229 research outputs found
The Effect of Taboo Words and Reprimands in an Audio-Visual Modified Stroop Task
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
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- caused by runaway gas accretion at semimajor axes of 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
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
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 ( K), which hosted enough Earth-sized ( R) planets to
estimate their occurrence rate () 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
for the conservative habitable zone
(and 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 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
We present GPI polarized intensity imagery of HD 100453 in Y-, J-, and K1
bands which reveals an inner gap ( au), an outer disk ( 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 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, and their major axes, PA = 140 east
of north for the outer disk and 100for the inner disk. We find an
outer disk inclination of from face-on in broad agreement
with the Wagner 2015 measurement of 34. 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
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
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
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
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
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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