Ertel, S.S.ErtelDefrère, D.D.DefrèreHinz, P.P.HinzMennesson, B.B.MennessonKennedy, G. M.G. M.KennedyDanchi, W. C.W. C.DanchiGelino, C.C.GelinoHill, J. M.J. M.HillHoffmann, W. F.W. F.HoffmannRieke, G.G.RiekeShannon, A.A.ShannonSpalding, E.E.SpaldingStone, J. M.J. M.StoneVaz, A.A.VazWeinberger, A. J.A. J.WeinbergerWillems, P.P.WillemsAbsil, O.O.AbsilArbo, P.P.ArboBailey, V. P.V. P.BaileyBeichman, C.C.BeichmanBryden, G.G.BrydenDowney, E. C.E. C.DowneyDurney, O.O.DurneyESPOSITO, SimoneSimoneESPOSITOGaspar, A.A.GasparGrenz, P.P.GrenzHaniff, C. A.C. A.HaniffLeisenring, J. M.J. M.LeisenringMarion, L.L.MarionMcMahon, T. J.T. J.McMahonMillan-Gabet, R.R.Millan-GabetMontoya, M.M.MontoyaMorzinski, K. M.K. M.MorzinskiPINNA, EnricoEnricoPINNAPower, J.J.PowerPUGLISI, Alfio TimothyAlfio TimothyPUGLISIRoberge, A.A.RobergeSerabyn, E.E.SerabynSkemer, A. J.A. J.SkemerStapelfeldt, K.K.StapelfeldtSu, K. Y. L.K. Y. L.SuVaitheeswaran, V.V.VaitheeswaranWyatt, M. C.M. C.Wyatt2021-02-032021-02-0320180004-6256http://hdl.handle.net/20.500.12386/30203The Hunt for Observable Signatures of Terrestrial Systems survey searches for dust near the habitable zones (HZs) around nearby, bright main-sequence stars. We use nulling interferometry in the N band to suppress the bright stellar light and to probe for low levels of HZ dust around the 30 stars observed so far. Our overall detection rate is 18%, including four new detections, among which are the first three around Sun-like stars and the first two around stars without any previously known circumstellar dust. The inferred occurrence rates are comparable for early-type and Sun-like stars, but decrease from {60}<SUB>-21</SUB><SUP>+16</SUP>% for stars with previously detected cold dust to {8}<SUB>-3</SUB><SUP>+10</SUP>% for stars without such excess, confirming earlier results at higher sensitivity. For completed observations on individual stars, our sensitivity is five to ten times better than previous results. Assuming a lognormal excess luminosity function, we put upper limits on the median HZ dust level of 13 zodis (95% confidence) for a sample of stars without cold dust and of 26 zodis when focusing on Sun-like stars without cold dust. However, our data suggest that a more complex luminosity function may be more appropriate. For stars without detectable Large Binocular Telescope Interferometer (LBTI) excess, our upper limits are almost reduced by a factor of two, demonstrating the strength of LBTI target vetting for future exo-Earth imaging missions. Our statistics are limited so far, and extending the survey is critical to informing the design of future exo-Earth imaging surveys.STAMPAenArticle10.3847/1538-3881/aab7172-s2.0-85047305423000439356900002https://iopscience.iop.org/article/10.3847/1538-3881/aab7172018AJ....155..194EFIS/05 - ASTRONOMIA E ASTROFISICA