  We study the event shape variables, transverse energy energy correlation TEEC
$(\cos \phi)$ and its asymmetry ATEEC $(\cos \phi)$ in deep inelastic
scattering (DIS) at the electron-proton collider HERA, where $\phi$ is the
angle between two jets defined using a transverse-momentum $(k_T)$ jet
algorithm. At HERA, jets are defined in the Breit frame, and the leading
nontrivial transverse energy energy correlations arise from the 3-jet
configurations. With the help of the NLOJET++, these functions are calculated
in the leading order (LO) and the next-to-leading order (NLO) approximations in
QCD at the electron-proton center-of-mass energy $\sqrt{s}=314$ GeV. We
restrict the angular region to $-0.8 \leq \cos \phi \leq 0.8$, as the forward-
and backward-angular regions require resummed logarithmic corrections, which we
have neglected in this work. Following experimental jet-analysis at HERA, we
restrict the DIS-variables $x$, $y=Q^2/(x s)$, where $Q^2=-q^2$ is the negative
of the momentum transfer squared $q^2$, to $0 \leq x \leq 1$, $0.2 \leq y \leq
0.6$, and the pseudo-rapidity variable in the laboratory frame $(\eta^{\rm
{lab}})$ to the range $-1 \leq \eta^{\rm {lab}} \leq 2.5$. The TEEC and ATEEC
functions are worked out for two ranges in $Q^2$, defined by $5.5~{\rm GeV}^2
\leq Q^2 \leq 80~{\rm GeV}^2$, called the low-$Q^2$-range, and $150~{\rm GeV}^2
\leq Q^2 \leq 1000~{\rm GeV}^2$, called the high-$Q^2$-range. We show the
sensitivity of these functions on the parton distribution functions (PDFs), the
factorization $(\mu_F)$ and renormalization $(\mu_R)$ scales, and on
$\alpha_s(M_Z)$. Of these the correlations are stable against varying the scale
$\mu_F$ and the PDFs, but they do depend on $\mu_R$. These studies are useful
in the analysis of the HERA data, including the determination of
$\alpha_s(M_Z)$ from the shape variables.
