Search arXiv⌕ Search

arXiv · 0912.3484

Characterizing Habitable Exo-Moons

Abstract

We discuss the possibility of screening the atmosphere of exomoons for habitability. We concentrate on Earth-like satellites of extrasolar giant planets (EGP) which orbit in the Habitable Zone of their host stars. The detectability of exomoons for EGP in the Habitable Zone has recently been shown to be feasible with the Kepler Mission or equivalent photometry using transit duration observations. Using the Earth itself as a proxy we show the potential and limits of spectroscopy to detect biomarkers on an Earth-like exomoon and discuss effects of tidal locking for such potential habitats. Transmission spectroscopy of exomoons is a unique potential tool to screen them for habitability in the near future.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

L. Kaltenegger. 2010-03-03. Characterizing Habitable Exo-Moons. https://doi.org/10.1088/2041-8205%2F712%2F2%2Fl125

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

KEEP EXPLORING

Related papers

Chondrule size averaging in two and three dimensions

Chondrule sizes are an important discriminant of chondrite groups and chondrule formation theories. Yet most studies report 2D sizes without attempting the somewhat tedious corrections to 3D proposed in the past literature. I show here that 3D size averages can be simply calculated directly from 2D averages of appropriate powers of sizes (and vice-versa), without having to reconstruct 3D distributions, although explicit formulas to that end are also provided. This illuminates the comparison between 3D and 2D arithmetic size averages, which are confirmed to be little different for the published datasets. Yet I suggest another type of average, the "sphere-weighted average" (i.e. weighted by the chondrule equal-volume sphere area), a measure of the surface/volume ratio of the chondrule population, which is more robust against omission of small chondrules. While larger than the arithmetic averages, it is best in line with previous literature estimates based on less exhaustive surveys of chondrules.

astro-ph.EP↗

A 36.34-day Sub-Neptune Candidate Transiting the Nearby K Dwarf TIC 402710280

We report a transiting sub-Neptune candidate with a period of 36.34 days around TIC 402710280 (TYC 9041-03677-1), a K dwarf of TESS magnitude 9.24 at 66.8 pc that the Transiting Exoplanet Survey Satellite (TESS) has observed only in full-frame images. Four transits, recorded between 2021 and 2026 in Sectors 39, 93, 100 and 102 and reduced by three independent pipelines, share a depth of $2092 \pm 47$ ppm and a duration of $5.27 \pm 0.05$ h. Two of them fall on consecutive cycles, and every shorter period predicts transits in covered data that are absent at $\geq 18.6σ$; the period is $P = 36.33986 \pm 0.00051$ d. A transit model gives $R_p/R_\star = 0.0421^{+0.0007}_{-0.0005}$ and a stellar density consistent with the host's. The candidate has a radius of $3.75 \pm 0.22 R_\oplus$ and an equilibrium temperature of $498 \pm 21$ K. Difference-image centroids place the signal $1.5'' \pm 1.3''$ from the target. The only catalogued star close enough to contribute, a background star $3.5''$ away, would have to host an eclipsing binary whose eclipse shape is disfavoured for any main-sequence pair ($Δχ^2 \geq 142$). No secondary eclipse is detected, and TRICERATOPS gives a false-positive probability of $0.003 \pm 0.004$. No high-resolution imaging exists, so companions within about $1''$ are constrained only by Gaia astrometry. The mid-times scatter about a linear ephemeris by 21.8 min (rms). Quick-Look Pipeline light curves reproduce the 29-min excess in the interval between the two 2026 transits, so it does not arise in our photometry; we report the scatter without choosing between an instrumental and a dynamical origin. The light curve also contains a $407 \pm 26$ ppm signal with a period of 3.78 days whose source, the target or the background star, the present data cannot identify. We predict transit times, including one in TESS Sector 114 on 2027 February 19.

astro-ph.EP↗

The EMA Justitia Probe: Terminator Frame-Based Deployment Orbit Selection and Surface Coverage Analysis

The Emirates Mission to the Asteroid Belt (EMA) probe is designed to perform asteroid imaging during an uncontrolled ballistic descent to (269) Justitia. The mission design is constrained by main spacecraft proximity operations, uncertain asteroid gravity, limited knowledge of the final deployment trajectory, and requirements for illumination and safe operations. These constraints necessitate a mission design that ensures suitable illumination, attitude determination and control, and payload pointing throughout descent. The EMA probe concept of operations employs near-terminator deployment orbit geometry with continuous Sun visibility and two attitude control modes: single-axis Sun-spin for periodic imaging opportunities and three-axis asteroid-pointing for continuous asteroid visibility. Based on these modes, formal requirements are derived for deployment orbits that enable asteroid observations during ballistic descent. A deployment orbit selection method is developed using the terminator reference frame and a minimum boresight deviation margin. The method identifies families of orbit orientations satisfying illumination and payload observation constraints. Reference orbits are selected and verified through mission geometry analysis and trajectory propagation using a polyhedron gravity model. Asteroid surface coverage is then evaluated for uncontrolled tumbling, Sun-spin, and asteroid-pointing modes. The results characterize the expected imaging performance and demonstrate the feasibility of the EMA probe concept for close-proximity asteroid imaging. The proposed approach can also support future ballistic probe missions subject to similar operational and observational constraints.

astro-ph.EP↗