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Divergent Pathways: How Pre-Orientation Programs Can Shape the Transition to College for First-Generation, Low-Income Students
First-generation, low-income (FGLI) students attend college at historically high rates in the United States. However, FGLI students continue to struggle in transitioning to college, particularly in elite universities. In this article, we engage with interview and supplemental survey data from 40 FGLI students at an elite university to demonstrate how self-advocacy skillsâconceptualized as a form of cultural capitalâcan support FGLI students' transition into college. We do this through the case of pre-orientation programs, which are increasingly offered across universities, where half of the sample participated in pre-orientation and half did not. We interviewed both subsets at the start of their first academic year, as well as during their COVID-19-induced departure from campus residences. In response, we argue that students who participated in pre-orientation more often demonstrate self-advocacy skills, both in-person and online, especially in comparison with those who did not participate. We show that forming relationships with peers, as well as faculty and staff, during pre-orientation is key to enacting self-advocacy. Lastly, we also respond to previous studies that typically associate self-advocacy skills with the cultural competencies of higher-income and continuing-generation students, while making clear how these skills can benefit FGLI students in transitioning into school
TOI-561 b: A Low Density Ultra-Short Period "Rocky" Planet around a Metal-Poor Star
TOI-561 is a galactic thick disk star hosting an ultra-short period (0.45 day
orbit) planet with a radius of 1.37 R, making it one of the most
metal-poor ([Fe/H] = -0.41) and oldest (10 Gyr) sites where an
Earth-sized planet has been found. We present new simultaneous radial velocity
measurements (RVs) from Gemini-N/MAROON-X and Keck/HIRES, which we combined
with literature RVs to derive a mass of M=2.24 0.20 M.
We also used two new Sectors of TESS photometry to improve the radius
determination, finding R=, and confirming that
TOI-561 b is one of the lowest-density super-Earths measured to date (=
4.8 0.5 g/cm). This density is consistent with an iron-poor rocky
composition reflective of the host star's iron and rock-building element
abundances; however, it is also consistent with a low-density planet with a
volatile envelope. The equilibrium temperature of the planet (2300 K)
suggests that this envelope would likely be composed of high mean molecular
weight species, such as water vapor, carbon dioxide, or silicate vapor, and is
likely not primordial. We also demonstrate that the composition determination
is sensitive to the choice of stellar parameters, and that further measurements
are needed to determine if TOI-561 b is a bare rocky planet, a rocky planet
with an optically thin atmosphere, or a rare example of a non-primordial
envelope on a planet with a radius smaller than 1.5 R.Comment: Accepted to AJ on 11/28/202
Investigating the Atmospheric Mass Loss of the Kepler-105 Planets Straddling the Radius Gap
An intriguing pattern among exoplanets is the lack of detected planets
between approximately R and R. One proposed
explanation for this "radius gap" is the photoevaporation of planetary
atmospheres, a theory that can be tested by studying individual planetary
systems. Kepler-105 is an ideal system for such testing due to the ordering and
sizes of its planets. Kepler-105 is a sun-like star that hosts two planets
straddling the radius gap in a rare architecture with the larger planet closer
to the host star ( R, days, R, days). If photoevaporation sculpted the
atmospheres of these planets, then Kepler-105b would need to be much more
massive than Kepler-105c to retain its atmosphere, given its closer proximity
to the host star. To test this hypothesis, we simultaneously analyzed radial
velocities (RVs) and transit timing variations (TTVs) of the Kepler-105 system,
measuring disparate masses of M ( g cm) and M ( g cm). Based on these masses, the difference in gas
envelope content of the Kepler-105 planets could be entirely due to
photoevaporation (in 76\% of scenarios), although other mechanisms like
core-powered mass loss could have played a role for some planet albedos.Comment: 14 pages, 3 figures, 2 table
The TESS-Keck Survey: Science Goals and Target Selection
Space-based transit missions such as Kepler and TESS have demonstrated that
planets are ubiquitous. However, the success of these missions heavily depends
on ground-based radial velocity (RV) surveys, which combined with transit
photometry can yield bulk densities and orbital properties. While most Kepler
host stars are too faint for detailed follow-up observations, TESS is detecting
planets orbiting nearby bright stars that are more amenable to RV
characterization. Here we introduce the TESS-Keck Survey (TKS), an RV program
using ~100 nights on Keck/HIRES to study exoplanets identified by TESS. The
primary survey aims are investigating the link between stellar properties and
the compositions of small planets; studying how the diversity of system
architectures depends on dynamical configurations or planet multiplicity;
identifying prime candidates for atmospheric studies with JWST; and
understanding the role of stellar evolution in shaping planetary systems. We
present a fully-automated target selection algorithm, which yielded 103 planets
in 86 systems for the final TKS sample. Most TKS hosts are inactive,
solar-like, main-sequence stars (4500 K < Teff < 6000 K) at a wide range of
metallicities. The selected TKS sample contains 71 small planets (Rp < 4 Re),
11 systems with multiple transiting candidates, 6 sub-day period planets and 3
planets that are in or near the habitable zone of their host star. The target
selection described here will facilitate the comparison of measured planet
masses, densities, and eccentricities to predictions from planet population
models. Our target selection software is publicly available (at
https://github.com/ashleychontos/sort-a-survey) and can be adapted for any
survey which requires a balance of multiple science interests within a given
telescope allocation.Comment: 23 pages, 10 figures, 5 table
Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets
Mass, radius, and age measurements of young (<100 Myr) planets have the power
to shape our understanding of planet formation. However, young stars tend to be
extremely variable in both photometry and radial velocity, which makes
constraining these properties challenging. The V1298 Tau system of four ~0.5
Rjup planets transiting a pre-main sequence star presents an important, if
stress-inducing, opportunity to directly observe and measure the properties of
infant planets. Su\'arez-Mascare\~no et al. (2021) published
radial-velocity-derived masses for two of the V1298 Tau planets using a
state-of-the-art Gaussian Process regression framework. The planetary densities
computed from these masses were surprisingly high, implying extremely rapid
contraction after formation in tension with most existing planet formation
theories. In an effort to further constrain the masses of the V1298 Tau
planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with
published RVs and photometry. Through performing a suite of cross validation
tests, we found evidence that the preferred model of SM21 suffers from
overfitting, defined as the inability to predict unseen data, rendering the
masses unreliable. We detail several potential causes of this overfitting, many
of which may be important for other RV analyses of other active stars, and
recommend that additional time and resources be allocated to understanding and
mitigating activity in active young stars such as V1298 Tau.Comment: 26 pages, 12 figures; published in A
The TESS-Keck Survey. XV. Precise Properties of 108 TESS Planets and Their Host Stars
We present the stellar and planetary properties for 85 TESS Objects of
Interest (TOIs) hosting 108 planet candidates which comprise the TESS-Keck
Survey (TKS) sample. We combine photometry, high-resolution spectroscopy, and
Gaia parallaxes to measure precise and accurate stellar properties. We then use
these parameters as inputs to a lightcurve processing pipeline to recover
planetary signals and homogeneously fit their transit properties. Among these
transit fits, we detect significant transit-timing variations among at least
three multi-planet systems (TOI-1136, TOI-1246, TOI-1339) and at least one
single-planet system (TOI-1279). We also reduce the uncertainties on
planet-to-star radius ratios across our sample, from a median
fractional uncertainty of 8.8 among the original TOI Catalog values to
3.0 among our updated results. With this improvement, we are able to
recover the Radius Gap among small TKS planets and find that the topology of
the Radius Gap among our sample is broadly consistent with that measured among
Kepler planets. The stellar and planetary properties presented here will
facilitate follow-up investigations of both individual TOIs and broader trends
in planet properties, system dynamics, and the evolution of planetary systems.Comment: Accepted at The Astronomical Journal; 21 pages, 9 figure
The TESS-Keck Survey. XII. A Dense 1.8 R â Ultra-short-period Planet Possibly Clinging to a High-mean-molecular-weight Atmosphere after the First Gigayear
The extreme environments of ultra-short-period planets (USPs) make excellent laboratories to study how exoplanets obtain, lose, retain, and/or regain gaseous atmospheres. We present the confirmation and characterization of the USP TOI-1347 b, a 1.8±0.1 Râ planet on a 0.85 day orbit that was detected with photometry from the TESS mission. We measured radial velocities of the TOI-1347 system using Keck/HIRES and HARPS-N and found the USP to be unusually massive at 11.1±1.2 Mâ. The measured mass and radius of TOI-1347 b imply an Earth-like bulk composition. A thin H/He envelope (>0.01% by mass) can be ruled out at high confidence. The system is between 1 and 1.8 Gyr old; therefore, intensive photoevaporation should have concluded. We detected a tentative phase curve variation (3Ï) and a secondary eclipse (2Ï) in TESS photometry, which if confirmed could indicate the presence of a high-mean-molecular-weight atmosphere. We recommend additional optical and infrared observations to confirm the presence of an atmosphere and investigate its composition
The TESS-Keck Survey. III. A Stellar Obliquity Measurement of TOI-1726 c
We report the measurement of a spectroscopic transit of TOI-1726c, one of two planets transiting a G-type star with V = 6.9 in the Ursa Major Moving Group (~400 Myr). With a precise age constraint from cluster membership, TOI-1726 provides a great opportunity to test various obliquity excitation scenarios that operate on different timescales. By modeling the RossiterâMcLaughlin (RM) effect, we derived a sky-projected obliquity of â1^(+35)_(â32)â. This result rules out a polar/retrograde orbit and is consistent with an aligned orbit for planet c. Considering the previously reported, similarly prograde RM measurement of planet b and the transiting nature of both planets, TOI-1726 tentatively conforms to the overall picture that compact multitransiting planetary systems tend to have coplanar, likely aligned orbits. TOI-1726 is also a great atmospheric target for understanding differential atmospheric loss of sub-Neptune planets (planet b 2.2 Râ and c 2.7 Râ both likely underwent photoevaporation). The coplanar geometry points to a dynamically cold history of the system that simplifies any future modeling of atmospheric escape
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