Abstract
Abstract
Multiplanet systems exhibit a diversity of architectures that diverge from the solar system and contribute to the topic of exoplanet demographics. Radial velocity (RV) surveys form a crucial component of exoplanet surveys, as their long observational baselines allow for searches for more distant planetary orbits. This work provides a significantly revised architecture for the multiplanet system HD 134606 using both HARPS and UCLES RVs. We confirm the presence of previously reported planets b, c, and d with periods of
12.0897
−
0.0018
+
0.0019
,
58.947
−
0.054
+
0.056
, and
958.7
−
5.9
+
6.3
days and masses of
9.14
−
0.63
+
0.65
, 11.0 ± 1, and 44.5 ± 2.9 Earth masses, respectively, with the planet d orbit significantly revised to over double that originally reported. We report two newly detected super-Earths, e and f, with periods of
4.31943
−
0.00068
+
0.00075
and
26.9
−
0.017
+
0.019
days and masses of
2.31
−
0.35
+
0.36
and
5.52
−
0.73
+
0.74
Earth masses, respectively. In addition, we identify a linear trend in the RV time series, and the cause of this acceleration is deemed to be a newly detected massive companion with a very long orbital period. HD 134606 now displays four low-mass planets in a compact region near the star, one gas giant further out in the habitable zone, an additional companion in the outer regime, and a low-mass M dwarf stellar companion at large separation, making it an intriguing target for system formation/evolution studies. The location of planet d in the habitable zone proves to be an exciting candidate for future space-based direct imaging missions, whereas continued RV observations of this system are recommended for understanding the nature of the massive, long-period companion.
Publisher
American Astronomical Society