相关论文: Two Egyptian Kings, Shepseskaf and Userkaf, and a …

The transit of Mercury occurred two times in this century: 2003, May 7 and 2006, November 8. In 2016 there is another opportunity to observe this phenomenon and measure the solar diameter with the method of comparing the ephemerides with…

This work analyzes the phase correlation of the three lunar cycles and the Saros/Exeligmos cycle, after the study of the chapter About Exeligmos in Introduction to the Phenomena by Geminus. Geminus, refers that each Exeligmos cycle began on…

With no firm evidence for life beyond our solar system, inferences about the population observers such as ourselves rests upon the Earth as a single input, at least for now. Whilst the narrative of our home as a 'humdrum' system has become…

A rare eclipse of the mysterious object Epsilon Aurigae will occur in 2009-2011. We report an updated single-lined spectroscopic solution for the orbit of the primary star based on 20 years of monitoring at the CfA, combined with historical…

The official Iranian calendar is a solar one that in both the length and the first day of its year is based not on convention, but on two natural (i.e. astronomical) factors: a) the moment of coincidence of the centre of the Sun and the…

We report a long-term (1961-2017) study of the eclipse times in the dwarf nova WZ Sagittae, in an effort to learn its rate of orbital-period change. Some wiggles with a time scale of 20-50 years are apparent, and a connection with the…

The mysterious lines in the desert of Nazca in southern Peru received many attempts at an explanation. We discuss the possibility that their origin is based on solar eclipses which could have evoked some kind of "reaction" by the…

We present the result of the survey of sunspots and auroras in ${\it Q\bar{\imath}ngsh\check{\imath}ga\check{o}}$, the draft chronicle of ${\it Q\bar{\imath}ng}$ dynasty, for the period of 1559-1912 CE, as a sequel of the series of works…

Egypt faced heavy rainfall starting from 26th October 2016 which caused flooding in Upper Egypt and Red Sea Coast especially the city of Ras Gharib. In this work, Weather Research and Forecasting (WRF) model was used with one domain of…

CW Mon is a relatively bright and nearby SS Cyg-type dwarf nova frequently used in detailed analysis of cataclysmic variables and statistical studies. Using Transiting Exoplanet Survey Satellite (TESS) observations, we found that the…

1ES 1927+654 is an active galactic nucleus (AGN) that appears to defy the unification model. It exhibits a type-2 optical spectrum, but possesses little X-ray obscuration. XMM-Newton and Suzaku observations obtained in 2011 are used to…

We report on the validation and characterisation of two transiting planets around TOI-1453, a K-dwarf star in the TESS northern continuous viewing zone. In addition to the TESS data, we used ground-based photometric, spectroscopic, and…

We report the discovery of a super-Earth and a sub-Neptune transiting the star HD 15337 (TOI-402, TIC 120896927), a bright (V=9) K1 dwarf observed by the Transiting Exoplanet Survey Satellite (TESS) in Sectors 3 and 4. We combine the TESS…

We present Keck/NIRC2 and OSIRIS near-infrared imaging and spectroscopy of 2M0441+2301 AabBab, a young (1--3 Myr) hierarchical quadruple system comprising a low-mass star, two brown dwarfs, and a planetary-mass companion in Taurus. All four…

We investigate the plausible history of the XUV luminosity evolution of the planet-hosting M4 star GJ 1132 (~0.2 solar masses) to infer the cumulative incident XUV flux intercepted by the short-period (~1.6 d) Earth-sized transiting planet…

We present the XMM-Newton observations obtained during four revolutions in Spring and Summer 2004 of CXOGC J174540.0-290031, a moderately bright transient X-ray source, located at only 2.9" from SgrA*. We report the discovery of sharp and…

The year 2012 will be the fourth centennial year of the Jesuit Christopher Clavius (1535-1612), known as the Euclid of XVI century and the collaborator of the Pope Gregory XIII for the calendar reformation. In the occasion of the year of…

We present a general description of the Iranian calendar and Nowruz, which starts at the precise instant when the Sun coincides with the vernal equinox. Although the paper aims at the basic astronomical elements of the calendar, historical…

We present a multiwavelength study of the highly evolved compact galaxy group known as Seyfert's Sextet (HCG79: SS). We interpret SS as a 2-3 Gyr more evolved analog of Stephan's Quintet (HCG92: SQ). We postulate that SS formed by…

We take advantage of more than 10 years of monitoring of the eclipsing HMXB systems LMC X-4, Cen X-3, 4U 1700-377, 4U 1538-522, SMC X-1, IGR J18027-2016, Vela X-1, IGR J17252-3616, XTE J1855-026, and OAO 1657-415 with the ASM on-board RXTE…