Destination exoplanet: Habitability conditions influenced by stellar winds properties

Chebly, Judy; Alvarado‐Gómez, Julián D.; Poppenhaeger, Katja

doi:10.1002/asna.20210093

Cited by 5 publications

(2 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A proper understanding of the influence of the host star to the atmosphere requires the upper atmosphere and is therefore beyond the scope of this paper. This can have a major factor for the atmospheric evolution (Chen et al, 2020;Turbet and Selsis, 2021;Chebly et al, 2021;Locci et al, 2022;Teal et al, 2022). The triggered photochemistry can not only destroy pre-biotic molecules, but also enhance the formation of these as many reactions need the input of some sort of energy, this can for example be provided by the stellar irradiation (in the form of UV radiation) or lightning discharges.…”

Section: Implications For Atmospheric Biosignaturesmentioning

confidence: 99%

Habitability constraints by nutrient availability in atmospheres of rocky exoplanets

Herbort,

Woitke,

Helling

et al. 2024

International Journal of Astrobiology

View full text Add to dashboard Cite

Life as we know it requires the presence of liquid water and the availability of nutrients, which are mainly based on the elements C, H, N, O, P and S (CHNOPS) and trace metal micronutrients. We aim to understand the presence of these nutrients within atmospheres that show the presence of water cloud condensates, potentially allowing the existence of aerial biospheres. In this paper, we introduce a framework of nutrient availability levels based on the presence of water condensates and the chemical state of the CHNOPS elements. These nutrient availability levels are applied to a set of atmospheric models based on different planetary surface compositions resulting in a range of atmospheric compositions. The atmospheric model is a bottom-to-top equilibrium chemistry atmospheric model which includes the atmosphere–crust interaction and the element depletion due to the formation of clouds. While the reduced forms of CNS are present at the water cloud base for most atmospheric compositions, P and metals are lacking. This indicates the potential bio-availability of CNS, while P and metals are limiting factors for aerial biospheres.

show abstract

Section: Implications For Atmospheric Biosignaturesmentioning

confidence: 99%

Habitability constraints by nutrient availability in atmospheres of rocky exoplanets

Herbort,

Woitke,

Helling

et al. 2024

International Journal of Astrobiology

View full text Add to dashboard Cite

show abstract

“…However, M-type stars are prone to high levels of stellar activity (Walkowicz et al 2011;Loyd et al 2016Loyd et al , 2018b) that can impact the radial velocity and/or transit signal of such systems through phenomena such as flaring (Tofflemire et al 2012), star spots, plages and faculae (Boisse et al 2011;Llama & Shkolnik 2015;Cauley et al 2018;Roettenbacher et al 2022;Bruno et al 2022), and other activity-induced variability (Dumusque 2018;Rackham et al 2019;Bellotti et al 2022;Collier Cameron et al 2021). Aside from the observational implications, the planet's physical and chemical state can be altered by stellar activity as well due to, for example, coronal mass ejections (CMEs) and stellar particle events (SPEs) (Yamashiki et al 2019;Atri 2017Atri , 2020Segura et al 2010), winds (Vidotto et al 2015;Vidotto & Cleary 2020;Chebly et al 2022;Colombo et al 2022), and stellar flares (Segura et al 2010;Venot et al 2016;Chadney et al 2017;Tilley et al 2019;Chen et al 2021;Louca et al 2022), the latter being sudden releases of radiative energy triggered by magnetic reconnection (Benz & Güdel 2010). Stellar flares result in a temporary increase in incident flux on the planet's atmosphere, which in turn increases the photochemical reaction rates that can change the chemical composition.…”

Section: Introductionmentioning

confidence: 99%

Impact of stellar flares on the chemical composition and transmission spectra of gaseous exoplanets orbiting M dwarfs

Konings

Baeyens

Decin

2022

A&A

View full text Add to dashboard Cite

Context. Stellar flares of active M dwarfs can affect the atmospheric composition of close-orbiting gas giants, and can result in time-dependent transmission spectra. Aims. We aim to examine the impact of a variety of flares, differing in energy, duration, and occurrence frequency, on the composition and transmission spectra of close-orbiting, tidally locked gaseous planets with climates dominated by equatorial superrotation. Methods. We used a series of pseudo-2D photo-and thermochemical kinetics models, which take advection by the equatorial jet stream into account, to simulate the neutral molecular composition of a gaseous planet (T eff = 800 K) that orbits a M dwarf during artificially constructed flare events. We then computed transmission spectra for the evening and morning limb. Results. We find that the upper regions (i.e. below 10 µbar) of the dayside and evening limb are heavily depleted in CH 4 and NH 3 up to several days after a flare event with a total radiative energy of 2 × 10 33 erg. Molar fractions of C 2 H 2 and HCN are enhanced up to a factor three on the nightside and morning limb after day-to-nightside advection of photodissociated CH 4 and NH 3 . Methane depletion reduces transit depths by 100-300 parts per million (ppm) on the evening limb and C 2 H 2 production increases the 14 µm feature up to 350 ppm on the morning limb. We find that repeated flaring drives the atmosphere to a composition that differs from its pre-flare distribution and that this translates to a permanent modification of the transmission spectrum. Conclusions. We show that single high-energy flares can affect the atmospheres of close-orbiting gas giants up to several days after the flare event, during which their transmission spectra are altered by several hundred ppm. Repeated flaring has important implications for future retrieval analyses of exoplanets around active stars, as the atmospheric composition and resulting spectral signatures substantially differ from models that do not include flaring.

show abstract

Numerical quantification of the wind properties of cool main sequence stars

Chebly

Alvarado‐Gómez

Poppenhäger

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

As a cool star evolves, it loses mass and angular momentum due to magnetized stellar winds which affect its rotational evolution. This change has consequences that range from the alteration of its activity to influences over the atmosphere of any orbiting planet. Despite their importance, observations constraining the properties of stellar winds in cool stars are extremely limited. Therefore, numerical simulations provide a valuable way to understand the structure and properties of these winds. In this work, we simulate the magnetized winds of 21 cool main-sequence stars (F-type to M-dwarfs), using a state-of-the-art 3D MHD code driven by observed large-scale magnetic field distributions. We perform a qualitative and quantitative characterization of our solutions, analyzing the dependencies between the driving conditions (e.g., spectral type, rotation, magnetic field strength) and the resulting stellar wind parameters (e.g., Alfvén surface size, mass loss rate, angular momentum loss rate, stellar wind speeds). We compare our models with the current observational knowledge on stellar winds in cool stars and explore the behaviour of the mass loss rate as a function of the Rossby number. Furthermore, our 3D models encompass the entire classical Habitable Zones (HZ) of all the stars in our sample. This allows us to provide the stellar wind dynamic pressure at both edges of the HZ and analyze the variations of this parameter across spectral type and orbital inclination. The results here presented could serve to inform future studies of stellar wind-magnetosphere interactions and stellar wind erosion of planetary atmospheres via ion escape processes.

show abstract

Destination exoplanet: Habitability conditions influenced by stellar winds properties

Cited by 5 publications

References 39 publications

Habitability constraints by nutrient availability in atmospheres of rocky exoplanets

Habitability constraints by nutrient availability in atmospheres of rocky exoplanets

Impact of stellar flares on the chemical composition and transmission spectra of gaseous exoplanets orbiting M dwarfs

Numerical quantification of the wind properties of cool main sequence stars

Contact Info

Product

Resources

About