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Hossein Dehghan

Publications and source records attributed to Hossein Dehghan.

7 recordsLinked to original sources
arXiv2026

Detailed TESS-Based Light Curve Modeling and Fundamental Parameter Estimation of 27 W UMa-Type Contact Binaries

We performed a comprehensive analysis of 27 short period contact binary systems for which no light curve analysis had previously been reported. Photometric time-series data from the TESS mission were used in this analysis. The observational results were validated using additional TESS sectors, along with complementary photometric observations from the ASAS-SN survey. The photometric light curves of the 27 contact binary systems were analyzed with the BSN application. Model solutions were obtained through iterative fitting followed by MCMC-based refinement to derive reliable system parameters, and starspot configurations were incorporated for seven targets exhibiting O'Connell effect asymmetries. The absolute parameters of the target systems were derived using the empirical parameter relationship between orbital period and semi-major axis. Based on the results of the light curve solutions and the estimated absolute parameters, five of the analyzed systems are identified as A-subtype, while the remaining targets belong to the W-subtype. We analyzed a sample of 484 W UMa contact binaries to identify the physical and orbital parameters that most effectively distinguish A-subtype from W-subtype systems using t-statistics. Three targets exhibited extremely low mass ratios, and their orbital analysis confirmed that they are dynamically stable. The evolutionary states of the systems were examined, showing that lower-mass companions are generally more evolved, while more massive components remain less evolved. The positions of the systems and their stellar components were compared across four diagrams derived from empirical parameter relationship studies, showing good agreement with the linear fits.

astro-ph.SR↗
arXiv2015

Characterizing of Inner Product Spaces by the Mapping $n_{x,y}$

For the vectors $x$ and $y$ in a normed linear spaces $X$, the mapping $n_{x,y}: \mathbb{R}\to \mathbb{R}$ is defined by $n_{x,y}(t)=\|x+ty\|$. In this note, comparing the mappings $n_{x,y}$ and $n_{y,x}$ we obtain a simple and useful characterization of inner product spaces.

math.FA↗
arXiv2013

Some Monotonicity Properties of Convex Functions with Applications

We mainly establish a monotonicity property between some special Riemann sums of a convex function $f$ on $[a,b]$, which in particular yields that $\frac{b-a}{n+1}\sum_{i=0}^n f\left(a+i\frac{b-a}{n}\right)$ is decreasing while $\frac{b-a}{n-1}\sum_{i=1}^{n-1} f\left(a+i\frac{b-a}{n}\right)$ is an increasing sequence. These give us a new refinement of the Hermitt-Hadamard inequality. Moreover, we give a refinement of the classical Alzer's inequality together with a suitable converse to it. Applications regarding to some important convex functions are also included.

math.CA↗