The grand minimum in the Sun's activity is a distinctive mode characterized by a magnetic lull that almost completely lacks the emergence of sunspots on the solar surface for an extended duration. The factors driving this transition of an otherwise magnetically active star into a quiescent phase, the processes occurring within the solar interior and across the heliosphere during this period, and the mechanisms leading to the eventual resurgence of surface magnetic activity remain enigmatic. However, there have been sustained efforts in the past few decades to unravel these mysteries by employing a combination of observation, reconstruction and simulation of solar magnetic variability. Here, we summarize recent research on the solar grand minimum and highlight some outstanding challenges - both intellectual and practical - that necessitate further investigations.
{"title":"Understanding Grand Minima in Solar Activity: Confronting Observations with Dynamo Simulations","authors":"Chitradeep Saha, Dibyendu Nandy","doi":"arxiv-2409.09775","DOIUrl":"https://doi.org/arxiv-2409.09775","url":null,"abstract":"The grand minimum in the Sun's activity is a distinctive mode characterized\u0000by a magnetic lull that almost completely lacks the emergence of sunspots on\u0000the solar surface for an extended duration. The factors driving this transition\u0000of an otherwise magnetically active star into a quiescent phase, the processes\u0000occurring within the solar interior and across the heliosphere during this\u0000period, and the mechanisms leading to the eventual resurgence of surface\u0000magnetic activity remain enigmatic. However, there have been sustained efforts\u0000in the past few decades to unravel these mysteries by employing a combination\u0000of observation, reconstruction and simulation of solar magnetic variability.\u0000Here, we summarize recent research on the solar grand minimum and highlight\u0000some outstanding challenges - both intellectual and practical - that\u0000necessitate further investigations.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Linfeng Chang, Shengbang Qian, Lei Zang, Fuxing Li
The detection of O- and B-type stars with extremely low-mass companions is very important for understanding the formation and evolution of binary stars. However, their finding remains a challenge because the low-mass components in such systems contribute such small flux to the total. During the searching for pulsations among O- and B-type stars by using the TESS data, we found two short-period and B-type (B9) eclipsing binaries with orbital periods of 1.61613 and 2.37857 days. Photometric solutions of the two close binaries were derived by analyzing the TESS light curves with the W-D method. It is discovered that both of them are detached binaries with extremely low mass ratios of 0.067(2) for TIC 260342097 and 0.140(3) for TIC 209148631, respectively. The determined mass ratio indicates that TIC 260342097 is one of the lowest mass ratios among known B-type binary systems. We showed that the two systems have total eclipses with a broad and flat secondary minimum, suggesting that the photometric parameters could be derived reliably. The absolute parameters of the two binaries are estimated and it is found that the secondary components in the two systems are over-luminous and over-size when compared with the normal low-mass and cool main-sequence (MS) stars. These findings may imply that the two systems are composed of a B-type MS primary and a cool pre-MS secondary with orbital periods shorter than 2.5 days. They are valuable targets to test theories of binary star formation and evolution.
{"title":"Detection of two totally eclipsing B-type binaries with extremely low mass ratios","authors":"Linfeng Chang, Shengbang Qian, Lei Zang, Fuxing Li","doi":"arxiv-2409.09246","DOIUrl":"https://doi.org/arxiv-2409.09246","url":null,"abstract":"The detection of O- and B-type stars with extremely low-mass companions is\u0000very important for understanding the formation and evolution of binary stars.\u0000However, their finding remains a challenge because the low-mass components in\u0000such systems contribute such small flux to the total. During the searching for\u0000pulsations among O- and B-type stars by using the TESS data, we found two\u0000short-period and B-type (B9) eclipsing binaries with orbital periods of 1.61613\u0000and 2.37857 days. Photometric solutions of the two close binaries were derived\u0000by analyzing the TESS light curves with the W-D method. It is discovered that\u0000both of them are detached binaries with extremely low mass ratios of 0.067(2)\u0000for TIC 260342097 and 0.140(3) for TIC 209148631, respectively. The determined\u0000mass ratio indicates that TIC 260342097 is one of the lowest mass ratios among\u0000known B-type binary systems. We showed that the two systems have total eclipses\u0000with a broad and flat secondary minimum, suggesting that the photometric\u0000parameters could be derived reliably. The absolute parameters of the two\u0000binaries are estimated and it is found that the secondary components in the two\u0000systems are over-luminous and over-size when compared with the normal low-mass\u0000and cool main-sequence (MS) stars. These findings may imply that the two\u0000systems are composed of a B-type MS primary and a cool pre-MS secondary with\u0000orbital periods shorter than 2.5 days. They are valuable targets to test\u0000theories of binary star formation and evolution.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Bourdarot, F. Eisenhauer, S. Yazıcı, H. Feuchtgruber, J-B Le Bouquin, M. Hartl, C. Rau, J. Graf, N. More, E. Wieprecht, F. Haussmann, F. Widmann, D. Lutz, R. Genzel, F. Gonte, S. Oberti, J. Kolb, J. Woillez, H. Bonnet, D. Schuppe, A. Brara, J. Hartwig, A. Goldbrunner, C. Furchtsam, F. Soller, S. Czempiel, J. Eibl, D. Huber, S. Uysal, I. Treffler, H. Ozdemir, V. Gopinatha, P. Bourget, A. Berdeu, S. Gillessen, T. Ott, P. Berio, O. Boebion, F. Millour, R. Dembet, C. Edouard, T. Gomes, T. Shimizu, A. Drescher, M. Fabricius, J. Shangguan, S. Lagarde, S. Robbe-Dubois, F. Allouche, H. Nowacki, D. Defrere, P. J. V. Garcia, S. Hoenig, L. Kreidbergg, T. Paumard, C. Straubmeier
We present the Wavefront Sensor units of the Gravity Plus Adaptive Optics (GPAO) system, which will equip all 8m class telescopes of the VLTI and is an instrumental part of the GRAVITY+ project. It includes two modules for each Wavefront Sensor unit: a Natural Guide Star sensor with high-order 40x40 Shack-Hartmann and a Laser Guide Star 30x30 sensor. The state-of-the-art AO correction will considerably improve the performance for interferometry, in particular high-contrast observations for NGS observations and all-sky coverage with LGS, which will be implemented for the first time on VLTI instruments. In the following, we give an overview of the Wavefront Sensor units system after completion of their integration and characterization.
{"title":"GRAVITY+ Wavefront Sensors: High-Contrast, Laser Guide Star, Adaptive Optics systems for the VLTI","authors":"G. Bourdarot, F. Eisenhauer, S. Yazıcı, H. Feuchtgruber, J-B Le Bouquin, M. Hartl, C. Rau, J. Graf, N. More, E. Wieprecht, F. Haussmann, F. Widmann, D. Lutz, R. Genzel, F. Gonte, S. Oberti, J. Kolb, J. Woillez, H. Bonnet, D. Schuppe, A. Brara, J. Hartwig, A. Goldbrunner, C. Furchtsam, F. Soller, S. Czempiel, J. Eibl, D. Huber, S. Uysal, I. Treffler, H. Ozdemir, V. Gopinatha, P. Bourget, A. Berdeu, S. Gillessen, T. Ott, P. Berio, O. Boebion, F. Millour, R. Dembet, C. Edouard, T. Gomes, T. Shimizu, A. Drescher, M. Fabricius, J. Shangguan, S. Lagarde, S. Robbe-Dubois, F. Allouche, H. Nowacki, D. Defrere, P. J. V. Garcia, S. Hoenig, L. Kreidbergg, T. Paumard, C. Straubmeier","doi":"arxiv-2409.08438","DOIUrl":"https://doi.org/arxiv-2409.08438","url":null,"abstract":"We present the Wavefront Sensor units of the Gravity Plus Adaptive Optics\u0000(GPAO) system, which will equip all 8m class telescopes of the VLTI and is an\u0000instrumental part of the GRAVITY+ project. It includes two modules for each\u0000Wavefront Sensor unit: a Natural Guide Star sensor with high-order 40x40\u0000Shack-Hartmann and a Laser Guide Star 30x30 sensor. The state-of-the-art AO\u0000correction will considerably improve the performance for interferometry, in\u0000particular high-contrast observations for NGS observations and all-sky coverage\u0000with LGS, which will be implemented for the first time on VLTI instruments. In\u0000the following, we give an overview of the Wavefront Sensor units system after\u0000completion of their integration and characterization.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francesco Gabrielli, Lumen Boco, Giancarlo Ghirlanda, Om Sharan Salafia, Ruben Salvaterra, Mario Spera, Andrea Lapi
The stellar initial-mass function (IMF) represents a fundamental quantity in astrophysics and cosmology, describing the mass distribution of stars from low to very-high masses. It is intimately linked to a wide variety of topics, including stellar and binary evolution, galaxy evolution, chemical enrichment, and cosmological reionization. Nonetheless, the IMF still remains highly uncertain. In this work, we aim at determining the IMF with a novel approach based on the observed rates of transients of stellar origin. We parametrize the IMF with a simple, but flexible, Larson shape, and insert it into a parametric model for the cosmic UV luminosity density, local stellar mass density, type Ia supernova (SN Ia), core-collapse supernova (CCSN), and long gamma-ray burst (LGRB) rates as function of redshift. We constrain our free parameters by matching the model predictions to a set of empirical determinations for the corresponding quantities, via a Bayesian Markov-Chain Monte Carlo method. Remarkably, we are able to provide an independent IMF determination, with characteristic mass $m_c=0.10^{+0.24}_{-0.08}:M_{odot}$, and high-mass slope $xi=-2.53^{+0.24}_{-0.27}$, that is in accordance with the widely-used IMF parameterizations (e.g. Salpeter, Kroupa, Chabrier). Moreover, the adoption of an up-to-date recipe for the cosmic metallicity evolution, allows us to constrain the maximum metallicity of LGRB progenitors to $Z_{max}=0.12^{+0.29}_{-0.05}:Z_{odot}$. We also find what progenitor fraction actually leads to SN Ia or LGRB emission, put constraints on the CCSN and LGRB progenitor mass ranges, and test the IMF universality. These results show the potential of this kind of approach for studying the IMF, its putative evolution with galactic environment and cosmic history, and the properties of SN Ia, CCSN and LGRB progenitors, especially considering the wealth of data incoming in the future.
{"title":"Constraining the Initial-Mass Function via Stellar Transients","authors":"Francesco Gabrielli, Lumen Boco, Giancarlo Ghirlanda, Om Sharan Salafia, Ruben Salvaterra, Mario Spera, Andrea Lapi","doi":"arxiv-2409.09118","DOIUrl":"https://doi.org/arxiv-2409.09118","url":null,"abstract":"The stellar initial-mass function (IMF) represents a fundamental quantity in\u0000astrophysics and cosmology, describing the mass distribution of stars from low\u0000to very-high masses. It is intimately linked to a wide variety of topics,\u0000including stellar and binary evolution, galaxy evolution, chemical enrichment,\u0000and cosmological reionization. Nonetheless, the IMF still remains highly\u0000uncertain. In this work, we aim at determining the IMF with a novel approach\u0000based on the observed rates of transients of stellar origin. We parametrize the\u0000IMF with a simple, but flexible, Larson shape, and insert it into a parametric\u0000model for the cosmic UV luminosity density, local stellar mass density, type Ia\u0000supernova (SN Ia), core-collapse supernova (CCSN), and long gamma-ray burst\u0000(LGRB) rates as function of redshift. We constrain our free parameters by\u0000matching the model predictions to a set of empirical determinations for the\u0000corresponding quantities, via a Bayesian Markov-Chain Monte Carlo method.\u0000Remarkably, we are able to provide an independent IMF determination, with\u0000characteristic mass $m_c=0.10^{+0.24}_{-0.08}:M_{odot}$, and high-mass slope\u0000$xi=-2.53^{+0.24}_{-0.27}$, that is in accordance with the widely-used IMF\u0000parameterizations (e.g. Salpeter, Kroupa, Chabrier). Moreover, the adoption of\u0000an up-to-date recipe for the cosmic metallicity evolution, allows us to\u0000constrain the maximum metallicity of LGRB progenitors to\u0000$Z_{max}=0.12^{+0.29}_{-0.05}:Z_{odot}$. We also find what progenitor\u0000fraction actually leads to SN Ia or LGRB emission, put constraints on the CCSN\u0000and LGRB progenitor mass ranges, and test the IMF universality. These results\u0000show the potential of this kind of approach for studying the IMF, its putative\u0000evolution with galactic environment and cosmic history, and the properties of\u0000SN Ia, CCSN and LGRB progenitors, especially considering the wealth of data\u0000incoming in the future.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gode Angloher, Mukund Bharadwaj, Mariano Cababie, Ivan Colantoni, Ioan Dafinei, Alessio Ludovico De Santis, Natalia Di Marco, Leonie Einfalt, Francesco Ferella, Fernando Ferroni, Stephan Fichtinger, Adriano Filipponi, Torsten Frank, Markus Friedl, Zengwei Ge, Matti Heikinheimo, Maximilian Hughes, Katri Huitu, Moritz Kellermann, Rituparna Maji, Michele Mancuso, Lorenzo Pagnanini, Federica Petricca, Stefano Pirro, Franz Pröbst, Gianni Profeta, Andrei Puiu, Florian Reindl, Karoline Schäffner, Jochen Schieck, Philipp Schreiner, Christoph Schwertner, Kumrie Shera, Martin Stahlberg, Alex Stendhal, Matthew Stukel, Cesare Tresca, Felix Wagner, Shihai Yue, Vanessa Zema, Yong Zhu
While neutrinos are often treated as a background for many dark matter experiments, these particles offer a new avenue for physics: the detection of core-collapse supernovae. Supernovae are extremely energetic, violent and complex events that mark the death of massive stars. During their collapse stars emit a large number of neutrinos in a short burst. These neutrinos carry 99% of the emitted energy which makes their detection fundamental in understanding supernovae. This paper illustrates how COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches), a sodium iodide (NaI) based dark matter search, will be sensitive to the next galactic core-collapse supernova. The experiment is composed of two separate detectors which will be sensitive to far and nearby supernovae. The inner core of the experiment will consist of NaI crystals operating as scintillating calorimeters, mainly sensitive to the Coherent Elastic Scattering of Neutrinos (CE$nu$NS) against the Na and I nuclei. The low mass of the cryogenic detectors gives the experiment a sensitivity to close supernovae below 1kpc without pileup. They will see up to hundreds of CE$nu$NS events from a supernova happening at 200pc. The crystals reside at the center of a cylindrical 230T water tank, instrumented with 30 photomultipliers. This tank acts as a passive and active shield able to detect the Cherenkov radiation induced by impinging charged particles from ambient and cosmogenic radioactivity. A supernova near the Milky Way Center (10kpc) will be easily detected inducing $sim$60 measurable events, and the water tank will have a 3$sigma$ sensitivity to supernovae up to 22kpc, seeing $sim$10 events. This paper shows how, even without dedicated optimization, modern dark matter experiments will also play their part in the multi-messenger effort to detect the next galactic core-collapse supernova.
虽然中微子通常被视为许多暗物质实验的背景，但这些粒子为物理学提供了一个新的途径：探测核坍缩超新星。超新星是标志着大质量恒星死亡的极度高能、剧烈和复杂的事件。在其坍缩过程中，恒星会在短时间内释放出大量中微子。这些中微子携带了99%的发射能量，这使得探测它们成为了解超新星的基础。本文阐述了基于碘化钠（NaI）的暗物质搜索--COSINUS（下一代地下搜索所见中微子低温观测站）将如何对下一个星系的核心坍缩超新星保持敏感。该实验由两个分离的探测器组成，分别对远处和近处的超新星敏感。实验的内核将由作为闪烁量热计工作的 NaI 晶体组成，主要对中微子对 Na 核和 I 核的相干弹性散射（CE$nu$NS）敏感。低温探测器的低质量使实验对低于 1kpc 的近距离超新星具有灵敏度，而不会产生堆积。它们将看到来自发生在200pc的超新星的多达数百个CE$nu$NS事件。晶体位于 230T 圆柱形水箱的中心，上面装有 30 个光电倍增管。这个水箱就像一个被动和主动的屏蔽，能够探测到由环境和宇宙放射性带电粒子撞击引起的切伦科夫辐射。银河系中心（10kpc）附近的超新星将很容易被探测到，从而诱发60个可测量事件，而水箱对高达22kpc的超新星的灵敏度为3个西格玛，能看到10个事件。本文展示了即使没有专门的优化，现代暗物质实验也将如何在探测下一颗银河系核心坍缩超新星的多信使努力中发挥作用。
{"title":"Neutrino flux sensitivity to the next galactic core-collapse supernova in COSINUS","authors":"Gode Angloher, Mukund Bharadwaj, Mariano Cababie, Ivan Colantoni, Ioan Dafinei, Alessio Ludovico De Santis, Natalia Di Marco, Leonie Einfalt, Francesco Ferella, Fernando Ferroni, Stephan Fichtinger, Adriano Filipponi, Torsten Frank, Markus Friedl, Zengwei Ge, Matti Heikinheimo, Maximilian Hughes, Katri Huitu, Moritz Kellermann, Rituparna Maji, Michele Mancuso, Lorenzo Pagnanini, Federica Petricca, Stefano Pirro, Franz Pröbst, Gianni Profeta, Andrei Puiu, Florian Reindl, Karoline Schäffner, Jochen Schieck, Philipp Schreiner, Christoph Schwertner, Kumrie Shera, Martin Stahlberg, Alex Stendhal, Matthew Stukel, Cesare Tresca, Felix Wagner, Shihai Yue, Vanessa Zema, Yong Zhu","doi":"arxiv-2409.09109","DOIUrl":"https://doi.org/arxiv-2409.09109","url":null,"abstract":"While neutrinos are often treated as a background for many dark matter\u0000experiments, these particles offer a new avenue for physics: the detection of\u0000core-collapse supernovae. Supernovae are extremely energetic, violent and\u0000complex events that mark the death of massive stars. During their collapse\u0000stars emit a large number of neutrinos in a short burst. These neutrinos carry\u000099% of the emitted energy which makes their detection fundamental in\u0000understanding supernovae. This paper illustrates how COSINUS (Cryogenic\u0000Observatory for SIgnatures seen in Next-generation Underground Searches), a\u0000sodium iodide (NaI) based dark matter search, will be sensitive to the next\u0000galactic core-collapse supernova. The experiment is composed of two separate\u0000detectors which will be sensitive to far and nearby supernovae. The inner core\u0000of the experiment will consist of NaI crystals operating as scintillating\u0000calorimeters, mainly sensitive to the Coherent Elastic Scattering of Neutrinos\u0000(CE$nu$NS) against the Na and I nuclei. The low mass of the cryogenic\u0000detectors gives the experiment a sensitivity to close supernovae below 1kpc\u0000without pileup. They will see up to hundreds of CE$nu$NS events from a\u0000supernova happening at 200pc. The crystals reside at the center of a\u0000cylindrical 230T water tank, instrumented with 30 photomultipliers. This tank\u0000acts as a passive and active shield able to detect the Cherenkov radiation\u0000induced by impinging charged particles from ambient and cosmogenic\u0000radioactivity. A supernova near the Milky Way Center (10kpc) will be easily\u0000detected inducing $sim$60 measurable events, and the water tank will have a\u00003$sigma$ sensitivity to supernovae up to 22kpc, seeing $sim$10 events. This\u0000paper shows how, even without dedicated optimization, modern dark matter\u0000experiments will also play their part in the multi-messenger effort to detect\u0000the next galactic core-collapse supernova.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deep and low mass-ratio contact binaries (DLMCBs) are believed to be in the final stage of their contact phase, potentially leading to the formation of fast-rotating single stars such as FK Com-type stars and blue stragglers, as well as luminous red novae. These systems serve as an excellent laboratory for studying stellar coalescence and merging processes. Our search for DLMCBs began in 2004 and has since identified a group of such systems. Together with that collected from the literature, more than 100 DLMCBs have been detected so far. Half of them have had their periods investigated based on O-C curves. Some have shown period increases, while others have exhibited period decreases. Among them, more than half DLMCBs have cyclic variations, suggesting the possibility of the existence of a third body orbiting around the DLMCBs. Furthermore, with more data obtained extending the span of the O-C curve, more cyclic variations could be detected. The high proportion of signs of the presence of third bodies makes them an essential factor to consider when studying the merger of contact binaries.
{"title":"Deep and low mass-ratio contact binaries and their third bodies","authors":"Liying Zhu, Shengbang Qian, Wenping Liao, Jia Zhang, Xiangdong Shi, Linjia Li, Fangbin Meng, Jiangjiao Wang, Azizbek Matekov","doi":"arxiv-2409.08499","DOIUrl":"https://doi.org/arxiv-2409.08499","url":null,"abstract":"Deep and low mass-ratio contact binaries (DLMCBs) are believed to be in the\u0000final stage of their contact phase, potentially leading to the formation of\u0000fast-rotating single stars such as FK Com-type stars and blue stragglers, as\u0000well as luminous red novae. These systems serve as an excellent laboratory for\u0000studying stellar coalescence and merging processes. Our search for DLMCBs began\u0000in 2004 and has since identified a group of such systems. Together with that\u0000collected from the literature, more than 100 DLMCBs have been detected so far.\u0000Half of them have had their periods investigated based on O-C curves. Some have\u0000shown period increases, while others have exhibited period decreases. Among\u0000them, more than half DLMCBs have cyclic variations, suggesting the possibility\u0000of the existence of a third body orbiting around the DLMCBs. Furthermore, with\u0000more data obtained extending the span of the O-C curve, more cyclic variations\u0000could be detected. The high proportion of signs of the presence of third bodies\u0000makes them an essential factor to consider when studying the merger of contact\u0000binaries.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"98 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sergio Sánchez-Sanjuán, Jesús Hernández, Ángeles Pérez-Villegas, Carlos Román-Zúñiga, Luis Aguilar, Javier Ballesteros-Paredes, Andrea Bonilla-Barroso
In this work, we analysed young stellar clusters with spatial and kinematic coherence in the Orion star-forming complex. For this study, we selected a sample of pre-main sequence candidates using parallaxes, proper motions and positions on the colour-magnitude diagram. After applying a hierarchical clustering algorithm in the 5D parameter space provided by Gaia DR3, we divided the recovered clusters into two regimes: Big Structures and Small Structures, defined by the number of detected stars per cluster. In the first regime, we found 13 stellar groups distributed along the declination axis in the regions where there is a high density of stars. In the second regime, we recovered 34 clusters classified into two types: 14 as small groups completely independent from the larger structures, including four candidates of new clusters, and 12 classified as sub-structures embedded within five larger clusters. Additionally, radial velocity data from APOGEE-2 and GALAH DR3 was included to study the phase space in some regions of the Orion complex. From the Big Structure regime, we found evidence of a general expansion in the Orion OB1 association over a common centre, giving a clue about the dynamical effects the region is undergoing. Likewise, in the Small Structure regime, the projected kinematics shows the ballistic expansion in the $lambda$ Orionis association and the detection of likely events of clusters' close encounters in the OB1 association.
{"title":"Kinematic study of the Orion Complex: Analysing the young stellar clusters from big and small structures","authors":"Sergio Sánchez-Sanjuán, Jesús Hernández, Ángeles Pérez-Villegas, Carlos Román-Zúñiga, Luis Aguilar, Javier Ballesteros-Paredes, Andrea Bonilla-Barroso","doi":"arxiv-2409.09206","DOIUrl":"https://doi.org/arxiv-2409.09206","url":null,"abstract":"In this work, we analysed young stellar clusters with spatial and kinematic\u0000coherence in the Orion star-forming complex. For this study, we selected a\u0000sample of pre-main sequence candidates using parallaxes, proper motions and\u0000positions on the colour-magnitude diagram. After applying a hierarchical\u0000clustering algorithm in the 5D parameter space provided by Gaia DR3, we divided\u0000the recovered clusters into two regimes: Big Structures and Small Structures,\u0000defined by the number of detected stars per cluster. In the first regime, we\u0000found 13 stellar groups distributed along the declination axis in the regions\u0000where there is a high density of stars. In the second regime, we recovered 34\u0000clusters classified into two types: 14 as small groups completely independent\u0000from the larger structures, including four candidates of new clusters, and 12\u0000classified as sub-structures embedded within five larger clusters.\u0000Additionally, radial velocity data from APOGEE-2 and GALAH DR3 was included to\u0000study the phase space in some regions of the Orion complex. From the Big\u0000Structure regime, we found evidence of a general expansion in the Orion OB1\u0000association over a common centre, giving a clue about the dynamical effects the\u0000region is undergoing. Likewise, in the Small Structure regime, the projected\u0000kinematics shows the ballistic expansion in the $lambda$ Orionis association\u0000and the detection of likely events of clusters' close encounters in the OB1\u0000association.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Casey L. Brinkman, Alex S. Polanski, Daniel Huber, Lauren M. Weiss, Diana Valencia, Mykhaylo Plotnykov
Planets and the stars they orbit are born from the same cloud of gas and dust, and the primordial compositions of rocky exoplanets have been assumed to have iron and refractory abundance ratios consistent with their host star. To test this assumption, we modeled the interior iron-to-rock ratio of 20 super-Earth sized (1-1.8R$_{oplus}$) exoplanets around stars with homogeneously measured stellar parameters. We computed the core mass fraction for each planet and an equivalent ``core mass fraction'' for each host star based on its Fe and Mg abundances. We then fit a linear correlation using two methods (Ordinary Least Squares and Orthogonal Distance Regression) between planetary and stellar core mass fraction, obtaining substantially different slopes between these two methods (m=1.3 $pm$ 1.0 and m=5.6 $pm$ 1.6, respectively). Additionally, we find that 75$%$ of planets have a core mass fraction consistent with their host star to within 1$sigma$, and do not identify a distinct population of high-density super-Mercuries. Overall, we conclude that current uncertainties in observational data and differences in modeling methods prevent definitive conclusions about the relationship between between planet and host star chemical compositions.
{"title":"Revisiting the Relationship Between Rocky Exoplanet and Stellar Compositions: Reduced Evidence for a Super-Mercury Population","authors":"Casey L. Brinkman, Alex S. Polanski, Daniel Huber, Lauren M. Weiss, Diana Valencia, Mykhaylo Plotnykov","doi":"arxiv-2409.08361","DOIUrl":"https://doi.org/arxiv-2409.08361","url":null,"abstract":"Planets and the stars they orbit are born from the same cloud of gas and\u0000dust, and the primordial compositions of rocky exoplanets have been assumed to\u0000have iron and refractory abundance ratios consistent with their host star. To\u0000test this assumption, we modeled the interior iron-to-rock ratio of 20\u0000super-Earth sized (1-1.8R$_{oplus}$) exoplanets around stars with\u0000homogeneously measured stellar parameters. We computed the core mass fraction\u0000for each planet and an equivalent ``core mass fraction'' for each host star\u0000based on its Fe and Mg abundances. We then fit a linear correlation using two\u0000methods (Ordinary Least Squares and Orthogonal Distance Regression) between\u0000planetary and stellar core mass fraction, obtaining substantially different\u0000slopes between these two methods (m=1.3 $pm$ 1.0 and m=5.6 $pm$ 1.6,\u0000respectively). Additionally, we find that 75$%$ of planets have a core mass\u0000fraction consistent with their host star to within 1$sigma$, and do not\u0000identify a distinct population of high-density super-Mercuries. Overall, we\u0000conclude that current uncertainties in observational data and differences in\u0000modeling methods prevent definitive conclusions about the relationship between\u0000between planet and host star chemical compositions.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna Lueber, Kevin Heng, Brendan P. Bowler, Daniel Kitzmann, Johanna M. Vos, Yifan Zhou
Motivated by the observed ~30% variations in flux from the L7 dwarf VHS 1256 b, we subjected its time-resolved Hubble Space Telescope (HST) WFC3 spectra (measured in two epochs in 2018 and 2020), as well as medium-resolution Very Large Telescope (VLT) X-shooter and Early Release Science James Webb Space Telescope (JWST) spectra to a suite of both standard Bayesian (nested sampling) and machine-learning (random forest) retrievals. We find that both HST and VLT data require vertically varying abundance profiles of water in order to model the spectra accurately. Despite the large flux variations observed in the HST data, the temporal variability cannot be attributed to a single varying atmospheric property. The retrieved atmospheric quantities are consistent with being invariant across time. However, we find that model grids provide generally poor fits to the measured HST spectra and are unsuitable for quantifying the temporal variability of atmospheric properties. Additionally, our analysis of JWST spectra using model grids indicates consistency in retrieved properties across different wavelength channels. Despite the temporal variability in flux, the retrieved properties between HST and VLT, as well as between HST and JWST, are consistent within the respective posterior uncertainties. Such an outcome bodes well for future retrieval analyses of exoplanetary atmospheres, which are expected to exhibit weaker flux variations.
{"title":"The Retrieved Atmospheric Properties of the Sub-stellar Object VHS 1256 b from Analyzing HST, VLT and JWST Spectra","authors":"Anna Lueber, Kevin Heng, Brendan P. Bowler, Daniel Kitzmann, Johanna M. Vos, Yifan Zhou","doi":"arxiv-2409.08254","DOIUrl":"https://doi.org/arxiv-2409.08254","url":null,"abstract":"Motivated by the observed ~30% variations in flux from the L7 dwarf VHS 1256\u0000b, we subjected its time-resolved Hubble Space Telescope (HST) WFC3 spectra\u0000(measured in two epochs in 2018 and 2020), as well as medium-resolution Very\u0000Large Telescope (VLT) X-shooter and Early Release Science James Webb Space\u0000Telescope (JWST) spectra to a suite of both standard Bayesian (nested sampling)\u0000and machine-learning (random forest) retrievals. We find that both HST and VLT\u0000data require vertically varying abundance profiles of water in order to model\u0000the spectra accurately. Despite the large flux variations observed in the HST\u0000data, the temporal variability cannot be attributed to a single varying\u0000atmospheric property. The retrieved atmospheric quantities are consistent with\u0000being invariant across time. However, we find that model grids provide\u0000generally poor fits to the measured HST spectra and are unsuitable for\u0000quantifying the temporal variability of atmospheric properties. Additionally,\u0000our analysis of JWST spectra using model grids indicates consistency in\u0000retrieved properties across different wavelength channels. Despite the temporal\u0000variability in flux, the retrieved properties between HST and VLT, as well as\u0000between HST and JWST, are consistent within the respective posterior\u0000uncertainties. Such an outcome bodes well for future retrieval analyses of\u0000exoplanetary atmospheres, which are expected to exhibit weaker flux variations.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fan Yang, Richard J. Long, Eamonn Kerins, Supachai Awiphan, Su-Su Shan, Bo Zhang, Yogesh C. Joshi, Napaporn A-thano, Ing-Guey Jiang, Akshay Priyadarshi, Ji-Feng Liu
Hot Jupiters should initially form at considerable distances from host stars and subsequently migrate towards inner regions, supported directly by transit timing variation (TTV). We report the TTV of K2-237b, using reproduced timings fitted from textit{Kepler} K2 and textit{TESS} data. The timings span from 2016 to 2021, leading to an observational baseline of 5 years. The timing evolution presents a significant bias to a constant period scenario. The model evidence is evaluated utilizing the Bayesian Information Criterion (BIC), which favours the scenario of period decay with a $Delta$BIC of 14.1. The detected TTV induces a period decay rate ($dot{P}$) of -1.14$pm$0.28$times$10$^{-8}$ days per day ($-$0.36 s/year). Fitting the spectral energy distribution, we find infrared excess at the significance level of 1.5 $sigma$ for WISE W1 and W2 bands, and 2 $sigma$ level for W3 and W4 bands. This potentially reveals the existence of a stellar disk, consisting of hot dust at 800$pm$300 K, showing a $L_{dust}/L_{ast}$ of 5$pm$3$times$10$^{-3}$. We obtain a stellar age of 1.0$^{+1.4}_{-0.7}$$times$10$^{9}$ yr from isochrone fitting. The properties of K2-237b potentially serve as a direct observational support to the planet disk migration though more observation are needed.
{"title":"Transit Timing Variation of K2-237b: Hints Toward Planet Disk Migration","authors":"Fan Yang, Richard J. Long, Eamonn Kerins, Supachai Awiphan, Su-Su Shan, Bo Zhang, Yogesh C. Joshi, Napaporn A-thano, Ing-Guey Jiang, Akshay Priyadarshi, Ji-Feng Liu","doi":"arxiv-2409.07865","DOIUrl":"https://doi.org/arxiv-2409.07865","url":null,"abstract":"Hot Jupiters should initially form at considerable distances from host stars\u0000and subsequently migrate towards inner regions, supported directly by transit\u0000timing variation (TTV). We report the TTV of K2-237b, using reproduced timings\u0000fitted from textit{Kepler} K2 and textit{TESS} data. The timings span from\u00002016 to 2021, leading to an observational baseline of 5 years. The timing\u0000evolution presents a significant bias to a constant period scenario. The model\u0000evidence is evaluated utilizing the Bayesian Information Criterion (BIC), which\u0000favours the scenario of period decay with a $Delta$BIC of 14.1. The detected\u0000TTV induces a period decay rate ($dot{P}$) of -1.14$pm$0.28$times$10$^{-8}$\u0000days per day ($-$0.36 s/year). Fitting the spectral energy distribution, we\u0000find infrared excess at the significance level of 1.5 $sigma$ for WISE W1 and\u0000W2 bands, and 2 $sigma$ level for W3 and W4 bands. This potentially reveals\u0000the existence of a stellar disk, consisting of hot dust at 800$pm$300 K,\u0000showing a $L_{dust}/L_{ast}$ of 5$pm$3$times$10$^{-3}$. We obtain a stellar\u0000age of 1.0$^{+1.4}_{-0.7}$$times$10$^{9}$ yr from isochrone fitting. The\u0000properties of K2-237b potentially serve as a direct observational support to\u0000the planet disk migration though more observation are needed.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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