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Propagation of Solar disturbances in the heliosphere to a distance of 100 au
Akasofu, Syun-Ichi
Explosive solar activities cause heliospheric disturbances. A simple scheme of simulating the propagation of shock waves in the heliosphere is devised to study such disturbances caused by solar flares. This scheme, the HAF scheme, is capable of simulating the propagation of many shock waves generated during extended periods up to a distance of 100…
L1 and Off Sun-Earth Line Visible-Light Imaging of Earth-Directed CMEs: An Analysis of Inconsistent Observations
Möstl, Christian; Barnes, David; Davies, Jackie A. +1 more
The efficacy of coronal mass ejection (CME) observations as a key input to space weather forecasting is explored by comparing on and off Sun-Earth line observations from the ESA/NASA SOHO and NASA STEREO spacecraft. A comparison is made of CME catalogs based on L1 coronagraph imagery and off Sun-Earth line coronagraph and heliospheric imager obser…
Nötron Yıldızı ve Karadelik İçeren Düşük Kütleli X-ışın çiftlerinin Düşük Işımagücü Bölgesindeki Davranışlarının Karakterizasyonu
Genç, Yakup; Sonbaş, Eda
X-ışın çiftlerinin taç bölgesinin doğası ve Compton saçılmasının kritik bileşeni olan düşük enerjili fotoların temelini oluşturan geometrik yapısı ile ilgili araştırmalar son yıllarda büyük ivme kazanmıştır. Bu nedenle bileşenlerinden biri Nötron Yıldız (NY) veya Kara delik (KD) olan sistemlerin özellikle düşük ışımagücü ($\lesssim10^{35}$ erg s$^…
A photodissociation region (PDR) model grid in planetary nebula paradigm: dependency of C and O fine structure line emission and PDR thermal structure on central star radiation and nebular dust composition
Das, Ramkrishna; Bandyopadhyay, Rahul
We compute a grid of photodissociation region (PDR) models. The varying parameters of the grid include effective temperature (Teff) and luminosity (L) of the radiation source, density (nH) of the nebula, PDR depth from the nebular ionization front (ΔrPDR), and densities of polycyclic aromatic hydrocarbon (PAH) mole…
Variable stars in the field of open cluster NGC 6819
Karimov, R. G.; Gaysin, R. A.
Here we present preliminary results of searching and study of variable stars based on space observation data of the TESS mission in the field of the open star cluster NGC 6819. The light curves of variable stars of various types located in the field of an open cluster are studied. Based on the data from the GAIA DR3 mission, the probable members o…
Variation of temperature and non-thermal velocity with height in fan loops
Tripathi, Durgesh; Sharma, Aishawnnya
We study the variation of temperature and non-thermal velocity with height in fan loops. For this purpose, we have used the observations recorded by the Extreme Ultraviolet Imaging Spectrometer onboard Hinode. We have employed the emission measure (EM)-loci method to estimate the temperatures of different coronal fan loops and then compute the non…