Effects of flares on the habitable zones of M dwarfs accessible to TESS planet detections

AbstractCARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a new instrument currently undergoing commissioning at the 3.5 m telescope of the Calar Alto Observatory. It has been constructed by a consortium of eleven Spanish and German institutions. The scientific goal of the project is a 600-night radial-velocity survey targeting 300 M dwarfs with sufficient precision to detect terrestrial planets in their habitable zones. The CARMENES instrument consists of two separate échelle spectrographs covering the wavelength range from 0.55 to 1.7 μm at a spectral resolution of R = 82,000, fed by fibers from the Cassegrain focus of the telescope. Both spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a long-term radial velocity precision of 1 m s−1. The wavelength calibration will be done with Th-Ne and U-Ne emission line lamps, and with Fabry-Pérot etalons.

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Detection of O2 Produced Abiotically on Habitable but Lifeless Planets around M-dwarfs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313012507 ◽

2012 ◽

Vol 8 (S293) ◽

pp. 39-45 ◽

Cited By ~ 3

Author(s):

Tong Li ◽

Feng Tian

Keyword(s):

Radiative Transfer ◽

Molecular Oxygen ◽

Uv Spectra ◽

Radiative Transfer Model ◽

Transfer Model ◽

Hitran Database ◽

M Dwarfs ◽

Near Ir ◽

Habitable Zones ◽

Near Ir Range

AbstractHigh atmospheric abundances of oxygen has been widely considered to be a reliable biosignature for life on exoplanets in the habitable zones of all types of stars. Recently it was proposed that the unique UV spectra of observed planet-hosting M dwarfs could lead to the buildup of molecular oxygen in the atmospheres of habitable but lifeless planets around these stars (Tian et al. 2014). However, the detectability of the accumulated O2 was not modeled. In this work we developed a new line by line radiative transfer model based on HITRAN database and used the model to simulate the reflectivity in the visible and near IR range. We show that abiotically produced and maintained O2 in the 0.2% level is observable at 13105 cm−1 (0.76 μm) with the spectra resolution of 70.

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Formation of terrestrial planets from planetesimals around M dwarfs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308016748 ◽

2007 ◽

Vol 3 (S249) ◽

pp. 305-308

Author(s):

Masahiro Ogihara ◽

Shigeru Ida

Keyword(s):

Terrestrial Planet ◽

Terrestrial Planets ◽

Type I ◽

M Dwarfs ◽

Mean Motion Resonances ◽

Mean Motion ◽

Habitable Zones ◽

Pile Up ◽

Solar Type ◽

Water Contents

AbstractWe have investigated accretion of terrestrial planets from planetesimals around M dwarfs through N-body simulations including the effect of tidal interaction with disk gas. Because of low luminosity of M dwarfs, habitable zones around them are located near the disk inner edge. Planetary embryos undergo type-I migration and pile up near the disk inner edge. We found that after repeated close scatterings and occasional collisions, three or four planets eventually remain in stable orbits in their mean motion resonances. Furthermore, large amount of water-rich planetesimals rapidly migrate to the terrestrial planet regions from outside of the snow line, so that formed planets in these regions have much more water contents than those around solar-type stars.

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Atmospheric Parameters and Luminosities of Nearby M Dwarfs – Estimating Habitable Exoplanet Detectability with the E-ELT

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317003696 ◽

2016 ◽

Vol 12 (S328) ◽

pp. 371-373

Author(s):

Gustavo F. Porto de Mello ◽

Riano E. Giribaldi ◽

Diego Lorenzo-Oliveira ◽

Nathália M. Paes Leme

Keyword(s):

Spectral Line ◽

Detailed Analysis ◽

Atmospheric Parameters ◽

M Dwarfs ◽

Habitable Zones ◽

Pca Method ◽

Rocky Planets

AbstractWe derive Teff and [Fe/H] for a sample of 72 nearby M-dwarfs with Hipparcos parallaxes and δ < +30. Spectra, acquired at the Observatório do Pico dos Dias, Brazil, have R = 10,000 and S/N ≳ 100 for nearly all targets in the λλ8380-8880 range. Atmospheric parameters were derived from VJHK colors and a system of spectral line indices calibrated against sample stars with interferometric Teff and [Fe/H] from detailed analysis of FGK binary companions. A PCA method of calibration yields internal errors within 70 K and 0.1 dex for Teff and [Fe/H]. For 18 stars we present the first Teff or [Fe/H] derivation in the literature. We compute the star's luminosities, calculate the position of their habitable zones and estimate that, were all of they to harbour rocky planets inside their HZ, 15–20 of these would be detectable by the E-ELT Planetary Camera and Spectrograph.

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Exosphere Modeling of Proxima b: A Case Study of Photochemical Escape with a Venus-like Atmosphere

The Astrophysical Journal ◽

10.3847/1538-4357/ac26bb ◽

2021 ◽

Vol 923 (2) ◽

pp. 190

Author(s):

Yuni Lee ◽

Chuanfei Dong ◽

Valeriy Tenishev

Keyword(s):

Dynamic Pressure ◽

Dissociative Recombination ◽

Monte Carlo Code ◽

M Dwarfs ◽

Habitable Zones ◽

Order Of Magnitude ◽

Global Magnetic Field ◽

Corona Structure ◽

Hot Oxygen

Abstract Exoplanets orbiting M dwarfs within habitable zones are exposed to stellar environments more extreme than that terrestrial planets experience in our solar system, which can significantly impact the atmospheres of the exoplanets and affect their habitability and sustainability. This study provides the first prediction of hot oxygen corona structure and the associated photochemical loss from a 1 bar CO2-dominated atmosphere of a Venus-like rocky exoplanet, where dissociative recombination of O2 + ions is assumed to be the major source reaction for the escape of neutral O atoms and formation of the hot O corona (or exospheres) as on Mars and Venus. We employ a 3D Monte Carlo code to simulate the exosphere of Proxima Centauri b (PCb) based on the ionosphere simulated by a 3D magnetohydrodynamic model. Our simulation results show that variability of the stellar wind dynamic pressure over one orbital period of PCb does not affect the overall spatial structure of the hot O corona but contributes to the change in the global hot O escape rate that varies by an order of magnitude. The escape increases dramatically when the planet possesses its intrinsic magnetic fields as the ionosphere becomes more extended with the presence of a global magnetic field. The extended hot O corona may lead to a more extended H exosphere through collisions between thermal H and hot O, which exemplifies the importance of considering nonthermal populations in exospheres to interpret future observations.

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Habitable Evaporated Cores: Transforming Mini-Neptunes into Super-Earths in the Habitable Zones of M Dwarfs

Astrobiology ◽

10.1089/ast.2014.1215 ◽

2015 ◽

Vol 15 (1) ◽

pp. 57-88 ◽

Cited By ~ 79

Author(s):

R. Luger ◽

R. Barnes ◽

E. Lopez ◽

J. Fortney ◽

B. Jackson ◽

...

Keyword(s):

M Dwarfs ◽

Habitable Zones

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The CARMENES Survey: A Search for Terrestrial Planets in the Habitable Zones of M Dwarfs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313012787 ◽

2012 ◽

Vol 8 (S293) ◽

pp. 177-182

Author(s):

A. Quirrenbach ◽

P. J. Amado ◽

J. A. Caballero ◽

H. Mandel ◽

R. Mundt ◽

...

Keyword(s):

Radial Velocity ◽

Emission Line ◽

Spectral Resolution ◽

M Dwarfs ◽

Habitable Zones ◽

Scientific Goal ◽

M Stars ◽

Under Construction ◽

Calar Alto

AbstractCARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument under construction for the 3.5 m telescope at the Calar Alto Observatory by a consortium of eleven Spanish and German institutions. The scientific goal of the project is a five-year exoplanet survey targeting 300 M stars with the completed instrument. The CARMENES hardware consists of two separate échelle spectrographs covering the wavelength range from 0.55 to 1.7 μm at a spectral resolution of R = 82,000, fed by fibers from the Cassegrain focus of the telescope. Both spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a long-term radial velocity precision of 1 m s−1 employing a simultaneous calibration with Th-Ne and U-Ne emission line lamps.

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First Study of Photochemical Escape from Proxima Centauri b

10.5194/epsc2020-888 ◽

2020 ◽

Author(s):

Yuni Lee ◽

Chuanfei Dong

Keyword(s):

Extreme Environments ◽

Adaptive Mesh ◽

Neutral Atmosphere ◽

M Dwarfs ◽

Model Framework ◽

Habitable Zones ◽

Solar System Bodies ◽

Mhd Model ◽

Atmospheric Loss ◽

First Time

As the upper atmospheres of the &#8216;habitable&#8217; exoplanets orbiting M-Dwarfs are affected by more extreme environments than what Solar System bodies experience, the observations of such exoplanets raise questions to the mass-loss mechanisms and the sustainability of their atmospheres. For the first time, we examine the loss of neutral atmosphere from Proxima Centauri b (PCb) via photochemical mechanisms and formation processes of resulting exoplanetary hot atomic coronae or exospheres. The study is conducted by utilizing our integrated model framework, which couples our 3D Adaptive Mesh Particle Simulator (AMPS) for planetary exospheres and a 3D multi-species magnetohydrodynamic (MHD) model originally developed for Venus and Mars. The coupling of the two models is achieved in one-way, such that the AMPS code incorporates pre-simulated results by the MHD model as inputs for exosphere simulation. The MHD model describes the ionosphere of the planet self-consistently based on the neutral atmosphere adopted for PCb. All simulations in this study assume a Venus-like condition for the ionosphere and thermosphere of PCb, which is also based on an assumption of the absence of an intrinsic dipole magnetic field. As most of the relevant planetary parameters of PCb are unknown, this study provides one possible interpretation of the atmospheric loss process of PCb as well as other exoplanets similar to PCb, which reside in the Habitable Zones (HZs) of M-Dwarfs, to help our understanding of their habitability. &#160;

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CARMENES input catalogue of M dwarfs

Astronomy and Astrophysics ◽

10.1051/0004-6361/201629599 ◽

2018 ◽

Vol 614 ◽

pp. A76 ◽

Cited By ~ 36

Author(s):

S. V. Jeffers ◽

P. Schöfer ◽

A. Lamert ◽

A. Reiners ◽

D. Montes ◽

...

Keyword(s):

High Resolution ◽

Radial Velocity ◽

Activity Index ◽

Rotation Velocity ◽

M Dwarfs ◽

Multiple Observations ◽

Habitable Zones ◽

High Resolution Analysis ◽

Resolution Analysis ◽

Host Stars

CARMENES is a spectrograph for radial velocity surveys of M dwarfs with the aim of detecting Earth-mass planets orbiting in the habitable zones of their host stars. To ensure an optimal use of the CARMENES guaranteed time observations, in this paper we investigate the correlation of activity and rotation for approximately 2200 M dwarfs, ranging in spectral type from M0.0 V to M9.0 V. We present new high-resolution spectroscopic observations with FEROS, CAFE, and HRS of approximately 500 M dwarfs. For each new observation, we determined its radial velocity and measured its Hα activity index and its rotation velocity. Additionally, we have multiple observations of many stars to investigate if there are any radial velocity variations due to multiplicity. The results of our survey confirm that early-M dwarfs are Hα inactive with low rotational velocities and that late-M dwarfs are Hα active with very high rotational velocities. The results of this high-resolution analysis comprise the most extensive catalogue of rotation and activity in M dwarfs currently available.

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