YNAO OpenIR
中国科学院云南天文台
http://ir.ynao.ac.cn:80
2024-03-19T13:31:21Z
2024-03-19T13:31:21Z
Interstellar scintillation observations for PSR J0835-4510 at 6656 MHz
Xu YH(徐永华)
Shi, Xun
Lee, Kejia
Hao LF(郝龙飞)
Li ZX(李志玄)
Wang M(汪敏)
Yuan, Jianping
Xu, Heng
Wu, Ziwei
Jiang, Jinchen
Huang YX(黄玉祥)
Wang, Bojun
Shen FX(沈发新)
Cao S(曹朔)
http://ir.ynao.ac.cn:80/handle/114a53/26368
2023-11-07T00:57:00Z
2023-11-07T00:53:56Z
题名: Interstellar scintillation observations for PSR J0835-4510 at 6656 MHz
作者: Xu YH(徐永华); Shi, Xun; Lee, Kejia; Hao LF(郝龙飞); Li ZX(李志玄); Wang M(汪敏); Yuan, Jianping; Xu, Heng; Wu, Ziwei; Jiang, Jinchen; Huang YX(黄玉祥); Wang, Bojun; Shen FX(沈发新); Cao S(曹朔)
摘要: <p>Scintillation phenomena of pulsars provide an important tool for studying interstellar scattering screens and their properties. In this paper, we report pulsar scintillation phenomena of the PSR J0835-4510 at multiple epochs between MJD 58592 and MJD 58843 using the Kunming 40 m radio telescope at a centre frequency of 6656 MHz. We have measured the dynamic spectrum, and derived the scintillation time, bandwidth, and secondary spectrum at each observation epoch. For the first time, we report the detection of parabolic arc structure in the secondary spectra of PSR J0835-4510. Parabolic arcs with varying curvatures appear at all our observation epochs. We used both anisotropic and isotropic scattering screen models to fit the annual variations of arc curvature. While both models can fit the arc curvature variations equally well, the anisotropic model also explains the parabolic arc morphology and its time variation. In this model, the scattering is located at a fractional distance of s = 0.35 ± 0.10, or a distance Ds = 0.19 ± 0.03 kpc from the Earth, likely corresponding to the boundary of the Local Bubble. © 2023 The Author(s).</p>
2023-11-07T00:53:56Z
Type Ia supernovae in NS+He star systems and the isolated mildly recycled pulsars
Guo YL(郭云浪)
Wang B(王博)
Wu CY(吴程远)
Chen, Wen-Cong
Jiang, Long
Han ZW(韩占文)
http://ir.ynao.ac.cn:80/handle/114a53/26367
2023-11-07T00:55:25Z
2023-11-07T00:53:55Z
题名: Type Ia supernovae in NS+He star systems and the isolated mildly recycled pulsars
作者: Guo YL(郭云浪); Wang B(王博); Wu CY(吴程远); Chen, Wen-Cong; Jiang, Long; Han ZW(韩占文)
摘要: <p>Type Ia supernovae (SNe Ia) are successful cosmological distance indicators and important element factories in the chemical evolution of galaxies. They are generally thought to originate from thermonuclear explosions of carbon-oxygen white dwarfs in close binaries. However, the observed diversity among SNe Ia implies that they have different progenitor models. In this article, we performed the long-term evolution of NS+He star binaries with different initial He star masses () and orbital periods () for the first time, in which the He star companions can explode as SNe Ia eventually. Our simulations indicate that after the He stars develop highly degenerate oxygen-neon (ONe) cores with masses near the Chandrasekhar limit, explosive oxygen burning can be triggered due to the convective Urca process. According to these calculations, we obtained an initial parameter space for the production of SNe Ia in the plane. Meanwhile, we found that isolated mildly recycled pulsars can be formed after He stars explode as SNe Ia in NS+He star binaries, in which the isolated pulsars have minimum spin periods () of ∼30-110 ms and final orbital velocities of, corresponding to initial orbital periods of 0.07-10 d. Our work suggests that the NS+He star channel may contribute to the formation of isolated mildly recycled pulsars with velocity in observations, and such isolated pulsars should locate in the region of pulsars with massive white dwarf companions in the diagram. © 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.</p>
2023-11-07T00:53:55Z
激光测距中激光功率实时监测系统设计与实现
吴凡
翟东升
李祝莲
汤儒峰
皮晓宇
李语强
http://ir.ynao.ac.cn:80/handle/114a53/26366
2023-12-25T18:00:09Z
2023-11-06T09:13:01Z
题名: 激光测距中激光功率实时监测系统设计与实现
作者: 吴凡; 翟东升; 李祝莲; 汤儒峰; 皮晓宇; 李语强
摘要: <p>Objective In laser ranging processes, Single-Photon Avalanche Diode (SPAD) is commonly used as a detector. However, this type of detector exhibits a time-walk effect, where different input energies result in different photon detection times. In such cases, it is necessary to monitor the laser power in real-time to analyze the variations in laser energy and the impact of the detector itself on ranging accuracy. Furthermore, due to the complexity of satellite laser ranging systems, troubleshooting typically requires a significant amount of time. Real-time monitoring of laser power allows for quick identification and troubleshooting of laser transmitter energy, reducing the time required for identifying system faults. Therefore, obtaining real-time laser emission power data serves as a crucial basis for subsequent analysis of data accuracy and troubleshooting of laser ranging system faults. Methods To address the limitations of traditional real-time laser power monitoring techniques, such as laser energy attenuation, susceptibility to introducing optical axis deviation, and difficulties in practical application, a real-time laser power monitoring method is proposed for laser ranging systems. Here is the method: Beforeranging, insert laser power meter II into the optical path and adjust the laser diode current to obtain multiple sets of different laser emission powers. Use laser power meters I and II to measure the transmitted light and reflected light from the reflector respectively, establishing the corresponding relationship between transmitted and reflected light (Fig. 4). During ranging, remove laser power meter II from the optical path, and laser power meter I continuously measures the transmitted light from the reflector in the laser emission path (Fig. 3). Utilize the previously established corresponding relationship between transmitted and reflected light to obtain real-time reflected light power through relative measurement. This achieves the effect of real-time monitoring of laser emission power. Validate the method by constructing an experimental platform based on the 53 cm dual-tube telescope at Yunnan Observatory. Results and Discussions By adjusting the laser diode current to change the laser power, multiple sets of data for the transmitted laser power and reflected laser power were measured. The data was then used to perform a linear fit using the least squares method. The significance of the regression equation was evaluated using the Ftest, yielding an F-value of 3 171. 039 5. Consulting the F-distribution table revealed that the regression was highly significant, indicating a strong linear relationship between the reflected and transmitted laser powers. The residual standard deviation (σ) of the regression equation was found to be 0. 007 3. The maximum deviation between the measured values of reflected laser power and the fitted results was 1. 49% of the current measurement, demonstrating that the regression line accuracy meets the requirements for laser ranging (Fig. 5). The proposed method was subjected to intermittent measurements over a duration of 7 hours. The F-value obtained from the F-test was 1 057. 777 9, which means the regression was still highly significant. The residual standard deviation (σ) was calculated to be 0. 016 5, and the maximum deviation value of the reflected laser power measurement from the fitted result is 3. 75% of the current measurement value. This meets the accuracy requirements, demonstrating that the proposed method can maintain long-term stability and fulfill the needs of long-time satellite laser ranging (Fig. 6). Conclusions The experimental results indicate that the proposed method of real-time laser power monitoring can accurately obtain the laser emission power without loss in the laser emission path. The reflected laser power and transmitted laser power exhibit a strong linear relationship, with a Spearman correlation coefficient of 0. 999 1. This linear relationship remains stable and reliable during long-duration laser ranging experiments. The feasibility of this method has been verified, meeting the power measurement requirements for laser ranging of various spatial targets. Therefore, this method can be applied to the real-time monitoring of laser power for various spatial objects laser ranging.</p>
摘要: <p>在激光测距过程中,实时获取激光发射功率数据可为后续数据精度处理分析及激光测距系统故障点排查提供重要依据。通过实时测量激光发射链路中的反射镜透射光,利用前期获取的反射镜透射光与反射镜反射光之间的对应关系,采取相对测量的方式获取实时的反射光功率,达到实时监测激光发射功率的效果,并基于中国科学院云南天文台53 cm双筒望远镜激光测距系统搭建实验平台进行验证。实验结果表明,该激光功率实时监测方法能够在激光发射链路无损耗的前提下实时获取激光发射功率;反射光功率与透射光功率具有良好的线性关系,其Spearman相关系数为0.999 1,线性关系稳定可靠,满足长时间激光测距的需求;验证了该方法的可行性,可适用于各类空间目标激光测距的激光功率实时监测中。 </p>
2023-11-06T09:13:01Z
大孔径全可动射电望远镜换馈系统设计
杨凤辉
汪敏
董亮
施硕彪
http://ir.ynao.ac.cn:80/handle/114a53/26365
2024-01-14T18:00:04Z
2023-11-06T09:13:00Z
题名: 大孔径全可动射电望远镜换馈系统设计
作者: 杨凤辉; 汪敏; 董亮; 施硕彪
摘要: <p>In order to further meet the needs of lunar exploration, deep space exploration and other astronomical observation tasks, the Kunming 40 m aperture fully movable radio telescope, which was equipped with only one S/X dual-frequency feed source at the initial stage of design, was upgraded and its feed switching system was developed. On the basis of not changing the existing antenna structure and optical path, the original S/X dual-frequency feed source was removed, a new S/X dual-frequency feed source was installed, and the C and Ku frequency feed sources were added. The detailed design and implementation schemes of the feed switching system were given, and the automatic, fast and reliable switching among the three feed sources was realized. The performance of the antenna after feed modification was tested, and the results showed that the main performance indexes of the antenna were improved. After the modification of the feed source and feed switching system, the large aperture fully movable radio telescope had the ability to receive multiple frequency bands, and can complete the astronomical observation and deep space exploration tasks with more frequency bands, improving the observation efficiency and scientific research output of the telescope.</p>
摘要: <p>为了进一步满足探月工程、深空探测和其他天文观测任务的需求,对设计初期只配置了一个S/X双频馈源的昆明40 m孔径全可动射电望远镜进行升级改造,研制了其换馈系统。在不改变现有天线结构及光路的基础上,拆除了原S/X双频馈源,安装了新的S/X双频馈源,并增加了C频段、Ku频段馈源;给出了换馈系统的详细设计和实施方案,实现了3个馈源间自动快速可靠的切换。对馈源改造之后的天线性能进行了测试,结果表明,天线的主要性能指标有所提升。馈源及换馈系统改造之后,大孔径全可动射电望远镜具有多频段接收能力,能够完成更多频段的天文观测和深空探测任务,提高了望远镜的观测效率和科研产出。 </p>
2023-11-06T09:13:00Z
An Update of the Catalog of Radial Velocity Standard Stars from the APOGEE DR17
Li QZ(李清政)
Huang, Yang
Dong XB(董小波)
Chen, Jian-Jun
Luo, A-Li
http://ir.ynao.ac.cn:80/handle/114a53/26364
2023-11-06T08:33:32Z
2023-11-06T08:23:38Z
题名: An Update of the Catalog of Radial Velocity Standard Stars from the APOGEE DR17
作者: Li QZ(李清政); Huang, Yang; Dong XB(董小波); Chen, Jian-Jun; Luo, A-Li
摘要: <p>We present an updated catalog of 46,753 radial velocity (RV) standard stars selected from the APOGEE DR17. These stars cover the Northern and Southern Hemispheres almost evenly, with 62% being red giants and 38% being main sequence stars. These RV standard stars are stable on a baseline longer than 200 days (with 54% longer than one year and 10% longer than five years) with a median stability better than 215 m s(-1). The average number of observations of those stars is 5 and each observation is required to have signal-to-noise ratio greater than 50 and RV measurement error smaller than 500 m s(-1). Based on the new APOGEE RV standard star catalog, we have checked the RV zero-points (RVZPs) for current large-scale stellar spectroscopic surveys including RAVE, LAMOST, GALAH and Gaia. By careful analysis, we estimate their mean RVZP to be +0.149 km s(-1), +4.574 km s(-1) (for LRS), -0.031 km s(-1) and +0.014 km s(-1), respectively, for the four surveys. In the RAVE, LAMOST (for MRS), GALAH and Gaia surveys, RVZP exhibits a systematic trend with stellar parameters (mainly [Fe/H], T-eff, log g, G(BP) - G(RP) and G(RVS)). The corrections to those small but clear RVZPs are of vital importance for these massive spectroscopic surveys in various studies that require extremely high RV accuracies.</p>
2023-11-06T08:23:38Z
一种基于多特征融合的太阳耀斑预报方法
邓林华
徐永华
向南彬
蔡云芳
向永源
http://ir.ynao.ac.cn:80/handle/114a53/26355
2023-10-31T00:41:33Z
2023-10-31T00:39:12Z
题名: 一种基于多特征融合的太阳耀斑预报方法
作者: 邓林华; 徐永华; 向南彬; 蔡云芳; 向永源
摘要: 本发明公开了一种基于多特征融合的太阳耀斑预报方法,包括以下步骤:S1:获取一定时间内的太阳观测数据,并从中提取预报因子和耀斑爆发数据,不同预报因子采用a、b、c……标示,不同耀斑爆发数据采用α、β、γ……标示;S2:采用不同预报因子和耀斑爆发数据构建数据集,且每个预报因子均需要与每个耀斑爆发数据进行对应构建,不同数据集采用(a,α)、(a,β)、(a,γ)……标示,再将每个数据集分为训练集和测试集。本发明通过将多种预测因子与计算模型对太阳耀斑的发生进行预测,并通过结果模型对计算模型所得出的结果集进行总结修正,从而能够得出置信度更高的结果,有效地提高了模型对太阳耀斑预报的准确性。
2023-10-31T00:39:12Z
一种用于科普展示的赤道式电子日晷
王贞珍
王传军
余晓光
汪洵浩
http://ir.ynao.ac.cn:80/handle/114a53/26354
2023-10-31T00:40:33Z
2023-10-31T00:39:11Z
题名: 一种用于科普展示的赤道式电子日晷
作者: 王贞珍; 王传军; 余晓光; 汪洵浩
摘要: 本实用新型公开了一种用于科普展示的赤道式电子日晷,包括底座,所述底座顶部安装有电子日晷结构,所述电子日晷结构包含有:立柱、步进电机、横轴、晷面、晷针、若干光敏电阻传感器、系统板以及显示组件,本实用新型涉及天文科普教育教具改进技术领域,本案的有益效果为:本实用新型提供了一种用于科普展示的赤道式电子日晷,具备以下有益效果:本方案采用步进电机进行对晷面角度进行精确自动控制,晷面上的光敏电阻传感器可以检测晷针影子的位置变化,通过数码管显示当地时间,并通过转换显示当地标准时间,将对时间数字化展示,具有结构简单以及时间精准等特性。
2023-10-31T00:39:11Z
Research on piston error sensing for segmented mirrors under atmospheric turbulence
Wang B(王斌)
Jin ZY(金振宇)
Dai YC(戴懿纯)
Yang, DeHua
Xu FY(许方宇)
http://ir.ynao.ac.cn:80/handle/114a53/26352
2023-11-06T08:35:56Z
2023-10-30T06:21:58Z
题名: Research on piston error sensing for segmented mirrors under atmospheric turbulence
作者: Wang B(王斌); Jin ZY(金振宇); Dai YC(戴懿纯); Yang, DeHua; Xu FY(许方宇)
摘要: <p>Large aperture ground-based segmented telescopes typically use electrical edge sensors to detect co-phase errors. However, complex observing environments can lead to zero-point drift of the edge sensors, making it challenging to maintain the long-term co-phase of the segmented primary mirror using only edge sensors. Therefore, employing optical piston error detection methods for short-term calibration of edge sensors can address the issue of zero-point drift in the sensors. However, atmospheric turbulence can affect calibration accuracy based on the observational target. To achieve high-precision calibration of electrical edge sensors, this study investigates the impact of atmospheric turbulence on optical piston error detection. Based on simulated results, it is found that the actual measured piston error in the presence of atmospheric turbulence is the difference between the average phases of the two segments. Subsequently, optical piston error detection experiments were conducted in a segmented mirror system under simulated turbulent conditions with varying turbulence intensities. Experimental studies have shown that the detection accuracy of the optical method is almost the same as without turbulence when using a detection aperture size that is 0.82 times the atmospheric coherence length and an exposure time of at least 40 ms. The root mean square of the cross-calibration is better than 3 nm. These experimental results indicate that under conditions of good atmospheric seeing, the optical piston error detection method can meet the short-term calibration requirements of edge sensors by setting reasonable detection area size and exposure time. It may even be possible to directly use optical detection methods to replace edge sensors for real-time detection of piston errors. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement</p>
2023-10-30T06:21:58Z
The Effect of Irradiation on the Spin of Millisecond Pulsars
Lan SY(兰顺义)
Meng XC(孟祥存)
http://ir.ynao.ac.cn:80/handle/114a53/26351
2023-11-06T08:38:18Z
2023-10-30T06:20:37Z
题名: The Effect of Irradiation on the Spin of Millisecond Pulsars
作者: Lan SY(兰顺义); Meng XC(孟祥存)
摘要: <p>A millisecond pulsar (MSP) is an old neutron star (NS) that has accreted material from its companion star, causing it to spin up, which is known as the recycling scenario. During the mass transfer phase, the system manifests itself as an X-ray binary. PSR J1402+13 is an MSP with a spin period of 5.89 ms and a spin period derivative of logPspin=-16.32 . These properties make it a notable object within the pulsar population, as MSPs typically exhibit low spin period derivatives. In this paper, we aim to explain how an MSP can possess a high spin period derivative by binary evolution. By utilizing the stellar evolution code MESA, we examine the effects of irradiation on the companion star and the propeller effect on the NS during binary evolution. We demonstrate that irradiation can modify the spin period and mass of an MSP, resulting in a higher spin period derivative. These results suggest that the irradiation effect may serve as a key factor in explaining MSPs with high spin period derivatives.</p>
2023-10-30T06:20:37Z
Differential Rotation for Different-sized Sunspot Groups Early Observed by the OGAUC
Wan M(万苗)
Gao PX(高朋鑫)
Zeng, Shu-Guang
Deng LH(邓林华)
http://ir.ynao.ac.cn:80/handle/114a53/26350
2023-11-06T08:37:04Z
2023-10-30T06:20:30Z
题名: Differential Rotation for Different-sized Sunspot Groups Early Observed by the OGAUC
作者: Wan M(万苗); Gao PX(高朋鑫); Zeng, Shu-Guang; Deng LH(邓林华)
摘要: <p>Solar differential rotation is an important ingredient of the solar dynamo model, not only because the solar rotation profile is one of the key inputs in a solar dynamo model, but also because it imposes constraints for the solar dynamo model. In this study, we use the sunspot group catalog published by the Coimbra Astronomical Observatory for the period 1929-1941 to analyze solar rotation profiles of different-sized sunspot groups and the dependence of their annual average of the absolute latitude and annual average rotation rate on the solar cycle. The following main results are obtained: (1) smaller sunspot groups (with an area <100 millionths of the solar hemisphere (msh)) rotate faster than larger ones (with an area >500 msh); (2) different-sized sunspot groups drift toward the equator at different velocities of latitudinal drift, reflecting that they are rooted at different anchoring depths; (3) the rotation rate reaches a maximum during the minimum of the solar cycle, which seems to be independent of the size of sunspot groups. The possible mechanisms for the above results are discussed, and we infer that the differences may be due to the different anchoring depths at which flux tubes of different-sized sunspot groups are rooted, their different ages, and the different ways in which sunspot group coordinates are determined.</p>
2023-10-30T06:20:30Z