  We analyzed the star HD 171219, one of the relatively bright Be stars
observed in the seismo field of the CoRoT satellite, in order to determine its
physical and pulsation characteristics. Classical Be stars are main-sequence
objects of mainly B-type, whose spectra show, or had shown at some epoch,
Balmer lines in emission and an infrared excess. Both characteristics are
attributed to an equatorially concentrated circumstellar disk fed by
non-periodic mass-loss episodes (outbursts). Be stars often show nonradial
pulsation gravity modes and, as more recently discovered, stochastically
excited oscillations. Applying the CLEANEST algorithm to the high-cadence and
highly photometrically precise measurements of the HD 171219 light curve led us
to perform an unprecedented detailed analysis of its nonradial pulsations. Tens
of frequencies have been detected in the object compatible with nonradial
g-modes. Additional high-resolution ground-based spectroscopic observations
were obtained at La Silla (HARPS) and Haute Provence (SOPHIE) observatories
during the month preceding CoRoT observations. Additional information was
obtained from low-resolution spectra from the BeSS database. From spectral line
fitting we determined physical parameters of the star, which is seen
equator-on. We also found in the ground data the same frequencies as in CoRoT
data. Additionally, we analyzed the circumstellar activity through the
traditional method of V/R emission H{\alpha} line variation. A quintuplet was
identified at approximately 1.113 c/d (12.88 {\mu}Hz) with a separation of
0.017 c/d that can be attributed to a pulsation degree l~2. The light curve
shows six small- to medium-scale outbursts during the CoRoT observations. The
intensity of the main frequencies varies after each outburst, suggesting a
possible correlation between the nonradial pulsations regime and the feeding of
the envelope.
