229 research outputs found

    The Effect of Taboo Words and Reprimands in an Audio-Visual Modified Stroop Task

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    Previous research has found that participants respond less efficiently to taboo words in a modified emotional Stroop task than to neutral words because of the emotional nature of taboo words. Additionally, there is some evidence that the extent to which these words impact performance depends on whether the words appear in a participant’s native language. More specifically, the taboo effect has been found to be more pronounced in a person’s native language. One purpose of the current study was to determine whether previous results in a taboo Stroop task would be replicated. Another purpose of this study was to determine if the taboo effect would extend to reprimands. Reprimands, like taboo words, are considered to be highly emotional. Taboo words were previously found to be more arousing in native speakers when presented auditorily compared to when presented visually. In the current study, the stimuli were simultaneously presented visually on a computer screen and auditorily over headphones. During a taboo Stroop task, participants were randomly presented with taboo and neutral words in colored fonts. During a reprimand Stroop task, participants were randomly presented with reprimanding phrases and neutral phrases, and only the last word in these phrases was in a colored font. Participants were instructed to indicate the font color. I analyzed participants’ reaction times and the maximum deviation of their mouse movements. Participants in both groups responded significantly more slowly to taboo words compared to neutral words. Mouse movements were also more deviated in response to taboo words than neutral words. Interestingly, participants had significantly faster (not slower) responses for reprimands compared to neutral phrases. Group differences were not statistically significant. Given participants’ early age of acquisition, it is possible that the non-native participants behaved more like native speakers. Consequently, participants with later ages of acquisition should be recruited in future research

    No Sub-Saturn Mass Planet Desert in the CORALIE/HARPS Radial Velocity Sample

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    We analyze the CORALIE/HARPS sample of exoplanets (Mayor et al. 2011) found by the Doppler radial velocity method for signs of the predicted "desert" at 10-100M100 M_\odot caused by runaway gas accretion at semimajor axes of <3< 3\,AU. We find that these data are not consistent with this prediction. This result is similar to the finding by the MOA gravitational microlensing survey that found no desert in the exoplanet distribution for exoplanets in slightly longer period orbits and somewhat lower host masses (Suzuki et al. 2018). Together, these results imply that the runaway accretion scenario of the core accretion theory does not have a large influence on the final mass and semimajor axis distribution of exoplanets.Comment: accepted by the Astronomical Journal, 19 pages with 5 figure

    Hints for a Turnover at the Snow Line in the Giant Planet Occurrence Rate

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    The orbital distribution of giant planets is crucial for understanding how terrestrial planets form and predicting yields of exoplanet surveys. Here, we derive giant planets occurrence rates as a function of orbital period by taking into account the detection efficiency of the Kepler and radial velocity (RV) surveys. The giant planet occurrence rates for Kepler and RV show the same rising trend with increasing distance from the star. We identify a break in the RV giant planet distribution between ~2-3 au -- close to the location of the snow line in the Solar System -- after which the occurrence rate decreases with distance from the star. Extrapolating a broken power-law distribution to larger semi-major axes, we find good agreement with the ~ 1% planet occurrence rates from direct imaging surveys. Assuming a symmetric power law, we also estimate that the occurrence of giant planets between 0.1-100 au is 26.6 +7.5 -5.4% for planets with masses 0.1-20MJ and decreases to 6.2 +1.5 -1.2% for planets more massive than Jupiter. This implies that only a fraction of the structures detected in disks around young stars can be attributed to giant planets. Various planet population synthesis models show good agreement with the observed distribution, and we show how a quantitative comparison between model and data can be used to constrain planet formation and migration mechanisms.Comment: 16 pages, 10 figure

    No Evidence for More Earth-sized Planets in the Habitable Zone of Kepler's M versus FGK Stars

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    Reliable detections of Earth-sized planets in the habitable zone remain elusive in the Kepler sample, even for M dwarfs. The Kepler sample was once thought to contain a considerable number of M dwarf stars (Teff<4000T_\mathrm{eff} < 4000 K), which hosted enough Earth-sized ([0.5,1.5][0.5,1.5] R_\oplus) planets to estimate their occurrence rate (η\eta_\oplus) in the habitable zone. However, updated stellar properties from Gaia have shifted many Kepler stars to earlier spectral type classifications, with most stars (and their planets) now measured to be larger and hotter than previously believed. Today, only one partially-reliable Earth-sized candidate remains in the optimistic habitable zone, and zero in the conservative zone. Here we performed a new investigation of Kepler's Earth-sized planets orbiting M dwarf stars, using occurrence rate models with considerations of updated parameters and candidate reliability. Extrapolating our models to low instellations, we found an occurrence rate of η=8.588.22+17.94%\eta_\oplus={8.58}_{-8.22}^{+17.94}\% for the conservative habitable zone (and 14.2212.71+24.96%{14.22}_{-12.71}^{+24.96}\% for the optimistic), consistent with previous works when considering the large uncertainties. Comparing these estimates to those from similarly comprehensive studies of Sun-like stars, we found that the current Kepler sample does not offer evidence to support an increase in η\eta_\oplus from FGK to M stars. While the Kepler sample is too sparse to resolve an occurrence trend between early and mid-to-late M dwarfs for Earth-sized planets, studies including larger planets and/or data from the K2 and TESS missions are well-suited to this task.Comment: 22 pages, 11 figures, 2 tables; Accepted for publication in A

    The shadow knows: using shadows to investigate the structure of the pretransitional disk of HD 100453

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    We present GPI polarized intensity imagery of HD 100453 in Y-, J-, and K1 bands which reveals an inner gap (9189 - 18 au), an outer disk (183918-39 au) with two prominent spiral arms, and two azimuthally-localized dark features also present in SPHERE total intensity images (Wagner 2015). SED fitting further suggests the radial gap extends to 11 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by a inner disk which is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D (Whitney 2013), we construct a model of the disk which allows us to determine its physical properties in more detail. From the angular separation of the features we measure the difference in inclination between the disks 45^{\circ}, and their major axes, PA = 140^{\circ} east of north for the outer disk and 100^{\circ}for the inner disk. We find an outer disk inclination of 25±1025 \pm 10^{\circ} from face-on in broad agreement with the Wagner 2015 measurement of 34^{\circ}. SPHERE data in J- and H-bands indicate a reddish disk which points to HD 100453 evolving into a young debris disk

    Variability of Disk Emission in Pre-Main Sequence and Related Stars IV. Investigating the Structural Changes in the Inner Disk Region of MWC 480

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    We present five epochs of near IR observations of the protoplanetary disk around MWC 480 (HD31648) obtained with the SpeX spectrograph on NASA's Infrared Telescope Facility (IRTF) between 2007 and 2013, inclusive. Using the measured line fluxes in the Pa beta and Br gamma lines, we found the mass accretion rates to be (1.43 - 2.61)x10^-8 Msun y^-1 and (1.81 - 2.41)x10^-8 Msun y^-1 respectively, but which varied by more than 50% from epoch to epoch. The spectral energy distribution (SED)reveals a variability of about 30% between 1.5 and 10 microns during this same period of time. We investigated the variability using of the continuum emission of the disk in using the Monte-Carlo Radiative Transfer Code (MCRT) HOCHUNK3D. We find that varying the height of the inner rim successfully produces a change in the NIR flux, but lowers the far IR emission to levels below all measured fluxes. Because the star exhibits bipolar flows, we utilized a structure that simulates an inner disk wind to model the variability in the near IR, without producing flux levels in the far IR that are inconsistent with existing data. For this object, variable near IR emission due to such an outflow is more consistent with the data than changing the scale height of the inner rim of the disk.Comment: 19 pages, 14 figure

    Scaling K2 VII: Evidence for a high occurrence rate of hot sub-Neptunes at intermediate ages

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    The NASA K2 mission obtained high precision time-series photometry for four young clusters, including the near-twin 600-800 Myr-old Praesepe and Hyades clusters. Hot sub-Neptunes are highly prone to mass-loss mechanisms, given their proximity to the the host star and the weakly bound gaseous envelopes, and analyzing this population at young ages can provide strong constraints on planetary evolution models. Using our automated transit detection pipeline, we recover 15 planet candidates across the two clusters, including 10 previously confirmed planets. We find a hot sub-Neptune occurrence rate of 79-107% for GKM stars in the Praesepe cluster. This is 2.5-3.5 sigma higher than the occurrence rate of 16.54+1.00-0.98% for the same planets orbiting the ~3-9 Gyr-old GKM field stars observed by K2, even after accounting for the slightly super-solar metallicity ([Fe/H]~0.2 dex) of the Praesepe cluster. We examine the effect of adding ~100 targets from the Hyades cluster, and extending the planet parameter space under examination, and find similarly high occurrence rates in both cases. The high occurrence rate of young, hot sub-Neptunes could indicate either that these planets are undergoing atmospheric evolution as they age, or that planetary systems that formed when the Galaxy was much younger are substantially different than from today. Under the assumption of the atmospheric mass-loss scenario, a significantly higher occurrence rate of these planets at the intermediate ages of Praesepe and Hyades appears more consistent with the core-powered mass loss scenario sculpting the hot sub-Neptune population, compared to the photoevaporation scenario.Comment: 14 pages, 6 figures, published in A

    Using Photometrically-Derived Properties of Young Stars to Refine TESS's Transiting Young Planet Survey Completeness

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    The demographics of young exoplanets can shed light onto their formation and evolution processes. Exoplanet properties are derived from the properties of their host stars. As such, it is important to accurately characterize the host stars since any systematic biases in their derivation can negatively impact the derivation of planetary properties. Here, we present a uniform catalog of photometrically-derived stellar effective temperatures, luminosities, radii, and masses for 4,865 young (<1 Gyr) stars in 31 nearby clusters and moving groups within 200 pc. We compared our photometrically-derived properties to a subset of those derived from spectra, and found them to be in good agreement. We also investigated the effect of stellar properties on the detection efficiency of transiting short-period young planets with TESS as calculated in Fernandes et al. 2022, and found an overall increase in the detection efficiency when the new photometrically derived properties were taken into account. Most notably, there is a 1.5 times increase in the detection efficiencies for sub-Neptunes/Neptunes (1.8-6 Re) implying that, for our sample of young stars, better characterization of host star properties can lead to the recovery of more small transiting planets. Our homogeneously derived catalog of updated stellar properties, along with a larger unbiased stellar sample and more detections of young planets, will be a crucial input to the accurate estimation of the occurrence rates of young short-period planets.Comment: 16 pages, 5 Figures, 3 Tables. Revised and resubmitted to AJ after a favorable referee report. Co-First Author

    Differences in the gas and dust distribution in the transitional disk of a sun-like young star, PDS 70

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    We present ALMA 0.87 mm continuum, HCO+ J=4--3 emission line, and CO J=3--2 emission line data of the disk of material around the young, Sun-like star PDS 70. These data reveal the existence of a possible two component transitional disk system with a radial dust gap of 0."2 +/- 0."05, an azimuthal gap in the HCO+ J=4--3 moment zero map, as well as two bridge-like features in the gas data. Interestingly these features in the gas disk have no analogue in the dust disk making them of particular interest. We modeled the dust disk using the Monte Carlo radiative transfer code HOCHUNK3D (Whitney et al. 2013) using a two disk components. We find that there is a radial gap that extends from 15-60 au in all grain sizes which differs from previous work

    Scaling K2. VI. Reduced Small Planet Occurrence in High Galactic Amplitude Stars

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    In this study, we performed a homogeneous analysis of the planets around FGK dwarf stars observed by the Kepler and K2 missions, providing spectroscopic parameters for 310 K2 targets -- including 239 Scaling K2 hosts -- observed with Keck/HIRES. For orbital periods less than 40 days, we found that the distribution of planets as a function of orbital period, stellar effective temperature, and metallicity was consistent between K2 and Kepler, reflecting consistent planet formation efficiency across numerous ~1 kpc sight-lines in the local Milky Way. Additionally, we detected a 3X excess of sub-Saturns relative to warm Jupiters beyond 10 days, suggesting a closer association between sub-Saturn and sub-Neptune formation than between sub-Saturn and Jovian formation. Performing a joint analysis of Kepler and K2 demographics, we observed diminishing super-Earth, sub-Neptune, and sub-Saturn populations at higher stellar effective temperatures, implying an inverse relationship between formation and disk mass. In contrast, no apparent host-star spectral-type dependence was identified for our population of Jupiters, which indicates gas-giant formation saturates within the FGK mass regimes. We present support for stellar metallicity trends reported by previous Kepler analyses. Using GAIA DR3 proper motion and RV measurements, we discovered a galactic location trend: stars that make large vertical excursions from the plane of the Milky Way host fewer super-Earths and sub-Neptunes. While oscillation amplitude is associated with metallicity, metallicity alone cannot explain the observed trend, demonstrating that galactic influences are imprinted on the planet population. Overall, our results provide new insights into the distribution of planets around FGK dwarf stars and the factors that influence their formation and evolution.Comment: 28 Pages, 12 Figures, 3 Tables; Accepted for Publication A
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