UvA-DARE ( Digital Academic Repository ) Solar-like oscillations in the G 8 V star τ Ceti

We used HARPS to measure oscillations in the low-mass star τ Cet. Although the data were compromised by instrumental noi se, we have been able to extract the main features of the oscillatio ns. We foundτ Cet to oscillate with an amplitude that is about half that of the Sun, and with a mode lifetime that is slightly shorter tha n solar. The large frequency separation is 169 μHz, and we have identified modes with degrees 0, 1, 2, and 3. We used the frequencies to es timate the mean density of the star to an accuracy of 0.45% whi ch, combined with the interferometric radius, gives a mass of 0 .783± 0.012M⊙ (1.6%).