The Doppler wobble induced by the extra-solar planet HD 134987b was first detected by data from the Keck Telescope nearly a decade ago , and was subsequently confirmed by data from the Anglo-Australian Telescope .
However , as more data have been acquired for this star over the years since , the quality of a single Keplerian fit to that data has been getting steadily worse .
The best fit single Keplerian to the 138 Keck and AAT observations now in hand has an root-mean-square ( RMS ) scatter of 6.6 m/s .
This is significantly in excess of both the instrumental precision achieved by both the Keck and Anglo-Australian Planet Searches for stars of this magnitude , and of the jitter expected for a star with the properties of HD134987 .
However , a double Keplerian ( i.e .
dual planet ) fit delivers a significantly reduced RMS of 3.3 m/s .
The best-fit double planet solution has minimum planet masses of 1.59 and 0.82 1.59 \pm 0.02 M _ { Jup } , orbital periods of 258 and 5000 d , and eccentricities of 0.23 and 0.12 respectively .
We find evidence that activity-induced jitter is a significant factor in our fits and do not find evidence for asteroseismological p-modes .
We also present seven years of photometry at a typical precision of 0.003 mag with the T8 0.8 m automatic photometric telescope at Fairborn observatory .
These observations do not detect photometric variability and support the inference that the detected radial-velocity periods are due to planetary mass companions rather than due to photospheric spots and plages .