Changes of Period in Variable Stars of Long Period

evaluation of sadr eminence in safavid period

چکیده: یکی از دوره های مهم تاریخی ایران به لحاظ تأمین استقلال ملی مذهبی و حتی تأثیر آن بر فرهنگ و مذهب ایرانیان، دوره صفویه است. رسمیت دادن و رواج مذهب شیعه توسط شاه اسماعیل اول، یکی از مهمترین اقدامات این دولت محسوب می شود. بنابراین برای اجرای این سیاست، وی منصب صدارت را به عنوان منصبی مذهبی- حکو متی ایجاد کرد .این منصب از دوره ی تیموریان ایجاد شده بود ولی در اواخر این دوره اهمیت بیشتری یافت...

Envelope tomography of long - period variable stars ⋆

This paper is the first one in a series devoted to the study of the dynamics of the atmospheres of longperiod variable (LPV) stars. Results from a two-monthlong monitoring of the Mira variables RTCyg and XOph around maximum light with the ELODIE spectrograph at the Haute-Provence Observatory are presented. The monitoring covers phases 0.80 to 1.16 for RTCyg and phases 0.83 to 1.04 for XOph. The...

prediction of ignition delay period in d.i diesel engines

a semi-empirical mathematical model for predicting physical part of ignition delay period in the combustion of direct - injection diesel engines with swirl is developed . this model based on a single droplet evaporation model . the governing equations , namely , equations of droplet motion , heat and mass transfer were solved simultaneously using a rung-kutta step by step unmerical method . the...

Tomography of the atmosphere of long-period variable stars

This paper reviews the results obtained so far with the newly developed tomographic technique, which probes the velocity field across the atmosphere of long-period variable (LPV) stars. The method cross-correlates the optical spectrum with numerical masks constructed from synthetic spectra and probing layers of increasing depths. This technique reveals that the line doubling often observed in L...

The Absolute Magnitudes of Long Period Variable Stars.