[Tex/LaTex] Problem with \corref instruction in elsarticle document class

Question

In the following TeX file which is written based on elsarticle template, I want the second author (author2) be the corresponding author. I put the \corref instruction for author2 but when I run the code, the \ast symbol appears for both author2 and author3.

\documentclass[preprint,12pt]{elsarticle}
\usepackage{epsfig}
\usepackage{subcaption}
\captionsetup{compatibility=false}
%% The amssymb package provides various useful mathematical symbols
\usepackage{amssymb}
\usepackage{mathptmx} 
\usepackage{amsmath}
\newtheorem{thm}{Theorem}
\newproof{pf}{Proof}
\DeclareMathOperator*{\argmin}{arg\,min}
\DeclareMathOperator{\sign}{sign}
\journal{X}

\begin{document}

\begin{frontmatter}

\title{The title of the paper are placed here}


\author{author1}
\ead{author1\_ family@yahoo.com}

\author{author2\corref{cor}}
\ead{author2@yahoo.com}

\author{author3}
\ead{author3@yahoo.com}

\address{The affiliations and adresses}
\cortext[cor]{Corresponding author}

\begin{abstract}
%% Text of abstract
Some text are presented here.
\end{abstract}

\begin{keyword}
%% keywords here, in the form: keyword \sep keyword
Keyword1 \sep Keyword2 \sep Keyword3

\end{keyword}

\end{frontmatter}

\section{Introduction}
\label{intro}
Introduction goes here.

\bibliographystyle{elsarticle-num} 
\bibliography{Bibiliography}
\end{document}

Answer 1

In my opinion, this is a bug in elsarticle. If you have three authors with the same address, you can work around the bug by an empty \corref statement.

\documentclass[preprint,12pt]{elsarticle}
\usepackage{amssymb}
\usepackage{amsmath}

\usepackage{graphicx}
\usepackage{subcaption}

\newtheorem{thm}{Theorem}
\newproof{pf}{Proof}
\DeclareMathOperator*{\argmin}{arg\,min}
\DeclareMathOperator{\sign}{sign}
\journal{X}

\begin{document}

\begin{frontmatter}

\title{The title of the paper are placed here}

\author{author1}
\ead{author1\_family@yahoo.com}

\author{author2\corref{cor}}
\ead{author2@yahoo.com}

\author{author3\corref{}}
\ead{author3@yahoo.com}

\address{The affiliations and addresses}

\cortext[cor]{Corresponding author}

\begin{abstract}
%% Text of abstract
Some text are presented here.
\end{abstract}

\begin{keyword}
%% keywords here, in the form: keyword \sep keyword
Keyword1 \sep Keyword2 \sep Keyword3

\end{keyword}

\end{frontmatter}

\section{Introduction}
\label{intro}
Introduction goes here.

\bibliographystyle{elsarticle-num} 
\bibliography{Bibiliography}
\end{document}

A few notes. The package epsfig only exists for compatibility with older (pre 1992) documents and should not be used in newer documents. The right package to use is graphicx. There's no reason for the compatibility=false option to caption. Instead of mathptmx you should consider

\usepackage{newtxtext,newtxmath}