Abstract
Abstract We present high-resolution speckle interferometric imaging observations of TESS exoplanet host stars using the NN-EXPLORE Exoplanet and Stellar Speckle Imager instrument at the 3.5 m WIYN telescope. Eight TESS objects of interest that were originally discovered by Kepler were previously observed using the Differential Speckle Survey Instrument. Speckle observations of 186 TESS stars were carried out, and 45 (24%) likely bound companions were detected. This is approximately the number of companions we would expect to observe given the established 46% binarity rate in exoplanet host stars. For the detected binaries, the distribution of stellar mass ratio is consistent with that of the standard Raghavan distribution and may show a decrease in high-q systems as the binary separation increases. The distribution of binary orbital periods, however, is not consistent with the standard Ragahavan model, and our observations support the premise that exoplanet-hosting stars with binary companions have, in general, wider orbital separations than field binaries. We find that exoplanet-hosting binary star systems show a distribution peaking near 100 au, higher than the 40–50 au peak that is observed for field binaries. This fact led to earlier suggestions that planet formation is suppressed in close binaries.
Highlights
Our team has been carrying out high-resolution speckle imaging of stars for which transit-like signals have been detected by the planet-finding missions Kepler (Borucki et al 2011), K2 (Howell et al 2014), and TESS (Ricker et al 2015)
Speckle observations presented in this paper were accomplished using the NN-EXPLORE Exoplanet and Stellar Speckle Imager (NESSI) high-resolution speckle imaging instrument (Scott et al 2018) mounted on the 3.5 m WIYN telescope located at Kitt Peak National Observatory
While the resolution of speckle imaging does not decrease with bad seeing, spreading the light out over a larger area both decreases the correlation of individual speckles across the image and makes individual speckles harder to detect above any background sky noise during the 40 ms observation time
Summary
Our team has been carrying out high-resolution speckle imaging of stars for which transit-like signals have been detected by the planet-finding missions Kepler (Borucki et al 2011), K2 (Howell et al 2014), and TESS (Ricker et al 2015). The signal of a deep eclipse, when combined with the constant light from the target star, may mimic an exoplanet-like signal This and other stellar configurations can be troublesome (Brown et al 2011), requiring follow-up observations to confirm or validate transiting planets. Other studies find fewer close binary companions around Kepler exoplanet host stars (Kraus et al 2016) and TESS planet candidate host stars (Ziegler et al 2020). Matson et al (2018) identified exoplanet candidate host stars from K2 that have stellar companions within 40 au based on the projected separation of the detected companion and the estimated distance to the system To date, it has remained unclear if close binaries are able to host exoplanets and whether the formation and survival of a planetary system is possible under such conditions. We present the results of our first year of TESS high-resolution speckle imaging follow-up using the NN-EXPLORE Exoplanet and Stellar Speckle Imager (NESSI) instrument at the WIYN 3.5 m telescope
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
