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Gap opening by planets in discs with magnetised winds 行星在带磁化风的圆盘中打开间隙
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1093/mnras/stac1774
V. Elbakyan, Yinhao Wu, S. Nayakshin, G. Rosotti
{"title":"Gap opening by planets in discs with magnetised winds","authors":"V. Elbakyan, Yinhao Wu, S. Nayakshin, G. Rosotti","doi":"10.1093/mnras/stac1774","DOIUrl":"https://doi.org/10.1093/mnras/stac1774","url":null,"abstract":"Abstract Planets open deep gaps in protoplanetary discs when their mass exceeds a gap opening mass, Mgap. We use one- and two-dimensional simulations to study planet gap opening in discs with angular momentum transport powered by MHD disc winds. We parameterise the efficiency of the MHD disc wind angular momentum transport through a dimensionless parameter αdw, which is an analogue to the turbulent viscosity αv. We find that magnetised winds are much less efficient in counteracting planet tidal torques than turbulence is. For discs with astrophysically realistic values of αdw, Mgap is always determined by the residual disc turbulence, and is a factor of a few to ten smaller than usually obtained for viscous discs. We introduce a gap opening criterion applicable for any values of αv and αdw that may be useful for planet formation population synthesis.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84332473","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}
引用次数: 2
Is star formation in gas-rich bars suppressed? 在富含气体的棒状结构中恒星的形成是否受到抑制?
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322003775
F. Maeda
{"title":"Is star formation in gas-rich bars suppressed?","authors":"F. Maeda","doi":"10.1017/S1743921322003775","DOIUrl":"https://doi.org/10.1017/S1743921322003775","url":null,"abstract":"Abstract Whether the star formation efficiency (SFE) in the bar region is lower than those in the other regions in a barred galaxy has recently been debated. We statistically investigate the SFEs along the bars in nearby gas-rich massive star-forming barred galaxies by distinguishing the center, bar-end, and bar regions for the first time. The molecular gas surface density is derived from archival CO(1–0) and/or CO(2–1) data and the star formation rate surface density is derived from a linear combination of far-ultraviolet and mid-infrared intensities. To distinguish the three regions, we targeted 18 galaxies with a large apparent bar length (≥ 75\"). The resulting SFE in the bars is about 0.6 – 0.8 times lower than that in the disks, which suggests the star formation in the bars tends to be systematically suppressed.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79755607","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}
引用次数: 0
To the dynamics of the two-body problem with variable masses in the presence of reactive forces 在反力作用下变质量两体问题的动力学
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S174392132200360X
A. Ibraimova, M. Minglibayev
{"title":"To the dynamics of the two-body problem with variable masses in the presence of reactive forces","authors":"A. Ibraimova, M. Minglibayev","doi":"10.1017/S174392132200360X","DOIUrl":"https://doi.org/10.1017/S174392132200360X","url":null,"abstract":"Abstract We studied the problem of two spherical celestial bodies in the general case when the masses of the bodies change non-isotropically at different rates in the presence of reactive forces. The problem was investigated by methods of perturbation theory based on aperiodic motion along a quasi-conic section, using the equation of perturbed motion in the form of Newton’s equations. The problem is described by the variables a, e, i, π, ω, λ, which are analogs of the corresponding Keplerian elements and the equations of motion in these variables are obtained. Averaging over the mean longitude, we obtained the evolution equations of the two-body problem with variable masses in the presence of reactive forces. The obtained evolution equations have the exact analytic integral ${a^3 e^4 = a^3_0 e^4_0} = {const}$ .","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82554680","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}
引用次数: 0
Anatomy of Galactic Star Formation: Roles of Different Modes of Gas Accretion, Feedback, and Recycling 银河恒星形成的解剖:不同模式的气体吸积、反馈和再循环的角色
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322004823
M. Noguchi
{"title":"Anatomy of Galactic Star Formation: Roles of Different Modes of Gas Accretion, Feedback, and Recycling","authors":"M. Noguchi","doi":"10.1017/S1743921322004823","DOIUrl":"https://doi.org/10.1017/S1743921322004823","url":null,"abstract":"Abstract Existence of the cold-mode gas accretion along with the hot-mode accretion can explain the diversity in the galactic star formation history across galaxy mass. We examine the role of various physical processes in producing the observed diversity.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91048342","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}
引用次数: 0
Star formation history for the starburst dwarf galaxy in the Local Group, IC 10 本星系群ic10星暴矮星系的恒星形成历史
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322004914
Mahtab Gholami, A. Javadi, J. V. van Loon, H. Khosroshahi, E. Saremi
{"title":"Star formation history for the starburst dwarf galaxy in the Local Group, IC 10","authors":"Mahtab Gholami, A. Javadi, J. V. van Loon, H. Khosroshahi, E. Saremi","doi":"10.1017/S1743921322004914","DOIUrl":"https://doi.org/10.1017/S1743921322004914","url":null,"abstract":"Abstract IC 10 as a starburst dwarf galaxy in the Local Group (LG) has a large population of newly formed stars that are massive and intrinsically very bright in comparison with other LG galaxies. Using the Isaac Newton Telescope (INT) with the Wide Field Camera (WFC) in the i-band and V-band, we performed an optical monitoring survey to identify the most evolved asymptotic giant branch stars (AGBs) and red supergiant stars (RSGs) in this star-forming galaxy, which can be used to determine the star formation history (SFH). The E(B - V) as an effective factor for obtaining the precise magnitude of stars is measured for each star using a 2D dust map (SFD98) to obtain a total extinction for each star in both the i-band and V-band. We obtained the photometric catalog for 53579 stars within the area of 0.07 deg2 (13.5 kpc2), of which 762 stars are classified as variable candidates after removing the foreground stars and saturated ones from our catalog. To reconstruct the SFH for IC 10, we first identified 424 long-period variable (LPV) candidates within the area of two half-light radii (2r h ) from the center of the galaxy. We estimated the recent star formation rate (SFR) at ∼ 0.32 yr-1 for a constant metallicity Z = 0.0008, showing the galaxy is currently undergoing high levels of star formation. Also, a total stellar mass of is obtained within 2r h for that metallicity.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79080451","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}
引用次数: 0
Size Evolution and Orbital Architecture of KEPLER Small Planets through Giant Impacts and Photoevaporation 通过巨大撞击和光蒸发，开普勒小行星的大小演化和轨道结构
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322003970
P. Gu, Matsumoto Yuji, Kokubo Eiichiro, Kurosaki Kenji
{"title":"Size Evolution and Orbital Architecture of KEPLER Small Planets through Giant Impacts and Photoevaporation","authors":"P. Gu, Matsumoto Yuji, Kokubo Eiichiro, Kurosaki Kenji","doi":"10.1017/S1743921322003970","DOIUrl":"https://doi.org/10.1017/S1743921322003970","url":null,"abstract":"Abstract The KEPLER transit survey with follow-up spectroscopic observations has discovered numerous small planets (super-Earths/sub-Neptunes) and revealed intriguing features of their sizes, orbital periods, and their relations between adjacent planets. The planet size distribution exhibits a bimodal distribution separated by a radius gap at around 1.8 Earth radii. Besides, these small planets within multiple planetary systems show that adjacent planets are similar in size and their period ratios of adjacent planet pairs are similar as well, a phenomenon often dubbed as peas-in-a-pod in the exoplanet community. While the radius gap has been predicted and theorized for years, whether it can be relevant to the orbital architecture peas-in-a-pod is physically unknown. For the first time, we attempted to model both features together through planet formation and evolution processes involving giant impacts and photoevaporation. We showed that our model is generally consistent with the KEPLER results but with a smaller radius gap. The impact of Kubyshikina’s model for photoevaporation on our model is discussed.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73613422","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}
引用次数: 0
Variation of the molecular cloud lifecycle across the nearby galaxy population 分子云生命周期在邻近星系群中的变化
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322003738
Jaeyeon Kim, M. Chevance, J. M. Diederik Kruijssen, A. Leroy
{"title":"Variation of the molecular cloud lifecycle across the nearby galaxy population","authors":"Jaeyeon Kim, M. Chevance, J. M. Diederik Kruijssen, A. Leroy","doi":"10.1017/S1743921322003738","DOIUrl":"https://doi.org/10.1017/S1743921322003738","url":null,"abstract":"Abstract The processes of star formation and feedback take place on the scales of giant molecular clouds (GMCs; ~ 100 pc) within galaxies and play a major role in governing galaxy evolution. By applying a robust statistical method to PHANGS observations, we systematically measure the evolutionary timeline from molecular clouds to exposed young stellar regions, across an unprecedented sample of 54 galaxies. These timescales depend on galaxy environment, revealing the role of galactic-scale dynamical processes in the small-scale GMC evolution. Furthermore, in the 5 nearest galaxies of our sample, we have refined the GMC timeline further and established the duration of the heavily obscured phase, using 24 μm emission. These results represent a major first step towards a comprehensive picture of cloud assembly and feedback, which will be extended to 19 more galaxies with our ongoing JWST Large Program.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75532684","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}
引用次数: 0
The density structure of molecular cloud scales: A fitting for N-PDF with multi log-normal functions 分子云尺度的密度结构:N-PDF的多对数正态函数拟合
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322004379
T. Murase, T. Handa, Ren Matsusaka, Y. Shimajiri, Masato I. N. Kobayashi, M. Kohno, J. Nishi, N. Takeba, Yosuke Shibata
{"title":"The density structure of molecular cloud scales: A fitting for N-PDF with multi log-normal functions","authors":"T. Murase, T. Handa, Ren Matsusaka, Y. Shimajiri, Masato I. N. Kobayashi, M. Kohno, J. Nishi, N. Takeba, Yosuke Shibata","doi":"10.1017/S1743921322004379","DOIUrl":"https://doi.org/10.1017/S1743921322004379","url":null,"abstract":"Abstract We studied the probability distribution function of the column density (N-PDF) of molecular clouds based on a fit with a multi-log-normal function using the Nobeyama 45-m Cygnus X CO survey data. We identified 124 molecular clouds in 13CO data using the DENDROGRAM and SCIMES algorithms. The N-PDF was constructed for 11 extended (≥ 0.4 deg2) molecular clouds of these identified clouds. We found that every N-PDF is well-fitted with one or two log-normal (LN) distributions. We investigated the distributions of the column density, C18O dense cores, and radio continuum source in each cloud and found that the N-PDF was less correlated with the star-forming activity. The LN N-PDF parameters showed two impressive features. First, the LN distribution at the low-density part had the same mean column density (∼1021.5 cm−2 ) for almost all the molecular clouds. Second, the wider LN distribution tended to show the lower mean density of the structures.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75622281","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}
引用次数: 0
Statistical properties of cold circumstellar envelops observed in NESS–NRO NESS-NRO观测到的冷星周包层的统计性质
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921323001783
K. Amada, S. Fukaya, H. Imai, P. Scicluna, N. Hirano, A. Trejo-Cruz, S. Zeegers, F. Kemper, S. Srinivasan, S. Wallström, T. Dharmawardena, H. Shinnaga
{"title":"Statistical properties of cold circumstellar envelops observed in NESS–NRO","authors":"K. Amada, S. Fukaya, H. Imai, P. Scicluna, N. Hirano, A. Trejo-Cruz, S. Zeegers, F. Kemper, S. Srinivasan, S. Wallström, T. Dharmawardena, H. Shinnaga","doi":"10.1017/S1743921323001783","DOIUrl":"https://doi.org/10.1017/S1743921323001783","url":null,"abstract":"Abstract We conducted CO J=1→0 emission line observations for nearby AGB stars using the Nobeyama 45 m telescope. Comparing our results with those from CO J=3→2 observations with JCMT, the circumstellar envelopes observed in CO J=1→0 look more extended than J=3→2. Thus, we could trace the outer, cold parts of the envelopes. We also found four stars in which the CO/13CO ratio changes dramatically outward, but the change implies the effect of selective photodissociation by interstellar ultraviolet radiation, not the third dredge up in the stellar interior. We moreover found two unique stars with aspherical envelope morphology.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75834384","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}
引用次数: 1
Physics of the atmospheric escape driven by EUV photoionization heating: Classification of the hydrodynamic escape in close-in planets 由极紫外光离加热驱动的大气逸出的物理学:近地行星流体动力学逸出的分类
Proceedings of the International Astronomical Union Pub Date : 2021-08-01 DOI: 10.1017/S1743921322003556
Hiroto Mitani, Riouhei Nakatani, N. Yoshida
{"title":"Physics of the atmospheric escape driven by EUV photoionization heating: Classification of the hydrodynamic escape in close-in planets","authors":"Hiroto Mitani, Riouhei Nakatani, N. Yoshida","doi":"10.1017/S1743921322003556","DOIUrl":"https://doi.org/10.1017/S1743921322003556","url":null,"abstract":"Abstract The intense extreme ultraviolet radiation heats the upper atmosphere of close-in exoplanets and drives the atmospheric escape. The escaping process determines the planetary evolution of close-in planets. The mass loss rate depends on the UV flux at the planet. We introduce the relevant physical quantities which describe the dominant physics in the atmosphere. We find that the equilibrium temperature and the characteristic temperature determine whether the system becomes energy-limited or recombination-limited. We classify the observed close-in planets using the physical conditions. We also find that many of the Lyman-α absorptions detected planets receive intenser flux than the critical flux which can be determined from physical conditions. Our classification method can quantitatively reveal whether the EUV is not strong enough to drive the outflow or the Lyman- α absorption is not detected for some reason (e.g. stellar wind confinement). We also discuss the thermo-chemical structure of hydrodynamic simulations with the relevant physics.","PeriodicalId":20590,"journal":{"name":"Proceedings of the International Astronomical Union","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90391440","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}
引用次数: 0
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