Stellar Cartography Archives

A KDE plot of SPOCK Stability vs. Eccentricity for KOI-82 on the left and KOI-70 on the right. Color denotes the density of samples. The KDE is normalized with 1 being the highest density of points for the system and 0 being the lowest density of points for the system. A small range of possible eccentricities for a specific stability are denoted by a lighter colored area, while a large range of possible eccentricities for a specific stability are denoted by a darker colored area. As eccentricity increases, stability decreases. Note how there are two well constrained regions of stability and instability with a transition region between the two. The eccentricity that describes the location of this transition region, as marked by a SPOCK Stability of 50%, we called the ”characteristic” eccentricity of the system. -- astro-ph.EP

From Stability to Instability: Characterizing the Eccentricities of Multi-planet Systems in the California Kepler Survey as a Means of Studying Stability

by Keith CowingJanuary 14, 2025January 14, 2025

Understanding the stability of exoplanet systems is crucial for constraining planetary formation and evolution theories.

X-ray images of the GJ 644/GJ 643 system from ROSAT RASS (top left), ROSAT HRI (top right), XMM-Newton EPIC (bottom left), and Chandra ACIS (bottom right). The circles are around the stellar positions extrapolated back to the epoch of the respective observations and have a radius of 15" -- astro-ph.SR

Exoplanets, -moons, -comets, Habitable Zones, Radiation, Space Weather & Heliophysics, Status Report, Stellar Cartography

X-ray Activity Of Nearby G-, K-, And M-type Stars And Implications for Planet Habitability Around M stars

by Keith CowingJanuary 14, 2025January 14, 2025

Context. The intense X-ray and UV emission of some active M stars has raised questions about the habitability of planets around M-type stars. Aims. We aim to determine the unbiased […]

125 flares discovered in CM Draconis, stacked together and aligned to have a peak at 𝑡 = 0.

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Proxima Centauri, Radiation, Space Weather & Heliophysics, Status Report, Stellar Cartography, TRAPPIST-1

Identifying Flare Locations Through Exoplanet Transit Occultations

by Keith CowingJanuary 11, 2025

M dwarfs are the most common stars in the galaxy, with long lifespans, a high occurrence rate of rocky planets, and close-in habitable zones.

Brightness distribution of the 13CO J=2−1 lines integrated over the velocity interval corresponding to the full width at zero intensity of the C18O J=2−1 lines. The contours show levels at 3, 5, 10, and 20 times the root mean square noise level of the image. -- astro-ph.SR

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Interstellar, Status Report, Stellar Cartography

ALMA Observations of CO Isotopologues Towards Six Obscured post-AGB Stars

by Keith CowingJanuary 9, 2025January 9, 2025

Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB), when an efficient mass-loss process removes a significant fraction of their initial mass.

LEFT: Evolution in the period ratios plane. The points are colour-coded according to their time before the close encounter. We note that the system spends almost all of its time very close to its starting location. Green oblique lines correspond the loci of the zeroth-order threeplanet MMRs. The first-order two-planet MMRs, 7:6 and 6:5, are plotted in grey. The second-order resonance 13:11 is plotted in red. Adapted from Petit et al. (2020). RIGHT: Number of resonances covering the period ratios space for equal-mass planets, with masses 10−5 M⊙. At first order, the number of resonances can be compared to the resonance optical depth ρtot. We plot the two-planet circular Hillstability limits (Petit et al. 2018) for both planet pairs in green and the predicted overlap limit for the three-planet MMRs (Eq. 2.7) in blue. Adapted from Petit et al. (2020). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography, TRAPPIST-1

Long-term Stability and Dynamical Spacing of Compact Planetary Systems

by Keith CowingDecember 29, 2024December 28, 2024

Exoplanet detection surveys revealed the existence of numerous multi-planetary systems packed close to their stability limit.

General illustration of the calibration of the distortion. The reference stars are used to adjust a bivariate polynom T that relates the positions of the detector plane to the sky positions. The motion of the target is observed using this transformation. -- astro-ph.IM

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Experimental Tests Of The Calibration of High Precision Differential Astrometry for Exoplanets

by Keith CowingDecember 29, 2024December 28, 2024

High precision differential Astrometry is the branch of astronomy that evaluates the relative position, distance and motion of celestial objects with respect to the stars present in the field of […]

A small planet orbiting its host star - Grok via Astrobiology.com

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report, Stellar Cartography

Methods To Characterise Exoplanet Host Stars From Spectroscopy

by Keith CowingDecember 28, 2024December 28, 2024

A key to understand exoplanets is characterisation of their host stars. One of the most powerful tools to characterise stellar properties like effective temperature, surface gravity and metallicity, is spectroscopy […]

Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Conferences and Meetings, Exoplanets, -moons, -comets, Habitable Zones, Space Weather & Heliophysics, Status Report, Stellar Cartography

Know Thy Star Know Thy Planet 2 Conference

by Keith CowingDecember 28, 2024December 28, 2024

This is a reminder that regular in-person registration for “Know Thy Star Know Thy Planet 2” closes Friday, January 17th. The conference dinner add-on closes Sunday, January 5th.

Spatial localization of the example superflare. (A) Kepler image of the same flare on KIC 8183083 as in Fig. 1 during the maximum flare light. (B) The same flare 30 min later. Greyscale (see color bar) indicates the flux in each pixel during the flare. The blue outlines indicate the four pixels used to extract the light curve (Fig. 1) and the cyan star is the catalog position of the star (25). The orange ellipses indicate the 68%, 95%, and 99.9% confidence levels obtained by fitting a model of a point source to those images. The star is located within the 99.9% confidence contour in both images, so we attribute the flare in the light curve to this target. -- astro-ph.SR

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Radiation, Space Weather & Heliophysics, Stellar Cartography

Sun-like Stars Produce Superflares Roughly Once Per Century

by Keith CowingDecember 22, 2024December 22, 2024

Stellar superflares are energetic outbursts of electromagnetic radiation, similar to solar flares but releasing more energy, up to 1036 erg on main sequence stars.

Artist's impression of a Sun-like star exhibiting a superflare as seen in visible light Credit MPS/Alexey Chizhik

Atmospheres, Climate, Weather, Biophysics, Habitable Zones, Press Release, Radiation, Space Weather & Heliophysics, Stellar Cartography

Sun-like Stars Produce Superflares Roughly One Per Century

by Keith CowingDecember 16, 2024December 16, 2024

There is no question that the Sun is a temperamental star, as alone this year’s unusually strong solar storms prove. Some of them led to remarkable auroras even at low […]

Stellar Cartography

From Stability to Instability: Characterizing the Eccentricities of Multi-planet Systems in the California Kepler Survey as a Means of Studying Stability

X-ray Activity Of Nearby G-, K-, And M-type Stars And Implications for Planet Habitability Around M stars

Identifying Flare Locations Through Exoplanet Transit Occultations

ALMA Observations of CO Isotopologues Towards Six Obscured post-AGB Stars

Long-term Stability and Dynamical Spacing of Compact Planetary Systems

Experimental Tests Of The Calibration of High Precision Differential Astrometry for Exoplanets

Methods To Characterise Exoplanet Host Stars From Spectroscopy

Know Thy Star Know Thy Planet 2 Conference

Sun-like Stars Produce Superflares Roughly Once Per Century

Sun-like Stars Produce Superflares Roughly One Per Century

Astrobiologist Dale Andersen’s Antarctic Field Report: Preview: Fall 2026 Lake Untersee Field Season

ALMA Reveals Planetary Formation Structures In Small Disks

Compatible Comma-Free Codes and the Origin of the Genetic Code

Simulations Of The Evolving Ozone Layer: Implications For The Early Earth, Exoplanets, And The Search For Life

VUV And mid-UV Photoabsorption Cross Sections Of Thin Films Of Glycine And Alanine: Application To Their Photochemistry In The Solar System