Context : The object HD 43587Aa is a G0V star observed during the 145-day LRa03 run of the COnvection , ROtation and planetary Transits space mission ( CoRoT ) , for which complementary High Accuracy Radial velocity Planet Searcher ( HARPS ) spectra with S/N > 300 were also obtained .
Its visual magnitude is 5.71 , and its effective temperature is close to 5950 K. It has a known companion in a highly eccentric orbit and is also coupled with two more distant companions .

Aims : We undertake a preliminary investigation of the internal structure of HD 43587Aa .

Methods : We carried out a seismic analysis of the star , using maximum likelihood estimators and Markov Chain Monte Carlo methods .

Results : We established the first table of the eigenmode frequencies , widths , and heights for HD 43587Aa .
The star appears to have a mass and a radius slightly larger than the Sun , and is slightly older ( 5.6 Gyr ) .
Two scenarios are suggested for the geometry of the star : either its inclination angle is very low , or the rotation velocity of the star is very low .

Conclusions : A more detailed study of the rotation and of the magnetic and chromospheric activity for this star is needed , and will be the subject of a further study .
New high resolution spectrometric observations should be performed for at least several months in duration .