Measuring the Galactic Distribution of Transiting Planets with <i>WFIRST</i>

Montet, Benjamin T.; Yee, Jennifer C.; Penny, Matthew T.

doi:10.1088/1538-3873/aa57fb

Cited by 56 publications

(45 citation statements)

References 116 publications

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“…Most planets discovered via transits and RV are rela-tively close to the Sun (within ∼ 1500 parsecs), but the galactic distribution of planets could be substantially different, which will be measured with the future WFIRST survey (Montet et al 2017). These factors, among others, could all affect planet occurrence, and the true distribution of planets has many dimensions.…”

Section: High Dimensional Distributionmentioning

confidence: 99%

A Joint Mass–Radius–Period Distribution of Exoplanets

Neil

Rogers

2020

ApJ

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The radius-period distribution of exoplanets has been characterized by the Kepler survey, and the empirical mass-radius relation by the subset of Kepler planets with mass measurements. We combine the two in order to constrain the joint mass-radius-period distribution of Kepler transiting planets. We employ hierarchical Bayesian modeling and mixture models to formulate four models with varying complexity and fit these models to the data. We find that the most complex models that treat planets with significant gaseous envelopes, evaporated core planets, and intrinsically rocky planets as three separate populations are preferred by the data and provide the best fit to the observed distribution of Kepler planets. We use these models to calculate occurrence rates of planets in different regimes and to predict masses of Kepler planets, revealing the model dependent nature of both. When using models with envelope mass loss to calculate η ⊕ , we find nearly an order of magnitude drop, indicating that many Earth-like planets discovered with Kepler may be evaporated cores which do not extrapolate out to higher orbital periods. This work provides a framework for higher-dimensional studies of planet occurrence and for using mixture models to incorporate different theoretical populations of planets.

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Section: High Dimensional Distributionmentioning

confidence: 99%

A Joint Mass–Radius–Period Distribution of Exoplanets

Neil

Rogers

2020

ApJ

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“…Additionally, high-cadence two-filter Euclid observations would allow the discrimination of potential exoplanet false-positives caused by microlensed binary sources (e.g. Gaudi 1998) and for tens of thousands of transiting planets that can be discovered in both Euclid and WFIRST microlensing observations (McDonald et al 2014;Montet et al 2017); in both scenarios false positives have chromatic lightcurves, while planets have achromatic lightcurves. Simultaneous Euclid observations could also be used to measure the colors of faint Kuiper belt objects and confirm asteroseismic measurements of bulge giants .…”

Section: Discussionmentioning

confidence: 99%

WFIRST and EUCLID: Enabling the Microlensing Parallax Measurement from Space

Bachelet

Penny

2019

ApJL

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The Wide Field Infrared Survey Telescope (WFIRST) is expected to detect hundreds of free-floating planets, but it will not be able to measure their masses. However, simultaneous microlensing observations by both Euclid and WFIRST spacecraft, separated by ∼100, 000 km in orbits around the Sun-Earth L2 Lagrange point, will enable measurements of microlensing parallax for low-mass lenses such as free-floating planets. Using simple Fisher matrix estimates of the parallax measurement uncertainties, we show that high-cadence observations by Euclid could be used to measure ∼1 free-floating planet microlens parallax per 6 days of simultaneous Euclid observations. Accounting for Euclid's pointing constraints, it could therefore potentially measure ∼20 free-floating planet parallaxes with 120 days of observations split equally between Euclid's main mission and an extended mission, with a potential to increase this number if spacecraft pointing constraints can be relaxed after the end of the main mission. These Euclid observations would also provide additional mass measurements or cross-checks for larger numbers of WFIRST's bound planets, among other benefits to several science cases.

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“…On the other hand, the comparison of microlensing events with models of the Galactic distribution seems to indicate a low (less than 50%) relative abundance of planets in the bulge compared to that in the disk [21], although a fraction closer to unity cannot be ruled out. Future observations from Euclid [22] and WFIRST [23], as well as analysis of present campaigns such as Spitzer [24], will refine the constraint on the abundance ratio of planets in the bulge relative to the disk. For the present study, we will assume that such a ratio is not significantly lower than unity.…”

Section: Planets In the Galactic Bulgementioning

confidence: 96%

The Habitability of the Galactic Bulge

Balbi

Hami

Kovačević

2020

Life

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We present a new investigation of the habitability of the Milky Way bulge, that expands previous studies on the Galactic Habitable Zone. We discuss existing knowledge on the abundance of planets in the bulge, metallicity and the possible frequency of rocky planets, orbital stability and encounters, and the possibility of planets around the central supermassive black hole. We focus on two aspects that can present substantial differences with respect to the environment in the disk: (i) the ionizing radiation environment, due to the presence of the central black hole and to the highest rate of supernovae explosions and (ii) the efficiency of putative lithopanspermia mechanism for the diffusion of life between stellar systems. We use analytical models of the star density in the bulge to provide estimates of the rate of catastrophic events and of the diffusion timescales for life over interstellar distances.

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Measuring the Galactic Distribution of Transiting Planets with WFIRST

Cited by 56 publications

References 116 publications

A Joint Mass–Radius–Period Distribution of Exoplanets

A Joint Mass–Radius–Period Distribution of Exoplanets

WFIRST and EUCLID: Enabling the Microlensing Parallax Measurement from Space

The Habitability of the Galactic Bulge

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