1994A&A...288..155N

We report the discovery of non-radial pusations with at least 5 periods in the B8V star HD 37151, a probable member of the Orion OB1 association. This result is based on 465 photometric maesurements in 7 colours spanning 12 years. In addition, 30 high-resolution spectra were taken in the MgII λ4481 region: they show a small projected rotational velocity and slight variations of the line profiles where at least two out of the five photometric periods can be identified. Although this star was once classified B8Vp(Si), all available data show it is a normal star instead. Therefore, this object is not another example (after ET And) of a pulsating silicon star, but entirely matches the characteristics of Waelkens' "Slowly Pulsating B stars" (SPB). It offers the interest of being the second coolest member of this class, helping to define empirically the cool border of the related instability domain. The ratio of colour to visual amplitudes A_[U–B]/A_V of the known SPB stars is nicely correlated with T_eff, in good agreement with theoretical expectations for non-radial pulsations with order l ≤2.