Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1709.01527

Three Small Super-Earths Transiting the nearby star GJ 9827

Prajwal Niraula·Seth Redfield·Fei Dai·Oscar Barragan·Davide Gandolfi·P. Wilson Cauley·Teruyuki Hirano·Judith Korth·Alexis M. S. Smith·Jorge Prieto-Arranz·Sascha Grziwa·Malcolm Fridlund·Carina M. Persson·Anders Bo Justesen·Joshua N. Winn·Simon Albrecht·William D. Cochran·Szilard Csizmadia·Girish M. Duvvuri·Michael Endl·Artie P. Hatzes·John H. Livingston·Norio Narita·David Nespral·Grzegorz Nowak·Martin Patzold·Enric Palle·Vincent Van Eylen
View original source ↗Read source document ↗Export metadata ↓

Abstract

We report on the discovery of three transiting planets around GJ~9827. The planets have radii of 1.75$_{-0.12}^{+0.11 }$, 1.36$_{- 0.09 }^{+ 0.09}$, and 2.10$_{- 0.15 }^{+ 0.15 }$~R$_{\oplus}$, and periods of 1.20896, 3.6480, and 6.2014 days, respectively. The detection was made in Campaign 12 observations as part of our K2 survey of nearby stars. GJ~9827 is a $V = 10.39$~mag K6V star at distance of 30.3 parsecs and the nearest star to be found hosting planets by Kepler and K2. The radial velocity follow-up, high resolution imaging, and detection of multiple transiting objects near commensurability drastically reduce the false positive probability. The orbital periods of GJ~9827~b, c and d planets are very close to the 1:3:5 mean motion resonance. Our preliminary analysis shows that GJ~9827 planets are excellent candidates for atmospheric observations. Besides, the planetary radii span both sides of the rocky and gaseous divide, hence the system will be an asset in expanding our understanding of the threshold.

Explore related subjects

astro-ph.EP

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Prajwal Niraula, Seth Redfield, Fei Dai, Oscar Barragan, Davide Gandolfi, P. Wilson Cauley, Teruyuki Hirano, Judith Korth, Alexis M. S. Smith, Jorge Prieto-Arranz, Sascha Grziwa, Malcolm Fridlund, Carina M. Persson, Anders Bo Justesen, Joshua N. Winn, Simon Albrecht, William D. Cochran, Szilard Csizmadia, Girish M. Duvvuri, Michael Endl, Artie P. Hatzes, John H. Livingston, Norio Narita, David Nespral, Grzegorz Nowak, Martin Patzold, Enric Palle, Vincent Van Eylen. 2017-11-01. Three Small Super-Earths Transiting the nearby star GJ 9827. https://doi.org/10.3847/1538-3881%2Faa957c

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Radiating Bondi Flows I: Dimensionless Framework and Constant Opacity Solutions

In this paper, we extend the foundational work of Bondi (1952) to include the effects of radiative feedback in gas-pressure-dominated environments. We construct steady-state spherically symmetric accretion solutions including radiative heating and cooling. Under the simplifying assumption of a constant opacity, the solutions are controlled by four dimensionless parameters: the adiabatic index $γ$, optical depth through the Bondi radius $τ_B$, dimensionless luminosity at infinity $\tilde{L}_\infty$, and a characteristic dimensionless cooling time $β$. We present numerical solutions across the dimensionless parameter space $(τ_B, \tilde{L}_\infty, β)\in [10^{-3}, 10^3]$. Contrary to radiation-pressure-dominated environments, radiative feedback primarily operates to suppress accretion -- particularly at high $τ_B$, $\tilde{L}_\infty$, and/or $β$. We also present analytic descriptions confirming the suppressive nature of this feedback and give the scalings for the accretion rate $\dot{M}\sim \tilde{L}_\infty^{-5/4}$ at large $\tilde{L}_\infty$, $\dot{M}\sim τ_B^{-10/11}β^{-5/11}$ at large $τ_B$, and $\dot{M}\sim (\tilde{L}_\inftyτ_B)^{-5/8}$ for large $\tilde{L}_\inftyτ_B$. We discuss the potential role of convection in these steady-state solutions, and the particular relevance to problems of planet formation where radiative heating is significant, but the system remains in the gas-pressure-dominated regime.

astro-ph.EP↗
arXiv2026

Radiating Bondi Flows II: Giant Planet Accretion Models

In the core accretion model of giant planet formation, the late stages of runaway growth are regulated by the hydrodynamic infall of gas from the protoplanetary disk. For a subset of planet-disk pairings, this scenario is analogous to the classical Bondi problem, which has motivated a Bondi-like parameterization of accretion in some population synthesis models. Existing models and the associated classical Bondi rate however, are predicated upon an adiabatic equation of state. In reality, the planet and its associated accretion shock supply a luminosity that substantially heats the accretion flow. In Paper I of this series, we demonstrate that such radiative feedback can dramatically suppress accretion by orders of magnitude. Here we quantify this effect under realistic planet-forming conditions. We find that for planets forming in an unperturbed disk, accretion is suppressed by 1-2 orders of magnitude interior to $\sim 10$ AU. For planets that open a gap, this feedback is less dramatic and the effect is $\sim$ 1 order in magnitude. We investigate the effect of various assumptions regarding dust opacities, shock efficiency, and planet radius and find this radiative suppression mechanism to be fairly insensitive to these effects. We also perform full time-dependent simulations demonstrating that the associated adverse entropy profiles are accurate and stable to convection. A simple and flexible set of open-source tools are provided to incorporate this radiative feedback into existing accretion models and population synthesis frameworks.

astro-ph.EP↗
arXiv2026

Assessing the Impact of High-Resolution Imaging on Statistical Validation of TESS Planet Candidates

High-resolution imaging is widely used to constrain false-positive scenarios in exoplanet validation, but it is a finite follow-up resource that reaches only a subset of candidates, and its population-level impact on validation outcomes has not been quantified through controlled removal experiments. Using an automated pipeline built on TRICERATOPS, we compute the false-positive probability (FPP) of 443 TESS planet candidates. For the 264 planet candidates with high-resolution imaging observations, we compute FPP with and without the corresponding contrast curves, allowing us to quantify the impact of the additional data. We find that 72% of 68 contrast-curve bearing validated planets would fail validation without their adopted contrast curves. The fraction requiring imaging decreases with increasing planet size, from 100% below $1.7~R_\oplus$ to $33\%$ above $4~R_\oplus$: within our sample and TRICERATOPS-based analysis, the availability of high-resolution imaging directly limits the yield of small-planet validation and the supply of validated targets for atmospheric characterization. Our analysis statistically validates 64 new TESS planets with sizes spanning 0.94 to 7.83 $R_\oplus$ across hosts of spectral type M through F. Four of these are highly amenable to JWST observations based on the transmission and emission spectroscopy metrics, and each achieves validation only with its imaging constraint.

astro-ph.EP↗