The Young Suns Exoplanet Survey: Detection of a wide-orbit planetary-mass companion to a solar-type Sco-Cen member

A J Bohn,M A Kenworthy,M Reggiani,J De Boer,C F Manara,C Ginski,K O Todorov,T Meshkat,C U Keller,F Snik,E E Mamajek,M J Pecaut

doi:10.1093/mnras/stz3462

Abstract

ABSTRACT The Young Suns Exoplanet Survey consists of a homogeneous sample of 70 young, solar-mass stars located in the Lower Centaurus-Crux subgroup of the Scorpius-Centaurus association with an average age of 15 ± 3 Myr. We report the detection of a co-moving companion around the K3IV star TYC 8998-760-1 (2MASSJ13251211–6456207) that is located at a distance of 94.6 ± 0.3 pc using SPHERE/IRDIS on the VLT. Spectroscopic observations with VLT/X-SHOOTER constrain the mass of the star to $1.00\pm 0.02\, \mathrm{M}_{\odot }$ and an age of $16.7\pm 1.4\,$ Myr. The companion TYC 8998-760-1 b is detected at a projected separation of 1.71″, which implies a projected physical separation of 162 au. Photometric measurements ranging from Y to M band provide a mass estimate of $14\pm 3\, M_\mathrm{jup}$ by comparison to BT-Settl and AMES-dusty isochrones, corresponding to a mass ratio of q = 0.013 ± 0.003 with respect to the primary. We rule out additional companions to TYC 8998-760-1 that are more massive than $12\, M_\mathrm{jup}$ and farther than 12 au away from the host. Future polarimetric and spectroscopic observations of this system with ground and space based observatories will facilitate testing of formation and evolution scenarios shaping the architecture of the circumstellar environment around this ‘young Sun’.

Highlights

With the advent of extreme adaptive optics (AO) assisted, high-contrast imaging instruments at the current generation of 8-m class telescopes, the search and characterisation of directly imaged extra-solar planets has gained momen-Most of these directly imaged companions, are detected around stars that are more massive than the Sun
We report the detection of a co-moving companion around the K3IV star TYC 8998-760-1 (2MASSJ132512116456207) that is located at a distance of 94.6 ± 0.3 pc using SPHERE/infrared dual-band imager and spectrograph (IRDIS) on the VLT
As the masses that are derived from effective temperature, luminosity, individual photometry, and spectral type are all in very good agreement, it is unlikely that the object is not a low-mass companion to TYC 8998-760-1

Summary

Introduction

With the advent of extreme adaptive optics (AO) assisted, high-contrast imaging instruments at the current generation of 8-m class telescopes, the search and characterisation of directly imaged extra-solar planets has gained momen- Most of these directly imaged companions, are detected around stars that are more massive than the Sun. To obtain a statistically significant estimate on the occurrence rates of giant sub-stellar companions on wide orbits around solar-type stars, we started the Young Suns Exoplanet Survey (YSES; Bohn et al in prep.). In addition to the small range of stellar masses, the YSES targets are homogeneous in terms of stellar ages and distances This enables self-consistent reference star differential imaging (RDI; Smith & Terrile 1984; Lafreniere et al 2007) to increase the contrast performance at close separations (Bohn et al in prep.) and minimises uncertainties on the properties of identified companions due to poorly constrained system ages

Results

Discussion

Conclusion