The Three-Dimensional Orbit and Physical Parameters of 47 Oph

Abstract

Although 47 Oph has been shown to be a binary with a period of ∼27 days using both spectroscopic and interferometric techniques, only a preliminary orbit has been obtained in the previous work due to the shortage of high precision measurements. Since 1997, new spectroscopic and interferometric measurements have been obtained with much higher precision by the spectrograph of the 2.16 m telescope at Xinglong station and the Navy Precision Optical Interferometer, respectively. Combining all of the measurements, a three-dimensional orbit is obtained with high precision in this work. Thus, the component masses are calculated to be 1.50 ± 0.06 and 1.34 ± 0.06  M , respectively. The orbital parallax is 32.6 ± 0.6 mas, which is consistent with the Hipparcos parallax. With the known apparent magnitudes and color indices of the components, the derived luminosities are 7.80 ± 0.36 and 3.41 ± 0.25  L. The estimated radii of the components are 2.06 ± 0.07 and 1.36 ± 0.06  R. Finally, the evolutionary status of the components are investigated with the help of a stellar evolution model.

The California-Kepler Survey. VIII. Eccentricities of Kepler Planets and Tentative Evidence of a High-metallicity Preference for Small Eccentric Planets

“…High stellar mass is associated with more massive disks (Andrews et al 2013), which may encourage giant planet formation (Kennedy & Kenyon 2008), but also decreased lifetimes which may inhibit it (Ribas et al 2015). However, high metallicity environments promote both more robust planet formation and longer disc lifetimes increasing both the frequency of giant planets (Yasui et al 2010;Ercolano & Clarke 2010) and perhaps Earth to sub-Saturn planets (Wang & Fischer 2015;Petigura et al 2018, but c.f. Buchhave & Latham 2015).…”

The Boundary between Gas-rich and Gas-poor Planets

“…The wide range of possible origins for sub-Neptunes may be the reason why their occurrence rates do not correlate strongly with the host star metallicity. Numerous studies report a strong correlation between the stellar metallicity and the occurrence rate of Jupiters (e.g., Fischer & Valenti 2005) and sub-Saturns (e.g., Petigura et al 2018) but considerably weaker correlation for smaller sub-Neptunes (e.g., Buchhave et al 2014;Wang & Fischer 2015). It is likely that metal-rich stars harbored solid-heavy disks that carry the potential of creating more massive cores.…”

“…Another feature of the pebble isolation mass is that it does not depend on the solid mass reservoir (as long as the disk contains enough solids to create cores of pebble isolation mass). It is unlikely that the final planetary cores of inner Kepler planets are set by pebble isolation, as it is difficult to reconcile with the observed correlation between stellar metallicity and the planet occurrence rate (Wang & Fischer 2015;Petigura et al 2018; Owen & Murray-Clay 2018 but see Wu 2018 for an opposing view). Furthermore, pebble isolation mass rises steeply with orbital distance (M peb,iso ∝ a 6/7 for our choice of temperature profile), with no other stronger dependence on either the disk property or the stellar mass.…”

A Joint Mass–Radius–Period Distribution of Exoplanets

“…There are also a variety of factors associated with the host star that can affect planet occurrence. Host star metallicity has shown to have a significant effect not only on gas giant occurrence rates, but also sub-Neptune and terrestrial planets, with higher metallicities associated with higher planet occurrence (Wang & Fischer 2015;Mulders et al 2016;Dong et al 2018;Petigura et al 2018). The presence of stellar companions has been linked to lower occurrence rates (Wang et al 2014;Kraus et al 2016 Figure 8.…”