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We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2λ/D (240 mas) in L ′ in MagAO/Clio imaging using the binary differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric acceleration in Gaia DR3, Hipparcos–Gaia proper motion anomaly, and overluminosity compared to single main-sequence stars. We confirmed the companion, HIP 67506 C, at 0.1 arcsec with MagAO-X in 2022 April. We characterized HIP 67506 C MagAO-X photometry and astrometry, and estimated spectral-type K7-M2; we also re-evaluated HIP 67506 A in light of the close companion. Additionally, we show that a previously identified 9 arcsec companion, HIP 67506 B, is a much further distant unassociated background star. We also discuss the utility of indirect signposts in identifying small inner working angle candidate companions. [ABSTRACT FROM AUTHOR]

VHS J1256−1257 AB is an ultracool dwarf binary that hosts a wide-separation planetary-mass companion that is a key target of the JWST Exoplanet Early Release Science programme. Using Keck adaptive optics imaging and aperture masking interferometry, we have determined the host binary's orbit (a = 1.96 ± 0.03 au, P = 7.31 ± 0.02 yr, e = 0.883 ± 0.003) and measured its dynamical total mass (0.141 ± 0.008 M⊙). This total mass is consistent with VHS J1256−1257 AB being a brown dwarf binary or pair of very low-mass stars. In addition, we measured the orbital motion of VHS J1256−1257 b with respect to the barycentre of VHS J1256−1257 AB, finding that the wide companion's orbit is also eccentric (⁠|$e=0.68^{+0.11}_{-0.10}$|⁠), with a mutual inclination of 115○ ± 14○ with respect to the central binary. This orbital architecture is consistent with VHS J1256−1257 b attaining a significant mutual inclination through dynamical scattering and thereafter driving Kozai–Lidov cycles to pump the eccentricity of VHS J1256−1257 AB. We derive a cooling age of 140 ± 20 Myr for VHS J1256−1257 AB from low-mass stellar/substellar evolutionary models. At this age, the luminosity of VHS J1256−1257 b is consistent with both deuterium-inert and deuterium-fusing evolutionary tracks. We thus find a bimodal probability distribution for the mass of VHS J1256−1257 b, either 12.0 ± 0.1  M Jup or 16 ± 1  M Jup, from these models. Future spectroscopic data to measure isotopologues such as HDO and CH3D could break this degeneracy and provide a strong test of substellar models at the deuterium-fusion mass boundary. [ABSTRACT FROM AUTHOR]

The long-period giant planet HR 5183 b has one of the most extreme orbits among exoplanets known to date, and represents a test for models of their dynamical evolution. In this work, we use Hipparcos – Gaia astrometry to measure the orbital inclination of this planet for the first time and find |$i=89.9^{+13.3\circ }_{-13.5}$|⁠ , fully consistent with edge-on. The long orbital period and high eccentricity of HR 5183 b are supported by our results, with |$P=102^{+84}_{-34}$| yr and e = 0.87 ± 0.04. We confirm that HR 5183 forms a physically bound binary with HIP 67291 at a projected separation of 15 400 AU, and derive new constraints on the orbit of this pair. We combine these results to measure the mutual inclination between the planetary and binary orbits; we observe significant evidence for misalignment, which remains even after accounting for bias of the prior towards high mutual inclinations. However, our results are too imprecise to evaluate a recent prediction that the mutual inclination should reflect the formation history of HR 5183 b. Further observations, especially the release of the full Gaia astrometric data, will allow for improved constraints on the planet-binary mutual inclination. |$52 \pm 16\ \hbox{per cent}$| of known planets with eccentricities e ≥ 0.8 are found in multiple star systems, a rate that we find to be greater than for the overall planet population to moderate significance (p = 0.0075). This supports the hypothesis that dynamical interactions with wide stellar companions plays an important role in the formation of highly eccentric exoplanets. [ABSTRACT FROM AUTHOR]

Improving direct detection capability close to the star through improved star subtraction and post-processing techniques is vital for discovering new low-mass companions and characterizing known ones at longer wavelengths. We present results of 17 binary star systems observed with the Magellan adaptive optics system (MagAO) and the Clio infrared camera on the Magellan Clay Telescope using binary differential imaging (BDI). BDI is an application of reference differential imaging (RDI) and angular differential imaging (ADI) applied to wide binary star systems (2 arcsec <Δρ < 10 arcsec) within the isoplanatic patch in the infrared. Each star serves as the point spread function (PSF) reference for the other, and we performed PSF estimation and subtraction using principal component analysis. We report contrast and mass limits for the 35 stars in our initial survey using BDI with MagAO/Clio in L ′ and 3.95 µm bands. Our achieved contrasts varied between systems, and spanned a range of contrasts from 3.0 to 7.5 magnitudes and a range of separations from 0.2 to 2 arcsec. Stars in our survey span a range of masses, and our achieved contrasts correspond to late-type M-dwarf masses down to ∼10  M Jup. We also report detection of a candidate companion signal at 0.2 arcsec (18 au) around HIP 67506 A (SpT G5V, mass ∼1.2 M⊙), which we estimate to be |$\sim 60-90 \, \rm{M_{Jup}}$|⁠. We found that the effectiveness of BDI is highest for approximately equal brightness binaries in high-Strehl conditions. [ABSTRACT FROM AUTHOR]

There is an urgent need to persuade the public to follow behavioral guidelines in order to end the COVID-19 pandemic. Using cognitive dissonance as a guide, the current study's aim was to increase compliance with coronavirus safety measures, such as social distancing, wearing masks, and getting vaccinated. In Phase 1, participants experienced dissonance by advocating consistent adherence to safety protocols and recalling instances when they did not follow them. Their attitudes and behavioral intentions were measured. A week later, we assessed reported behavior. We found that dissonance participants complied more with guidelines and were more likely to seek vaccination than participants in three non-dissonance control conditions. We conclude by recommending ways of implementing the findings in the current COVID-19 crisis. [ABSTRACT FROM AUTHOR]

The orbits of binary stars and planets, particularly eccentricities and inclinations, encode the angular momentum within these systems. Within stellar multiple systems, the magnitude and (mis)alignment of angular momentum vectors among stars, disks, and planets probes the complex dynamical processes guiding their formation and evolution. The accuracy of the Gaia catalog can be exploited to enable comparison of binary orbits with known planet or disk inclinations without costly long-term astrometric campaigns. We show that Gaia astrometry can place meaningful limits on orbital elements in cases with reliable astrometry, and discuss metrics for assessing the reliability of Gaia DR2 solutions for orbit fitting. We demonstrate our method by determining orbital elements for three systems (DS Tuc AB, GK/GI Tau, and Kepler-25/KOI-1803) using Gaia astrometry alone. We show that DS Tuc AB's orbit is nearly aligned with the orbit of DS Tuc Ab, GK/GI Tau's orbit might be misaligned with their respective protoplanetary disks, and the Kepler-25/KOI-1803 orbit is not aligned with either component's transiting planetary system. We also demonstrate cases where Gaia astrometry alone fails to provide useful constraints on orbital elements. To enable broader application of this technique, we introduce the python tool lofti _ gaiaDR2 to allow users to easily determine orbital element posteriors. [ABSTRACT FROM AUTHOR]