Journal of Astrophysics and Astronomy最新文献_第9页

Conjunction of planets: procedures and examples from Indian astronomy texts 行星会合：印度天文学文献中的程序和例子

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-08-29 DOI: 10.1007/s12036-023-09967-3

B. S. Shylaja, B. S. Shubha

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Revisiting the old end of the Milky Way open cluster age function 重温银河系开放星团年龄函数的旧端

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-08-23 DOI: 10.1007/s12036-023-09970-8

Andrés E. Piatti

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Higher dimensional Bianchi type-III string cosmological models with dark energy in Saez–Ballester scalar-tensor theory of gravitation Saez–Ballester标量张量引力理论中具有暗能量的高维Bianchi III型弦宇宙学模型

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-08-19 DOI: 10.1007/s12036-023-09971-7

R. K. Dabgar, A. K. Bhabor

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Protoplanetary disks around young stellar and substellar objects in the ({sigma }) Orionis cluster σdocumentclass[12pt]｛minimum｝usepackage｛amsmath｝usepackage｛wasysym｝usepackup｛amsfonts｝usecpackage{amssymb｝usecpacket｛amsbsy｝ucepackage{mathrsfs｝userpackage{upgeek｝setlength｛doddsidemargin｝｛-69pt｝start｛document中年轻恒星和亚恒星物体周围的原行星盘

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-08-16 DOI: 10.1007/s12036-023-09968-2

Belinda Damian, Jessy Jose, Beth Biller, K. T. Paul

{"title":"Protoplanetary disks around young stellar and substellar objects in the ({sigma }) Orionis cluster","authors":"Belinda Damian, Jessy Jose, Beth Biller, K. T. Paul","doi":"10.1007/s12036-023-09968-2","DOIUrl":"10.1007/s12036-023-09968-2","url":null,"abstract":"<div>Understanding the evolution and dissipation of protoplanetary disks are crucial in star and planet formation studies. We report the protoplanetary disk population in the nearby young (sigma ) Orionis cluster ((dsim 408) pc; (textrm{age}sim 1.8) Myr) and analyse the disk properties, such as dependence on stellar mass and disk evolution. We utilize the comprehensive census of 170 spectroscopic members of the region refined using astrometry from Gaia DR3 for a wide mass range of (sim )19–0.004 (M_odot ). Using the near-infrared (2MASS) and mid-infrared (WISE) photometries, we classify the sources based on the spectral index, into class I, class II, flat spectrum and class III young stellar objects. The frequency of sources hosting a disk with stellar mass <2 (M_odot ) in this region is (41pm 7)%, which is consistent with the disk fraction estimated in previous studies. We see that there is no significant dependence of disk fraction on stellar mass among T Tauri stars (<2 (M_odot )), but we propose rapid disk depletion around higher mass stars (>2 (M_odot )). Furthermore, we found the lowest mass of a disk-bearing object to be (sim )20 (M_{textrm{Jup}}) and the pronounced disk-fraction among the brown dwarf population hints at the formation scenario that brown dwarfs form similar to low-mass stars.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44134420","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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Investigating star-formation activity in Sh 2-61 H ii region 研究Sh2-61Hii区域的恒星形成活动

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-08-05 DOI: 10.1007/s12036-023-09966-4

Rakesh Pandey, Saurabh Sharma, Lokesh Dewangan, Aayushi Verma, Tapas Baug, Harmeen Kaur, Arpan Ghosh

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Estimation of stellar parameters and mass accretion rate of classical T Tauri stars from LAMOST DR6 LAMOST DR6对经典金牛座T星的恒星参数和质量吸积率的估计

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-07-28 DOI: 10.1007/s12036-023-09965-5

S. Nidhi, Blesson Mathew, B. Shridharan, Suman Bhattacharyya, D. Edwin, Sreeja S. Kartha

{"title":"Estimation of stellar parameters and mass accretion rate of classical T Tauri stars from LAMOST DR6","authors":"S. Nidhi, Blesson Mathew, B. Shridharan, Suman Bhattacharyya, D. Edwin, Sreeja S. Kartha","doi":"10.1007/s12036-023-09965-5","DOIUrl":"10.1007/s12036-023-09965-5","url":null,"abstract":"<div>Classical T Tauri stars (TTS) are low-mass pre-main sequence stars with an active circumstellar environment. In this work, we present the identification and study of 260 classical TTS using LAMOST Data Release 6, among which 104 stars are newly identified. We distinguish classical TTS from giants and main-sequence dwarfs based on the (log {g}) values, and the presence of H(alpha ) emission line and infrared excess that arises from the circumstellar accretion disk. We estimated the mass and age of 210 stars using the Gaia color–magnitude diagram. The age is from 0.1 to 20 Myr, where 90% of the stars have age <10 Myr and the mass ranges between 0.11 and 1.9 (M_{odot }). From the measured H(alpha ) equivalent widths, we homogeneously estimated the mass accretion rates for 172 stars, with most values ranging from (10^{-7}) to (10^{-10}) (M_{odot }) yr(^{-1}). The mass accretion rates are found to follow a power law distribution with the mass of the star, having a relation of the form (dot{M}_textrm{acc}propto M_{*} ^ {1.43 pm 0.26}), in agreement with previous studies.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42249959","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}

引用次数: 0

Diving deep into the milky way using anti-reflection coatings for astronomical CCDs 使用天文CCD防反射涂层深入银河系

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-07-21 DOI: 10.1007/s12036-023-09962-8

Anmol Aggarwal, Ashi Mittal, George M. Seabroke, Nitin K. Puri

引用次数: 0

On dispersion and damping rates of dust-acoustic waves in hybrid non-thermal Vasyliunas–Cairns distributed plasmas 非热Vasyliunas-Cairns混合等离子体中尘埃-声波的色散和阻尼率

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-07-19 DOI: 10.1007/s12036-023-09963-7

Muhammad Ahsan Shahzad, Muhammad Sarfraz, Aman-Ur-Rehman, Shahzad Mahmood, Muhammad Bilal, Hashim Farooq

{"title":"On dispersion and damping rates of dust-acoustic waves in hybrid non-thermal Vasyliunas–Cairns distributed plasmas","authors":"Muhammad Ahsan Shahzad, Muhammad Sarfraz,  Aman-Ur-Rehman, Shahzad Mahmood, Muhammad Bilal, Hashim Farooq","doi":"10.1007/s12036-023-09963-7","DOIUrl":"10.1007/s12036-023-09963-7","url":null,"abstract":"<div>The dispersion relation and Landau damping rate of dust-acoustic waves (DAWs) are studied by the incorporation of Poison–Vlasov model of the kinetic theory of plasmas. The real and imaginary frequencies of DAWs are obtained in a three-component plasma i.e., electrons, ions and dust grains. The electrons are taken as hybrid non-thermal Vasyliunas–Cairns distributed and in limiting cases as kappa and Cairns distributed as well, while the ions and dust are kept Maxwellian. The findings reveal that the simultaneous presence of two non-thermality parameters (i.e., (alpha ) and (kappa )) have a remarkable impact on the dispersion and damping rates of DAWs as compared to the sole presence of any non-thermality parameter and also in the case of thermal electrons. It is also presented that the real and imaginary frequencies of DAWs are significantly influenced by the other important parameters, such as electron to ion temperature and density ratios. This work has notable significance in the understanding of important constituents of space plasmas i.e., thermal and non-thermal dusty plasmas in various environments of space plasmas, where the mixed particle distributions are observed.\u0000</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4752436","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}

引用次数: 0

Study of secondary cosmic rays using small stratospheric balloon missions 利用小型平流层气球任务研究次级宇宙射线

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-07-19 DOI: 10.1007/s12036-023-09964-6

RUPNATH SIKDAR, SANDIP K. CHAKRABARTI, DEBASHIS BHOWMICK

{"title":"Study of secondary cosmic rays using small stratospheric balloon missions","authors":"RUPNATH SIKDAR, SANDIP K. CHAKRABARTI, DEBASHIS BHOWMICK","doi":"10.1007/s12036-023-09964-6","DOIUrl":"10.1007/s12036-023-09964-6","url":null,"abstract":"<div>Secondary cosmic rays are produced from the interaction of primary cosmic rays, which are high-energy ((sim )GeV) particles originating from outer space, primarily, protons ((sim )89%) and alpha particles ((sim )10%) with atoms (mainly nitrogen and hydrogen) present in our Earth’s atmosphere. Such rays are dependent on solar activity and geomagnetic latitude through magnetic rigidity and are found to be modulated by these factors. For analysis of secondary cosmic ray data, we use the Indian Centre for Space Physics’s data obtained through small stratospheric balloon-borne experiments. In the present paper, we have measured the secondary cosmic ray intensity at low geomagnetic latitude of (sim )14.50(^circ )N in the low energy range of 25–60 keV from the ground to 30 km altitude for different detectors used in various balloon missions because such missions are almost detecting the X-ray sources above 30 km till 42 km. We also calculated background flux of the detector with the help of some justifiable physical assumptions, secondary cosmic gamma-ray component measurements, and assumed internal background functions. Finally, using our data of 2012–2019, which falls in the 24th solar cycle, we have shown that there is a clear anti-correlation between cosmic ray intensity at Regener–Pfotzer maximum and the solar activity.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4752439","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}

引用次数: 0

Statistical analysis of dynamical evolution of open clusters 开放星团动态演化的统计分析

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-07-10 DOI: 10.1007/s12036-023-09959-3

Jayanand Maurya, Y. C. Joshi, Manash Ranjan Samal, Vineet Rawat, Anubha Singh Gour

{"title":"Statistical analysis of dynamical evolution of open clusters","authors":"Jayanand Maurya, Y. C. Joshi, Manash Ranjan Samal, Vineet Rawat, Anubha Singh Gour","doi":"10.1007/s12036-023-09959-3","DOIUrl":"10.1007/s12036-023-09959-3","url":null,"abstract":"<div>We present the dynamical evolution of 10 open clusters, which were part of our previous studies. These clusters include both young and intermediate-age open clusters with ages ranging from (25 pm 19) Myr to (1.78pm 0.20) Gyr. The total mass of these clusters ranges from (356.18pm 142.90) to (1811.75pm ~901.03) (M_{odot }). The Galactocentric distances to the clusters are in the range of (8.91pm 0.02)–(11.74pm 0.18) kpc. The study is based on the ground-based UBVRI data supplemented by the astrometric data from the Gaia archive. We studied the minimum spanning tree of the member stars for these clusters. The mass segregation in these clusters was quantified by mass segregation ratios calculated from the mean edge length obtained through the minimum spanning tree. The clusters NGC 2360, NGC 1960, IC 1442, King 21 and SAI 35 have (Gamma _textrm{MSR}) to be (1.65pm 0.18), (1.94pm 0.22), (2.21pm 0.20), (1.84pm 0.23) and (1.96pm 0.25), respectively, which indicate moderate mass segregation in these clusters. The remaining five clusters are found to exhibit weak or no mass segregation. We used the ratio of half mass radius to the tidal radius i.e., (R_{h}/R_{t}) to investigate the effect of the tidal interactions on the cluster structure and dynamics. The ratios of half mass radii to tidal radii are found to be positively correlated with the Galactocentric distances with a linear slope of (0.06pm 0.01) having linear regression coefficient r-square (=) 0.93 for the clusters.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"44 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12036-023-09959-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4423301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0