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 ( i = 90 ^ { \circ } ) .
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 violet to red emission H \alpha line variation .
A quintuplet was identified at approximately 1.113 c d ^ { -1 } ( 12.88 \mu Hz ) with a separation of 0.017 c d ^ { -1 } that can be attributed to a pulsation degree \ell \sim 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 .