodies usually play an important role for the origin and evolution of the central pair by removing their angular momentum. With the angular momentum loss, a moderate-fill-out overcontact binary like V1309 Her will evolve to a deep one like AS CrB. AS CrB lies at the late evolutionary stage of contact binaries. A long-term period increase at a rate of dP/dt = 5.22(± 0.28) × 10−7 d yr−1 was detected in our O − C diagram analysis. When its orbital angular momentum is less than three times the total spin angular momentum, a system may finally evolve into a rapid-rotating single star.
{"title":"New results on the two low-mass-ratio overcontact binaries V1309 Herculis and AS Coronae Borealis","authors":"A. Matekov, F. Meng, Shengbang Qian, I. Asfandiyarov, Linjia Li, S. Ehgamberdiev, Liying Zhu","doi":"10.1093/pasj/psad030","DOIUrl":"https://doi.org/10.1093/pasj/psad030","url":null,"abstract":"\u0000 We present new multi-color light curves of V1309 Her and AS CrB, which were observed by the 60 cm telescope located at the Maidanak Astronomical Observatory. Combined with the Large-Sky-Area Multi-Object Fiber Spectroscopic Telescope atmospheric parameters, we analyzed our BVRCIC light curves for both systems by employing the Wilson–Devinney program. Our results show that both systems are low-mass-ratio overcontact binaries (V1309 Her: q = 0.213, AS CrB: q = 0.16). AS CrB has a high fill-out factor, while that of V1309 Her is moderate. By adding our new times of minimum light, we found the periodic oscillations in their O − C curves, which could be explained by the light travel-time effect of the third bodies. The third lights detected during the light curve analysis support the existence of the third bodies in V1309 Her and AS CrB. Third bodies usually play an important role for the origin and evolution of the central pair by removing their angular momentum. With the angular momentum loss, a moderate-fill-out overcontact binary like V1309 Her will evolve to a deep one like AS CrB. AS CrB lies at the late evolutionary stage of contact binaries. A long-term period increase at a rate of dP/dt = 5.22(± 0.28) × 10−7 d yr−1 was detected in our O − C diagram analysis. When its orbital angular momentum is less than three times the total spin angular momentum, a system may finally evolve into a rapid-rotating single star.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"55 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80195233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar activities directly or indirectly affect space missions, geophysical environment, space climate, and human activities. We used the long short-term memory (LSTM) deep learning method to predict the amplitude and peak time of solar cycles (SCs) 25 and 26 by using the monthly relative sunspot number data taken from the National Astronomical Observatory of Japan (NAOJ). The dataset is divided into eight schemes of two to nine slices for training, showing that the five-slice LSTM model with root mean square error of 11.38 is the optimal model. According to the prediction, SC 25 will be about 21$%$ stronger than SC 24, with a peak of 135.2 occurring in 2024 April. SC 26 will be similar to SC 25 and reach its peak of 135.0 in 2035 January. Our analysis results indicate that the sunspot data from NAOJ is highly credible and comparable.
{"title":"Predicting the 25th and 26th solar cycles using the long short-term memory method","authors":"Xiaohuan Liu, S. Zeng, L. Deng, X. Zeng, S. Zheng","doi":"10.1093/pasj/psad029","DOIUrl":"https://doi.org/10.1093/pasj/psad029","url":null,"abstract":"\u0000 Solar activities directly or indirectly affect space missions, geophysical environment, space climate, and human activities. We used the long short-term memory (LSTM) deep learning method to predict the amplitude and peak time of solar cycles (SCs) 25 and 26 by using the monthly relative sunspot number data taken from the National Astronomical Observatory of Japan (NAOJ). The dataset is divided into eight schemes of two to nine slices for training, showing that the five-slice LSTM model with root mean square error of 11.38 is the optimal model. According to the prediction, SC 25 will be about 21$%$ stronger than SC 24, with a peak of 135.2 occurring in 2024 April. SC 26 will be similar to SC 25 and reach its peak of 135.0 in 2035 January. Our analysis results indicate that the sunspot data from NAOJ is highly credible and comparable.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"69 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84849849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Kagetani, N. Narita, T. Kimura, T. Hirano, M. Ikoma, H. Ishikawa, S. Giacalone, A. Fukui, T. Kodama, Rebecca Gore, A. Schroeder, Y. Hori, K. Kawauchi, N. Watanabe, M. Mori, Y. Zou, K. Ikuta, V. Krishnamurthy, Jon K. Zink, K. Hardegree-Ullman, H. Harakawa, T. Kudo, T. Kotani, T. Kurokawa, N. Kusakabe, M. Kuzuhara, J. D. de Leon, J. Livingston, J. Nishikawa, M. Omiya, E. Pallé, H. Parviainen, T. Serizawa, H. Teng, A. Ueda, Motohide Tamura
We report on the determination of the mass of TOI-519 b, a transiting substellar object around a mid-M dwarf. We carried out radial velocity measurements using Subaru/InfraRed Doppler (IRD), revealing that TOI-519 b is a planet with a mass of $0.463^{+0.082}_{-0.088}, M_{rm Jup}$. We also found that the host star is metal rich ([Fe/H] = 0.27 ± 0.09 dex) and has the lowest effective temperature (Teff = 3322 ± 49 K) among all stars hosting known close-in giant planets based on the IRD spectra and mid-resolution infrared spectra obtained with NASA Infrared Telescope Facility/SpeX. The core mass of TOI-519 b inferred from a thermal evolution model ranges from 0 to ∼30 M⊕, which can be explained by both core accretion and disk instability models as the formation origins of this planet. However, TOI-519 is in line with the emerging trend that M dwarfs with close-in giant planets tend to have high metallicity, which may indicate that they formed in the core accretion model. The system is also consistent with the potential trend that close-in giant planets around M dwarfs tend to be less massive than those around FGK dwarfs.
{"title":"The mass of TOI-519 b: A close-in giant planet transiting a metal-rich mid-M dwarf","authors":"T. Kagetani, N. Narita, T. Kimura, T. Hirano, M. Ikoma, H. Ishikawa, S. Giacalone, A. Fukui, T. Kodama, Rebecca Gore, A. Schroeder, Y. Hori, K. Kawauchi, N. Watanabe, M. Mori, Y. Zou, K. Ikuta, V. Krishnamurthy, Jon K. Zink, K. Hardegree-Ullman, H. Harakawa, T. Kudo, T. Kotani, T. Kurokawa, N. Kusakabe, M. Kuzuhara, J. D. de Leon, J. Livingston, J. Nishikawa, M. Omiya, E. Pallé, H. Parviainen, T. Serizawa, H. Teng, A. Ueda, Motohide Tamura","doi":"10.1093/pasj/psad031","DOIUrl":"https://doi.org/10.1093/pasj/psad031","url":null,"abstract":"\u0000 We report on the determination of the mass of TOI-519 b, a transiting substellar object around a mid-M dwarf. We carried out radial velocity measurements using Subaru/InfraRed Doppler (IRD), revealing that TOI-519 b is a planet with a mass of $0.463^{+0.082}_{-0.088}, M_{rm Jup}$. We also found that the host star is metal rich ([Fe/H] = 0.27 ± 0.09 dex) and has the lowest effective temperature (Teff = 3322 ± 49 K) among all stars hosting known close-in giant planets based on the IRD spectra and mid-resolution infrared spectra obtained with NASA Infrared Telescope Facility/SpeX. The core mass of TOI-519 b inferred from a thermal evolution model ranges from 0 to ∼30 M⊕, which can be explained by both core accretion and disk instability models as the formation origins of this planet. However, TOI-519 is in line with the emerging trend that M dwarfs with close-in giant planets tend to have high metallicity, which may indicate that they formed in the core accretion model. The system is also consistent with the potential trend that close-in giant planets around M dwarfs tend to be less massive than those around FGK dwarfs.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":"37 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80107152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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