Exploring exoplanet populations with NASA’s Kepler Mission

Batalha, Natalie M.

doi:10.1073/pnas.1304196111

Cited by 241 publications

(174 citation statements)

References 93 publications

(65 reference statements)

Supporting

Mentioning

170

Contrasting

Order By: Relevance

“…The closely orbiting exoplanets (periods less than ~100 days) modeled in this study comprise the majority of known, low mass exoplanets (e.g. Batalha 2014). That XUV-driven hydrodynamic atmospheric escape is important for these planets is not surprising given the large XUV fluxes present at such short orbital periods.…”

Section: Discussionmentioning

confidence: 99%

Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Lehmer

Catling

2017

ApJ

View full text Add to dashboard Cite

Recent observations and analysis of low mass (<10 M  ), exoplanets have found that rocky planets only have radii up to 1.5-2 R  . Two general hypotheses exist for the cause of the dichotomy between rocky and gas-enveloped planets (or possible water worlds): either low mass planets do not necessarily form thick atmospheres of a few wt. %, or the thick atmospheres on these planets easily escape driven by x-ray and extreme ultraviolet (XUV) emissions from young parent stars. Here we show that a cutoff between rocky and gas-enveloped planets due to hydrodynamic escape is most likely to occur at a mean radius of 1.760.38 (2) R  around Sunlike stars. We examine the limit in rocky planet radii predicted by hydrodynamic escape across a wide range of possible model inputs using 10,000 parameter combinations drawn randomly from plausible parameter ranges. We find a cutoff between rocky and gas-enveloped planets that agrees with the observed cutoff. The large cross-section available for XUV absorption in the extremely distended primitive atmospheres of low mass planets results in complete loss of atmospheres during the ~100 Myr phase of stellar XUV saturation. In contrast, more massive planets have less distended atmospheres and less escape, and so retain thick atmospheres through XUV saturation and then indefinitely as the XUV and escape fluxes drop over time. The agreement between our model and exoplanet data leads us to conclude that hydrodynamic escape plausibly explains the observed upper limit on rocky planet size and few planets (a "valley" or "radius gap") in the 1.5-2 R  range.

show abstract

Section: Discussionmentioning

confidence: 99%

Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Lehmer

Catling

2017

ApJ

View full text Add to dashboard Cite

show abstract

“…Together with the pipeline completeness (Christiansen et al 2013(Christiansen et al , 2015, this information is needed to accurately assess the underlying occurrence of planets, down to Earth-size planets in the habitable zone. The latter is the main objective of the Kepler prime mission (Borucki et al 2009;Batalha 2014).…”

Section: Comparison With Other False-positive Rate Estimatesmentioning

confidence: 99%

SOPHIE velocimetry ofKeplertransit candidates

Santerne

Moutou

Tsantaki

et al. 2016

A&A

268

263

View full text Add to dashboard Cite

While giant extrasolar planets have been studied for more than two decades now, there are still some open questions as to their dominant formation and migration processes, as well as to their atmospheric evolution in different stellar environments. In this paper, we study a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days. We first defined a sample of 129 giant-planet candidates that we followed up with the SOPHIE spectrograph (OHP, France) in a 6-year radial velocity campaign. This allowed us to unveil the nature of these candidates and to measure a false-positive rate of 54.6 ± 6.5% for giant-planet candidates orbiting within 400 days of period. Based on a sample of confirmed or likely planets, we then derived the occurrence rates of giant planets in different ranges of orbital periods. The overall occurrence rate of giant planets within 400 days is 4.6 ± 0.6%. We recovered, for the first time in the Kepler data, the different populations of giant planets reported by radial velocity surveys. Comparing these rates with other yields, we find that the occurrence rate of giant planets is lower only for hot Jupiters but not for the longer-period planets. We also derive a first measurement of the occurrence rate of brown dwarfs in the brown-dwarf desert with a value of 0.29 ± 0.17%. Finally, we discuss the physical properties of the giant planets in our sample. We confirm that giant planets receiving moderate irradiation are not inflated, but we find that they are on average smaller than predicted by formation and evolution models. In this regime of low-irradiated giant planets, we find a possible correlation between their bulk density and the iron abundance of the host star, which needs more detections to be confirmed.

show abstract

“…The question's profundity occupies a singular place in any conception of the human relation with the cosmos. The search for life and Earth-like environments has long received a great deal of attention from astronomers, punctuated most recently by a series of discoveries that have determined conclusively that Earth-like exoplanets exist in abundance throughout our galaxy (Dressing & Charbonneau 2013;Petigura et al 2013;Batalha 2014).…”

Section: Introductionmentioning

confidence: 99%

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

Enriquez

Siemion

Foster

et al. 2017

ApJ

141

335

View full text Add to dashboard Cite

We report on a search for engineered signals from a sample of 692 nearby stars using the Robert C. Byrd Green Bank Telescope, undertaken as part of the Breakthrough Listen Initiative search for extraterrestrial intelligence. Observations were made over 1.1-1.9 GHz (L band), with three sets of five-minute observations of the 692 primary targets, interspersed with five-minute observations of secondary targets. By comparing the "ON" and "OFF" observations, we are able to identify terrestrial interference and place limits on the presence of engineered signals from putative extraterrestrial civilizations inhabiting the environs of the target stars. During the analysis, 11 events passed our thresholding algorithm, but a detailed analysis of their properties indicates that they are consistent with known examples of anthropogenic radio-frequency interference. We conclude that, at the time of our observations, none of the observed systems host high-duty-cycle radio transmitters emitting between 1.1 and 1.9 GHz with an Equivalent Isotropic Radiated Power of ∼10 13 W, which is readily achievable by our own civilization. Our results suggest that fewer than ∼0.1% of the stellar systems within 50 pc possess the type of transmitters searched in this survey.

show abstract

Exploring exoplanet populations with NASA’s Kepler Mission

Cited by 241 publications

References 93 publications

Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

SOPHIE velocimetry ofKeplertransit candidates

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

Contact Info

Product

Resources

About