ISPY: NACO Imaging Survey for Planets around Young stars

Abstract

Context. Planet formation is a frequent process, but little observational constraints exist about the mechanisms involved, especially for giant planets at large separation. The NaCo-ISPY large program is a 120 night L -band direct imaging survey aimed at investigating the giant planet population on wide orbits (a > 10 au) around stars hosting disks.Aims. Here we present the statistical analysis of a subsample of 45 young stars surrounded by protoplanetary disks (PPDs). This is the largest imaging survey uniquely focused on PPDs to date. Our goal is to search for young forming companions embedded in the disk material and to constrain their occurrence rate in relation to the formation mechanism. Methods. We used principal component analysis based point spread function subtraction techniques to reveal young companions forming in the disks. We calculated detection limits for our datasets and adopted a black-body model to derive temperature upper limits of potential forming planets. We then used Monte Carlo simulations to constrain the population of forming gas giant companions and compare our results to different types of formation scenarios. Results. Our data revealed a new binary system (HD38120) and a recently identified triple system with a brown dwarf companion orbiting a binary system (HD101412), in addition to 12 known companions. Furthermore, we detected signals from 17 disks, two of which (HD72106 and T CrA) were imaged for the first time. We reached median detection limits of L = 15.4 mag at 2 . 0, which were used to investigate the temperature of potentially embedded forming companions. We can constrain the occurrence of forming planets with semi-major axis a in [20 − 500] au and T eff in [600 − 3000] K to be 21.2 +24.3 −13.6 %, 14.8 +17.5 −9.6 %, and 10.8 +12.6 −7.0 % for R p = 2, 3, 5 R J , which is in line with the statistical results obtained for more evolved systems from other direct imaging surveys. These values are obtained under the assumption that extinction from circumstellar and circumplanetary material does not affect the companion signal, but we show the potential impact these factors might have on the detectability of forming objects. Conclusions. The NaCo-ISPY data confirm that massive bright planets accreting at high rates are rare. More powerful instruments with better sensitivity in the near-to mid-infrared (MIR) are likely required to unveil the wealth of forming planets sculpting the observed disk substructures.

MagAO-X and HST High-contrast Imaging of the AS209 Disk at Hα

“…The data, presented in Cugno et al (2023), exclude the presence of a companion brighter than 17.2 mag, which translates in an absolute magnitude of 11.8 mag at ¢ L . Even though Cugno et al (2023) showed the risk of using evolutionary models to transform IR brightness measurements into mass estimates, we use the detection limits to obtain a rough estimate of what NIR high-contrast imaging can exclude, assuming a clear view of the planet photosphere and no contribution of the accretion luminosity at ¢ L . For hot-start scenarios like AMES-Cond, NaCo limits exclude objects with M p > 1.5 M J , a very tight upper limit.…”

“…This hypothesis is supported by the direct detection of two confirmed protoplanets in the cavity of the transition disk PDS70 (Keppler et al 2018;Haffert et al 2019). However, despite significant observational efforts, no other confirmed planet in the cavities of other disks has been detected, neither in the infrared (IR; Asensio-Torres et al 2021;Cugno et al 2023) nor in the emission lines associated with accretion (Cugno et al 2019;Xie et al 2020;Zurlo et al 2020;Follette et al 2022;Huélamo et al 2022). Two candidates have been directly detected through Hα emission (LkCa15 b and AB Aur b; Sallum et al 2015;Currie et al 2022): the first has never been redetected, and near-infrared (NIR) observations suggest it could be a reprocessed scattered light feature (Currie et al 2019), while the second one shows Hα emission consistent with scattered light from the disk (Zhou et al 2022) and requires further investigation.…”

JWST/NIRCam Imaging of Young Stellar Objects. II. Deep Constraints on Giant Planets and a Planet Candidate Outside of the Spiral Disk Around SAO 206462

“…The gray dashed vertical line represents the size of the spirals detected in scattered light (consistent with Stolker et al 2016), and therefore marks the region where the limits can not be trusted. Indeed, at shorter separations the physical signal from the disk and the strong self-subtraction prevent the noise from being independent and identically distributed, and the statistics should be treated with caution (Cugno et al 2023a). For the SW filters, the narrow filter reaches a lower sensitivity than the broad filter.…”

“…Consequently, many of these disks have been the target of direct imaging campaigns in the NIR, where we can search for thermal emission from forming planets, and at optical wavelengths, which probe accretion tracers like Hα. Most of these efforts did not result in protoplanet detections (e.g., Cugno et al 2019;Zurlo et al 2020;Asensio-Torres et al 2021;Huélamo et al 2022;Cugno et al 2023a;Follette et al 2023) despite recent detection of a growing number of protoplanets and protoplanet candidates (e.g., PDS70b and c, AB Aur b, HD169142b, AS209 b, MWC758 b and c; Reggiani et al 2014;Keppler et al 2018;Müller et al 2018;Bae et al 2022;Currie et al 2022;Hammond et al 2023;Wagner et al 2023).…”

Substructures in Compact Disks of the Taurus Star-forming Region

“…Our values are consistent with these results within 1σ. Perhaps the most relevant result comes from the NaCo-ISPY large program, where young planets were searched around 45 young stars surrounded by protoplanetary disks(Cugno et al 2023). Most of the stars in the survey have M * > M e .…”