What are solar-like oscillations?
Oscillations in the Sun are excited stochastically by convection. We use the term “solarlike” to refer to oscillations in other stars that are excited by the same mechanism, even though some of these stars may be very different from the Sun. The stochastic nature of the excitation produces oscillations over a broad range of frequencies, which in the Sun is about 1 to 4mHz (the well-known 5-minute oscillations). Stellar oscillations can also be excited via opacity variations (the heat-engine mechanism, also called the k mechanism), as seen in various types of classical pulsating stars (Cepheids, RR Lyraes, Miras, white dwarfs, δ Scuti stars, etc.).
For a star to show solar-like oscillations, it must be cool enough to have a surface convective zone. In practice, this means being cooler than the red edge of the classical instability strip, which includes the lower main sequence, as well as cool subgiants and even red giants. Indeed, solar-like oscillations with periods of hours (and longer) have now been observed in thousands of G and K giants (see Section 3.9). There is also good evidence that the pulsations in semiregular variables (M giants) are solar-like (Christensen-Dalsgaard et al., 2001; Bedding, 2003; Tabur et al., 2010), as perhaps are those in M supergiants such as Betelgeuse (Kiss et al., 2006).
What about hotter stars? By definition, solar-like oscillations are excited stochastically in the outer convection zone.