Stellar flare is one of the most challenging problems in Astrophysics. Up to now, most of the detected flare stars are of the late spectral type (e.g. UV Ceti type stars etc.). The non-classical flare stars with early...Stellar flare is one of the most challenging problems in Astrophysics. Up to now, most of the detected flare stars are of the late spectral type (e.g. UV Ceti type stars etc.). The non-classical flare stars with early spectral type are very rare, In 1975, Kunkel collected a few possible early type flare stars in his review paper, all of which had emission line spectra (W.E.Kunkal, 1975). They are many orders of magnitude more powerful than dMe flares. The nature of this kind of flare stars are unknown.Recently, a later A-type flare star BD+47 819, near the open cluster a Persei, was discovered by Jun-jie Wang. The V magnitude of the star was 9.25, ans B-V = 0.413(Prosser, 1992). Its spectral type was A7 in CSI catalog of Strasbourg (1979), and A5 in Fehrenbach’s list(Fehrenbach, 1987).BD+47 819 will be taken a special interest to be recgnized, not only for lack of knowledge on the nature of all the early type flare stars, but also as it is a peculiar A-5 type variable with flare activity. From its展开更多
In this article,we report a few advances in the studies based on the solar vector magnetic field observations which were carried out mainly with the Solar Magnetic Field Telescope at the Huairou Solar Observing Statio...In this article,we report a few advances in the studies based on the solar vector magnetic field observations which were carried out mainly with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station in the 1990s.(1) We developed necessary methodology and concepts in vector magnetogram analysis(Wang et al.1996).For the first time,we proposed to use the photospheric free magnetic energy to quantify the major flare productivity of solar active regions(ARs),and it had been proved to be the best parameter in representing the major flare activity.(2) We revealed that there was always a dominant sense of magnetic shear in a given AR(Wang 1994),which was taken as the premise of the helicity calculation in ARs;we made the first quantitative estimation of magnetic helicity evolution in ARs(Wang 1996).(3) We identified the first group of evidence of magnetic reconnection in the lower solar atmosphere with vector magnetic field observations and proposed a two-step reconnection flare model to interpret the observed association of flux cancellation and flares(Wang and Shi 1993).Efforts to quantify the major flare productivity of super active regions with vector magnetic field observations have been also taken.展开更多
Severe solar events manifested by highly energetic X-Ray events accompanied by coronal mass ejections and proton flares caused flash floods in Makkah AI-Mukaramab, A1-Madinah AI-Munawarah and Jeddah. The responses can...Severe solar events manifested by highly energetic X-Ray events accompanied by coronal mass ejections and proton flares caused flash floods in Makkah AI-Mukaramab, A1-Madinah AI-Munawarah and Jeddah. The responses can be prompt, delayed or prompt-delayed, suggesting that the protons entered the troposphere either through the opening of a direct gate in the magnetosphere to the location concer.led due to magnetic reconnection, through the polar gates or through those two paths respectively. The authors suggest that there is a magnetic anomaly in Makkah AI-Mukaramah area which makes it liable to be subjected to flash floods. The width of the solar streams determines the width of the gate opened in the magnetosphere via magnetic reconnection and thus narrow streams affect only one location of the three cities while extended width streams can cause flash floods in all of Makkah AI-Mukaramah AI-Madinah AI Munawarah and Jeddah. In addition, the November 24-26 Jeddah flash flood could be attributed to a prompt event due to a moderately fast solar stream that arrived the earth on those days.展开更多
In this paper, the relative phase relationship between flare index and sunspot activity （sunspot numbers and sunspot areas） is investigated. It is found that （i） the flare index and sunspot activity are asynchrono...In this paper, the relative phase relationship between flare index and sunspot activity （sunspot numbers and sunspot areas） is investigated. It is found that （i） the flare index and sunspot activity are asynchronous in phase space at all period scales, and the former lags behind the latter, which implies our results are supported for the integral response model; （ii） their different definitions and physical meanings may be a major reason for their phase asynchrony between them, and the solar flare activity favor to be related to the magnetic complex rather than magnetic strength.展开更多
文摘Stellar flare is one of the most challenging problems in Astrophysics. Up to now, most of the detected flare stars are of the late spectral type (e.g. UV Ceti type stars etc.). The non-classical flare stars with early spectral type are very rare, In 1975, Kunkel collected a few possible early type flare stars in his review paper, all of which had emission line spectra (W.E.Kunkal, 1975). They are many orders of magnitude more powerful than dMe flares. The nature of this kind of flare stars are unknown.Recently, a later A-type flare star BD+47 819, near the open cluster a Persei, was discovered by Jun-jie Wang. The V magnitude of the star was 9.25, ans B-V = 0.413(Prosser, 1992). Its spectral type was A7 in CSI catalog of Strasbourg (1979), and A5 in Fehrenbach’s list(Fehrenbach, 1987).BD+47 819 will be taken a special interest to be recgnized, not only for lack of knowledge on the nature of all the early type flare stars, but also as it is a peculiar A-5 type variable with flare activity. From its
文摘In this article,we report a few advances in the studies based on the solar vector magnetic field observations which were carried out mainly with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station in the 1990s.(1) We developed necessary methodology and concepts in vector magnetogram analysis(Wang et al.1996).For the first time,we proposed to use the photospheric free magnetic energy to quantify the major flare productivity of solar active regions(ARs),and it had been proved to be the best parameter in representing the major flare activity.(2) We revealed that there was always a dominant sense of magnetic shear in a given AR(Wang 1994),which was taken as the premise of the helicity calculation in ARs;we made the first quantitative estimation of magnetic helicity evolution in ARs(Wang 1996).(3) We identified the first group of evidence of magnetic reconnection in the lower solar atmosphere with vector magnetic field observations and proposed a two-step reconnection flare model to interpret the observed association of flux cancellation and flares(Wang and Shi 1993).Efforts to quantify the major flare productivity of super active regions with vector magnetic field observations have been also taken.
文摘Severe solar events manifested by highly energetic X-Ray events accompanied by coronal mass ejections and proton flares caused flash floods in Makkah AI-Mukaramab, A1-Madinah AI-Munawarah and Jeddah. The responses can be prompt, delayed or prompt-delayed, suggesting that the protons entered the troposphere either through the opening of a direct gate in the magnetosphere to the location concer.led due to magnetic reconnection, through the polar gates or through those two paths respectively. The authors suggest that there is a magnetic anomaly in Makkah AI-Mukaramah area which makes it liable to be subjected to flash floods. The width of the solar streams determines the width of the gate opened in the magnetosphere via magnetic reconnection and thus narrow streams affect only one location of the three cities while extended width streams can cause flash floods in all of Makkah AI-Mukaramah AI-Madinah AI Munawarah and Jeddah. In addition, the November 24-26 Jeddah flash flood could be attributed to a prompt event due to a moderately fast solar stream that arrived the earth on those days.
基金supported by the National Natural Science Foundation of China(Grant Nos.11003041 and 11203006)Shandong Provincial Natural Science Foundation(Grant Nos.ZR2009AM021,ZR2012AQ029,ZR2012AM008 and ZR2010AL025)+1 种基金Dezhou University Foundation(Grant No.402126)supported by Open Research Program of Key Laboratory for the Structure and Evolution of Celestial Objects,Chinese Academy of Sciences(Grant No.OP201102)
文摘In this paper, the relative phase relationship between flare index and sunspot activity （sunspot numbers and sunspot areas） is investigated. It is found that （i） the flare index and sunspot activity are asynchronous in phase space at all period scales, and the former lags behind the latter, which implies our results are supported for the integral response model; （ii） their different definitions and physical meanings may be a major reason for their phase asynchrony between them, and the solar flare activity favor to be related to the magnetic complex rather than magnetic strength.
