![Dereddened Gaia CMD with PARSEC isochrones overplotted. Black points show Gaia DR3 stars corrected for extinction and reddening using band-specific coefficients. Solid curves show isochrones spanning ages from 1 to 13 Gyr at the reference metallicity. The dotted curves highlight 1 Gyr isochrones computed at the lower (-0.4 dex) and upper (+0.4 dex) metallicity values in the sample, illustrating the range of CMD permitted by the observed metallicity distribution. This comparison demonstrates the impact of metallicity on isochrone placement relative to the data. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Precise.png?resize=1200%2C718&ssl=1)
[astro-ph.EP] Accurate stellar ages are fundamental to interpreting the evolutionary histories of habitable zone (HZ) planets. Because stellar luminosity evolves over time, HZ boundaries migrate outward, meaning that present-day HZ […]
Stellar Cartography
![Cumulative oxygen loss for planets at the habitable zone of each sample star over 1 Gyr, assuming constant stellar XUV flux at the HZ and no replenishment of oxygen. The curves are calculated using the energy-limited O2 loss prescription from V. S. Airapetian et al. 2017. Colored lines show individual stars, with solid segments representing the earliest ages (for stars with age ranges) and dashed segments extending beyond the minimum age. The black solid line shows the solar reference. Horizontal lines indicate the present-day Earth atmospheric O2 content (∼0.2 bars; dotted) and the total mass of Earth’s oceans (∼240 bars; dashed), providing reference levels for planetary habitability. -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Panchromatic.png?resize=1200%2C720&ssl=1)
Posted inHabitable Zones
Panchromatic Spectra of Nearby Low-mass and Sun-like Stars with Directly Imageable Habitable Zones
[astro-ph.SR] Characterizing the high-energy radiation environments of stars plays a critical role in determining which systems’ planets are capable of retaining atmospheres and sustaining habitable conditions.
Posted inExoplanets, -moons, -comets
Hidden Worlds: A Non-transiting Candidate Planet In The Neptunian Desert Around The Solar-type Pulsator KIC 9139163
[Astronomy & Astrophysics] Close-in substellar companions experience strong tidal and magnetic interactions with their host stars and are therefore subject to fast orbital evolution.
Posted inExoplanets, -moons, -comets
Pandora Mission Begins A Study Of Exoplanets And Their Host Stars
[NASA] Pandora, NASA’s newest exoplanet mission and the first satellite to launch through the agency’s Astrophysics Pioneers program, is now making unique observations of worlds beyond our solar system and […]
![Sunburst diagrams describing the evolution of the inner planets (top) and the outer giant planets (bottom) in the DAG simulations. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Effects-of.png?resize=1200%2C717&ssl=1)
Posted inExoplanets, -moons, -comets
Effects Of Outer Giant Planets On In Situ Formation Of Inner Super-Earths
[astro-ph.EP] Recent studies have found an observational correlation between the presence of outer giant planets and inner super-Earths, which implies that outer giants do not suppress the formation of super-Earths.
Posted inExoplanets, -moons, -comets
Astro-Hunters: Machine Learning For Exoplanet Transit Detection In TESS Photometry
[astro-ph.EP] Finding planets beyond the Solar System is now largely a data-analysis problem: photometric surveys return far more stellar light curves than can be inspected by eye, and machine learning […]
![Chemical abundance distributions of the Sample II planet-candidate host stars in the [Fe/H]–[Mg/Fe] plane.](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/A-chemo.png?resize=1200%2C715&ssl=1)
Posted inStellar Cartography
A Chemo-dynamical Search For Planet-candidate Hosts Of Possible Extragalactic Origin
[astro-ph.SR] To date, all known exoplanetary systems have been identified around stars currently residing in the Milky Way, whereas planets formed in external galaxies remain largely unexplored. Such systems would […]
Posted inHabitable Zones
Planetary Stability and Long-Term Habitability in Nearby Stellar Binaries: 70 Oph, 36 Oph, γ Leo
[astro-ph.EP] Binary stars are common and have the potential to host habitable planets, which may reside in more complex habitable zones as compared to planets orbiting single stars.
![Left panel: Toomre diagram for the stars in our sample, color-coded by the TD/D value. Right panel: cumulative distribution function (CDF) of the TD/D values for stars with planetary systems classified into different categories. A system with at least one planet pair that is identified as plausible 1st-order (2nd-order) resonance by HS24 is labeled “w/ 1st MMR” (“w/ 2nd MMR”). The category, “w/ 1st MMR & Pin < 3 d”, corresponds approximately to the stars with plausibly 1st-order resonant and tidal decay timescale τe < 20 Myr in HS24. “USP” is the sample of planetary systems hosting ultra-short-period planets as identified in Schmidt et al. (2024).-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Are-Near.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
Are Near Resonant Multiple-planet Systems From Kepler Young?
[astro-ph.EP] Recent studies have claimed that Kepler multi-planet systems hosting near-resonant planet pairs—particularly those near second-order mean-motion resonances (MMRs)—exhibit smaller stellar velocity dispersions than the general population of Kepler planet […]
![CH Ind timing and inference. Top: the six differential nodes 𝐷 from equation (1); subtracting primary and secondary O–C values removes their common ephemeris or LTTE trend and isolates the first-order apsidal signal. Bottom: Monte Carlo posteriors for the displayed 0.08-dex common log 𝑘2 systematic; horizontal segments show central 68 per cent intervals.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Stellar-Tidal.png?resize=1200%2C718&ssl=1)
Posted inStellar Cartography
Stellar Tidal Systematics In Apsidal-motion Searches For Circumbinary Planets: CH Ind And SW CMa
[astro-ph.EP] Thornton et al. (2026) reported 27 non-transiting circumbinary-planet candidates from excess apsidal motion in TESS eclipsing-binary timings. The classical stellar contribution is sensitive to target-specific radii, apsidal constants k2, […]