Context : Herbig Ae/Be stars are intermediate-mass pre-main sequence ( PMS ) stars showing signs of intense activity and strong stellar winds , whose origin is not yet understood in the frame of current theoretical models of stellar evolution for young stars .
The evolutionary tracks of the earlier Herbig Ae stars cross for a significant fraction of their evolution towards the main sequence the theoretical PMS instability strip located roughly in the same area of the HR diagram as the \delta Scuti variables .
Many of these stars exhibit pulsations of \delta Scuti type .

Aims : We carry out a thorough analysis of the line profile variations of the pulsating prototype Herbig Ae star HD 104237 based on high-resolution spectroscopical time-series , identifiy the dominant non-radial pulsation mode , and perform the most accurate determination of its fundamental parameters in preparation of an asteroseismic modeling .

Methods : HD 104237 is a pulsating Herbig Ae star with eight detected frequencies based on the analysis of radial velocity variations .
In this article , we reinvestigated an extensive high-resolution quasi-continuous spectroscopic data set in order to search for very faint indications of non-radial pulsations in the line profile .
To do this , we worked on dynamical spectra of equivalent photospheric ( LSD ) profiles of HD 104237 .
A 2D Fourier analysis ( F2D ) was performed of the entire profile and enabled the identification of the dominant non-radial pulsating mode .
The temporal variation of the central depth of the line was studied with the time-series analysis tools Period04 and SigSpec .
The development of a highly accurate continuum normalization method enabled us to determine reliably the equivalent width of chosen absorption lines and to perform a new determination of the fundamental stellar parameters .

Results : Following the previous studies on this star , our analysis of the dynamical spectrum of recentered LSD profiles corresponding to the 22 ^ { nd } -25 ^ { th } of April 1999 nights spectra has confirmed the presence of multiple oscillation modes of low-degree \ell in HD 104237 and led to the first direct detection of a non-radial pulsation mode in this star : the dominant mode F 1 was identified by the Fourier 2D method having a degree \ell value comprised between 1 and 2 , the symmetry of the pattern variation indicating an azimuthal order of \pm 1 .
The detailed study of the fundamental stellar parameters has provided a T _ { eff } , log g and iron abundance of 8550 \pm 150 K , 3.9 \pm 0.3 and -4.38 \pm 0.19 ( i.e .
[ Fe/H ] = +0.16 \pm 0.19 ) , respectively .

Conclusions :