Endl et al. reported a Neptune-mass planet in a 10.24 day orbit around GJ 176. This planet has raised interest because of its low mass (Msin i = 24 M Earth), correspondingly small velocity amplitude (K = 11.7 m s-1), and because GJ 176 is an M star. We report 41 precise Doppler measurements of GJ 176 obtained with the Keck-HIRES spectrometer over a 10 year time span. These measurements show no evidence of the 10.24 day companion, at a threshold of 4 m s-1, a factor of 3 less than the amplitude reported by Endl et al. The Keck velocities are consistent with instrumental noise and stellar jitter. The existence of the planet is thus called into question.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science