Flares from ultracool L dwarfs with Kepler

AbstractWe report on our search for L dwarf flares using NASA's Kepler mission. Spectroscopically confirmedflares were detected with the original Kepler mission from an L1 dwarf stars. We discuss the physicalcharacteristics of these white light flares and compare them to M dwarf flares. For “habitable zone” planets, the apparent flare brightnesses would be comparable to the most powerful M dwarf flares. Weare monitoring more L dwarfs with the Kepler K2 mission. We discussthe prospect for more detections during the remainder of the K2 mission.

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An Astrobiological Experiment to Explore the Habitability of Tidally Locked M-Dwarf Planets

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313012817 ◽

2012 ◽

Vol 8 (S293) ◽

pp. 192-196

Author(s):

Daniel Angerhausen ◽

Haley Sapers ◽

Eugenio Simoncini ◽

Stefanie Lutz ◽

Marcelo da Rosa Alexandre ◽

...

Keyword(s):

Academic Research ◽

Environmental Parameters ◽

Climate Simulation ◽

Habitable Zone ◽

Dwarf Stars ◽

Dwarf Planets ◽

Late Type Star ◽

M Dwarf Stars ◽

M Dwarf ◽

Simulation Chamber

AbstractWe present a summary of a three-year academic research proposal drafted during the Sao Paulo Advanced School of Astrobiology (SPASA) to prepare for upcoming observations of tidally locked planets orbiting M-dwarf stars. The primary experimental goal of the suggested research is to expose extremophiles from analogue environments to a modified space simulation chamber reproducing the environmental parameters of a tidally locked planet in the habitable zone of a late-type star. Here we focus on a description of the astronomical analysis used to define the parameters for this climate simulation.

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The habitability of stagnant-lid Earths around dwarf stars

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834658 ◽

2019 ◽

Vol 625 ◽

pp. A12 ◽

Cited By ~ 8

Author(s):

Mareike Godolt ◽

Nicola Tosi ◽

Barbara Stracke ◽

John Lee Grenfell ◽

Thomas Ruedas ◽

...

Keyword(s):

Water Loss ◽

Main Sequence ◽

Extrasolar Planets ◽

Water Reservoir ◽

Habitable Zone ◽

High Luminosity ◽

Dwarf Stars ◽

Surface Conditions ◽

M Dwarf Stars ◽

M Dwarf

Context. The habitability of a planet depends on various factors, such as the delivery of water during its formation, the co-evolution of the interior and the atmosphere, and the stellar irradiation which changes in time. Aims. Since an unknown number of rocky extrasolar planets may operate in a one-plate convective regime, i.e. without plate tectonics, our aim is to understand the conditions under which planets in such a stagnant-lid regime may support habitable surface conditions. Understanding the interaction of the planetary interior and outgassing of volatiles in combination with the evolution of the host star is crucial to determining the potential habitability. M-dwarf stars in particular possess a high-luminosity pre-main sequence phase that endangers the habitability of planets around them via water loss. We therefore explore the potential of secondary outgassing from the planetary interior to rebuild a water reservoir allowing for habitability at a later stage. Methods. We compute the boundaries of the habitable zone around M-, K-, G-, and F-dwarf stars using a 1D cloud-free radiative-convective climate model accounting for the outgassing history of CO2 and H2O from an interior evolution and outgassing model for different interior compositions and stellar luminosity evolutions. Results. The outer edge of the habitable zone strongly depends on the amount of CO2 outgassed from the interior, while the inner edge is mainly determined via the stellar irradiation, as soon as a sufficiently large water reservoir has been outgassed. A build-up of a secondary surface and atmospheric water reservoir for planets around M-dwarf stars is possible even after severe water loss during the high-luminosity pre-main sequence phase as long as some water has been retained within the mantle. For small mantle water reservoirs, between 62 and 125 ppm, a time delay in outgassing from the interior permits such a secondary water reservoir build-up especially for early and mid-M dwarfs because their pre-main sequence lifetimes are shorter than the outgassing timescale. Conclusions. We show that Earth-like stagnant-lid planets allow for habitable surface conditions within a continuous habitable zone that is dependent on interior composition. Secondary outgassing from the interior may allow for habitability of planets around M-dwarf stars after severe water loss during the high-luminosity pre-main sequence phase by rebuilding a surface water reservoir.

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Why do we find ourselves around a yellow star instead of a red star?

International Journal of Astrobiology ◽

10.1017/s1473550417000118 ◽

2017 ◽

Vol 17 (1) ◽

pp. 77-86 ◽

Cited By ~ 17

Author(s):

Jacob Haqq-Misra ◽

Ravi Kumar Kopparapu ◽

Eric T. Wolf

Keyword(s):

Bayesian Inference ◽

Habitable Zone ◽

M Dwarfs ◽

Dwarf Stars ◽

Habitable Planets ◽

Chance Event ◽

The Future ◽

M Dwarf Stars ◽

M Dwarf

AbstractM-dwarf stars are more abundant than G-dwarf stars, so our position as observers on a planet orbiting a G-dwarf raises questions about the suitability of other stellar types for supporting life. If we consider ourselves as typical, in the anthropic sense that our environment is probably a typical one for conscious observers, then we are led to the conclusion that planets orbiting in the habitable zone of G-dwarf stars should be the best place for conscious life to develop. But such a conclusion neglects the possibility that K-dwarfs or M-dwarfs could provide more numerous sites for life to develop, both now and in the future. In this paper we analyse this problem through Bayesian inference to demonstrate that our occurrence around a G-dwarf might be a slight statistical anomaly, but only the sort of chance event that we expect to occur regularly. Even if M-dwarfs provide more numerous habitable planets today and in the future, we still expect mid G- to early K-dwarfs stars to be the most likely place for observers like ourselves. This suggests that observers with similar cognitive capabilities as us are most likely to be found at the present time and place, rather than in the future or around much smaller stars.

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Response of Atmospheric Biomarkers to NOx-Induced Photochemistry Generated by Stellar Cosmic Rays for Earth-like Planets in the Habitable Zone of M Dwarf Stars

Astrobiology ◽

10.1089/ast.2011.0682 ◽

2012 ◽

Vol 12 (12) ◽

pp. 1109-1122 ◽

Cited By ~ 39

Author(s):

John Lee Grenfell ◽

Jean-Mathias Grießmeier ◽

Philip von Paris ◽

A. Beate C. Patzer ◽

Helmut Lammer ◽

...

Keyword(s):

Cosmic Rays ◽

Habitable Zone ◽

Dwarf Stars ◽

Earth Like Planets ◽

M Dwarf Stars ◽

M Dwarf

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The SOPHIE search for northern extrasolar planets

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832732 ◽

2018 ◽

Vol 618 ◽

pp. A103 ◽

Cited By ~ 11

Author(s):

M. J. Hobson ◽

R. F. Díaz ◽

X. Delfosse ◽

N. Astudillo-Defru ◽

I. Boisse ◽

...

Keyword(s):

Radial Velocity ◽

Extrasolar Planets ◽

Habitable Zone ◽

Minimum Mass ◽

Velocity Measurements ◽

High Eccentricity ◽

Dwarf Stars ◽

M Stars ◽

M Dwarf Stars ◽

M Dwarf

We report the detection of two exoplanets and a further tentative candidate around the M-dwarf stars Gl96 and Gl617A, based on radial velocity measurements obtained with the SOPHIE spectrograph at the Observatoire de Haute-Provence. Both stars were observed in the context of the SOPHIE exoplanet consortium’s dedicated M-dwarf subprogramme, which aims to detect exoplanets around nearby M-dwarf stars through a systematic survey. For Gl96 we present the discovery of a new exoplanet at 73.9 d with a minimum mass of 19.66 earth masses. Gl96 b has an eccentricity of 0.44, placing it among the most eccentric planets orbiting M stars. For Gl617A we independently confirm a recently reported exoplanet at 86.7 d with a minimum mass of 31.29 earth masses. Both Gl96 b and Gl617A b are potentially within the habitable zone, although the high eccentricity of Gl96 b may take it too close to the star at periapsis.

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Finding Earth-size planets in the habitable zone: theKepler Mission

Proceedings of the International Astronomical Union ◽

10.1017/s174392130801630x ◽

2007 ◽

Vol 3 (S249) ◽

pp. 17-24 ◽

Cited By ~ 8

Author(s):

William Borucki ◽

David Koch ◽

Gibor Basri ◽

Natalie Batalha ◽

Timothy Brown ◽

...

Keyword(s):

Field Of View ◽

Mission Design ◽

Habitable Zone ◽

Analysis Pipeline ◽

Dwarf Stars ◽

Astrophysical Data ◽

Kepler Mission ◽

Single Field ◽

Data Program

AbstractTheKepler Missionis a space-based mission whose primary goal is to detect Earth-size and smaller planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for transits with a differential photometric precision of 20 ppm at V=12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.This overview describes the mission design, its goals and capabilities, the measured performance for those photometer components that have now been tested, the Kepler Input Catalog, an overview of the analysis pipeline, the plans for the Follow-up Observing Program to validate the detections and characterize the parent stars, and finally, the plans for the Guest Observer and Astrophysical Data Program.

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Sensitivity of biosignatures on Earth-like planets orbiting in the habitable zone of cool M-dwarf Stars to varying stellar UV radiation and surface biomass emissions

Planetary and Space Science ◽

10.1016/j.pss.2013.10.006 ◽

2014 ◽

Vol 98 ◽

pp. 66-76 ◽

Cited By ~ 35

Author(s):

J.L. Grenfell ◽

S. Gebauer ◽

P. v. Paris ◽

M. Godolt ◽

H. Rauer

Keyword(s):

Uv Radiation ◽

Habitable Zone ◽

Dwarf Stars ◽

Earth Like Planets ◽

M Dwarf Stars ◽

M Dwarf

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KEPLER: Search for Earth-Size Planets in the Habitable Zone

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308026513 ◽

2008 ◽

Vol 4 (S253) ◽

pp. 289-299 ◽

Cited By ~ 25

Author(s):

William Borucki ◽

David Koch ◽

Natalie Batalha ◽

Douglas Caldwell ◽

Jorgen Christensen-Dalsgaard ◽

...

Keyword(s):

Field Of View ◽

Habitable Zone ◽

Dwarf Stars ◽

Astrophysical Data ◽

Short Overview ◽

Kepler Mission ◽

History Of ◽

Single Field

AbstractThe Kepler Mission is a space-based mission whose primary goal is to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for patterns of transits with a differential photometric precision of 20 ppm at V = 12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.This paper provides a short overview of the mission, a brief history of the mission development, expected results, new investigations by the recently chosen Participating Scientists, and the plans for the Guest Observer and Astrophysical Data Programs.

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On the abundance of extraterrestrial life after the Kepler mission

International Journal of Astrobiology ◽

10.1017/s1473550414000767 ◽

2015 ◽

Vol 14 (3) ◽

pp. 511-516 ◽

Cited By ~ 12

Author(s):

Amri Wandel

Keyword(s):

Significant Fraction ◽

Habitable Zone ◽

Radio Telescopes ◽

Extraterrestrial Life ◽

Space Density ◽

Astronomical Data ◽

Unknown Probability ◽

Kepler Mission ◽

Average Longevity ◽

Electromagnetic Signals

AbstractThe data recently accumulated by the Kepler mission have demonstrated that small planets are quite common and that a significant fraction of all stars may have an Earth-like planet within their habitable zone. These results are combined with a Drake-equation formalism to derive the space density of biotic planets as a function of the relatively modest uncertainty in the astronomical data and of the (yet unknown) probability for the evolution of biotic life, Fb. I suggest that Fb may be estimated by future spectral observations of exoplanet biomarkers. If Fb is in the range 0.001–1, then a biotic planet may be expected within 10–100 light years from Earth. Extending the biotic results to advanced life I derive expressions for the distance to putative civilizations in terms of two additional Drake parameters – the probability for evolution of a civilization, Fc, and its average longevity. For instance, assuming optimistic probability values (Fb~Fc~1) and a broadcasting longevity of a few thousand years, the likely distance to the nearest civilizations detectable by searching for intelligent electromagnetic signals is of the order of a few thousand light years. The probability of detecting intelligent signals with present and future radio telescopes is calculated as a function of the Drake parameters. Finally, I describe how the detection of intelligent signals would constrain the Drake parameters.

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