Stellar Cartography Archives

Artist concept of the gas giant planet WD1856b orbiting a white dwarf star. The planet is 7 times larger than the Earth-sized white dwarf it orbits. WD1856b has methane and hazes in its atmosphere, which would give it a similar colour to Saturn's moon Titan. The white dwarf formed from a star that died 5 billion years ago and has been cooling ever since, giving it an orange colour similar to the sun. Credit NASA, ESA, CSA, Ralf Crawford (STScI)

How A Giant Planet Survived Its Star’s Death

by Keith CowingJuly 4, 2026July 4, 2026

[Northwestern University] When astronomers discovered a giant planet orbiting a dead star in 2020, they wondered how it survived its star’s violent demise. Now, observations from NASA’s James Webb Space […]

Sketch of the dust grain growth and disk structure. The physical processes, observational tech- niques, and disk components depicted are described in Sect. 1. The horizontal axis in the upper panel repre- sents increasing particle size (and implicitly evolutionary time), from micron-sized grains to planetary cores. The disk in the sketch coarsely extends to 30–100 au. The inner part highlights the motion of the ionized gas at (sub-)au scale toward the star following the magnetic field. -- astro-ph.EP

Exoplanets, -moons, -comets

Demographics Of Planet-forming Disks With The SKAO

by Keith CowingJuly 3, 2026July 3, 2026

[astro-ph.EP] Understanding how solid material in planet-forming disks evolves from micron-sized dust to planetary cores is a central challenge in modern astrophysics. This study has advanced dramatically in the past […]

ESO/L. Calçada/P. Delorme/Nick Risinger (skysurvey.org)/R. Saito/VVV Consortium via NASA Larger image

Exoplanets, -moons, -comets

Free Floating Exoplanets or Merely Detached?

by Keith CowingJuly 1, 2026July 1, 2026

[Astrophysical Journal] Microlensing surveys suggest the presence of a surprisingly large population of free-floating planets, with a rate of about two Neptunes per star.

The Cosmic Shoreline. Light-green dots are all known exoplanets with reported atmospheric detections from the ExoAtmospheres database, noting that some of these detections are tentative or remain contested in the literature (e.g., GJ 1132 b). Solar System objects are marked as black crosses or green triangles if they host an atmosphere. The red dashed line is the cosmic shoreline as defined by Zahnle & Catling (2017). The black dotted is the same classical line, preserving the slope, but taking as zero point the exoplanet 55 Cnc e. The black dashed-dotted line is our newly proposed Empirical Exoplanet Cosmic Shoreline (EECS), which makes use of both Mars and several exoplanet atmospheric detections to define the slope and zero-point value. The numbers highlighted in the inset show the names of the seven planets discussed in the definition of the EECS. -- astro-ph.EP

Uncategorized

An Empirical Determination Of The Cosmic Shoreline

by Keith CowingJune 23, 2026June 23, 2026

The cosmic shoreline concept was introduced to separate planets with atmospheres from those without, by relating the cumulative X-ray and extreme-ultraviolet (XUV) instellation (integrated over the planet’s lifetime) to the […]

Radii and eccentricities of the comparison NEA sample. (A to C) Same as Fig. 1 but for the comparison sample of individual eccentricity measurements reported in the NEA database (27). All data points are individual measurements and have not been binned. Error bars indicate the 1 𝜎 uncertainties from previous studies as reported in the NEA database. -- astro-ph.EP

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

Super-Earths And Mini-Neptunes Follow Different Orbital Period-eccentricity Relations

by Keith CowingJune 19, 2026June 19, 2026

Many exoplanets have been observed with radius sizes between that of Earth and that of Neptune and are thus classified into two groups: super-earths (SEs) and mini-neptunes (MNs).

Artist’s impression of the CHEOPS space telescope. © ESA / ATG medialab

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Missions & Hardware, Press Release, Stellar Cartography

CHEOPS Exoplanet Mission Extended

by Keith CowingJune 16, 2026June 16, 2026

Following the remarkable scientific achievements of the space telescope CHEOPS, the European Space Agency (ESA) has decided to extend the mission once again.

Exoplanet 29 Cygni b, seen in this artist’s concept, is a gas giant weighing about 15 times the mass of Jupiter. It orbits a type A star (shown at upper right) slightly hotter and more massive than our Sun, at an average distance of 1.5 billion miles. The star is known to possess a dusty debris disk. A hypothetical comet fragment is shown approaching the planet, while previous impacts have left dark splotches on its cloudtops, similar to what was seen from the Shoemaker-Levy 9 impact on Jupiter in our solar system. -- NASA Larger image

Astrogeology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release, Stellar Cartography

Webb Redefines The Dividing Line Between Planets And Stars

by Keith CowingJune 16, 2026June 16, 2026

Planets, like those in our solar system, form in a bottom-up process where small bits of rock and ice clump together and grow larger over time. But the heftier the […]

The distribution of planetary radius and orbital period of TOIs and new false positives and planet candidates. COUNTESS discovered 38 new planetary signals, with 28 of them being FPs through triceratops validation and LEOVetter pixel-vetting. Note that the square symbols indicate TOI FPs that were successfully recovered as FPs through COUNTESS. -- astro-ph.EP

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

COUNTESS I: A Uniformly Vetted Catalog of Known and New Transiting Exoplanets in the TESS Northern Continuous Viewing Zone

by Keith CowingJune 15, 2026June 15, 2026

The Transiting Exoplanet Survey Satellite (TESS) has transformed the study of nearby exoplanetary systems; however, its nominal observing strategy limits sensitivity to planets with orbital periods shorter than ∼10 days […]

Super-Earths and sub-Neptunes are fairly common across our galaxy, but they don’t appear in our own solar system. Their size ranges fall in between Earth and Neptune. Credit: Keith Miller (Caltech/IPAC/SELab)

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Stellar Cartography

Finding Patterns in Planets: Researchers Explore the Demographics of Alien Worlds in K2 Data

by Keith CowingJune 11, 2026June 11, 2026

Our galaxy is jam-packed with planets, with thousands already discovered and millions more expected to eventually come into view. Within this ever-growing bounty, surprises have abounded, revealing that our solar […]