sub-Earth Archives

Barnard's Star

The Barnard’s Star Planetary System: Stability, Composition, and Evolution of Four Sub-Earth Exoplanets

by Keith CowingJune 24, 2026June 24, 2026

Barnard’s Star is the nearest single star to the Sun (1.8 pc), and hosts four recently-discovered planets.

Radial Velocity (RV) variation of GJ 367 observed with Left: ESPRESSO (black diamonds) and Right: ESPRESSO + HARPS (grey circles). For both left and right plots, panel a) shows the time-seies RV measurements. The best-fit radvel Gaussian Process (GP) single-Keplerian model for the ESPRESSO + HARPS combined dataset (grey line) used to remove stellar and instrumental correlated noise (see Sec. 4) is shown in the right hand side. The best-fit Keplerian orbital solution (blue line) is shown in each side. Panel b) shows the fit residuals (data - model). Panel c) shows the RV variations of GJ 367 as a function of orbital phase. The red points represent RVs binned to 10% of Porb. -- astro-ph.EP

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

Revisiting The Exo-Mercury Candidate GJ 367 b With ESPRESSO And A Self-Consistent Tidal Distortion Model

by Keith CowingJune 22, 2026June 21, 2026

We report revised mass and radius measurements for GJ 367 b, an ultra-short-period (7.7 hr) sub-Earth in a multi-planet system orbiting a nearby (~9 pc) M dwarf host. Previous mass […]

Phase-folded TESS light curve utilizing all 54 available sectors, binned to 5 minutes (blue points with error bars). The clear U-shape morphology and shallow depth (∼ 158 ppm) are consistent with a transiting planet. Note that the absence of secondary eclipses is further analyzed in Figure 3. -- astro-ph.EP

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

Physical Vetting of the Ultra-Short-Period Sub-Earth TOI 864.01

by Keith CowingJanuary 9, 2026January 9, 2026

We present a comprehensive analysis of TOI 864.01, a transit-like signal associated with the M-dwarf TIC 231728511.

ESPRESSO RV measurements (right) and GLS periodograms (left) of GJ 699 after subtracting the median of each dataset before (E18) and after (E19) the intervention in June 2019. Also shown are RV measurements from the ESPRESSO Data Reduction Software (DRS; top), from the S-BART template matching (TM) code (middle), and from the line-by-line LBL code (bottom).-- astro-ph.EP

Alpha Centauri, Astronomy & Telescopes, Barnard's Star, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

A Sub-Earth-mass Planet Orbiting Barnard’s Star

by Keith CowingOctober 4, 2024

Barnard’s star is a primary target within the ESPRESSO guaranteed time observations (GTO) as it is the second closest neighbour to our Sun after the α Centauri stellar system.

This artist’s impression shows Barnard b, a sub-Earth-mass planet that was discovered orbiting Barnard’s star. Its signal was detected with the ESPRESSO instrument on ESO’s Very Large Telescope (VLT), and astronomers were able to confirm it with data from other instruments. An earlier promising detection in 2018 around the same star could not be confirmed by these data. On this newly discovered exoplanet, which has at least half the mass of Venus but is too hot to support liquid water, a year lasts just over three Earth days.Credit:ESO/M. Kornmesser

Astronomy & Telescopes, Barnard's Star, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release

A Sub-Earth Mass Planet Has Been Discovered Orbiting Barnard’s Star

by Keith CowingOctober 1, 2024October 1, 2024

Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered an exoplanet orbiting Barnard’s star, the closest single star to our Sun. On this newly discovered exoplanet, […]

The ratio of a planet’s surface escape velocity squared v2 esc to its orbital velocity squared v2 K as a function of planet’s orbital distance and mass (equation 12). For v 2 esc/v2 K > 1, ejections are more likely than mergers, which we expect towards large orbital distances where the gravitational potential of the central star is shallower and for larger planet mass which can impart greater kinetic energy through scattering. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Status Report

Planet Mass Function Around M Stars At 1-10 au: A Plethora Of Sub-Earth Mass Objects

by Keith CowingOctober 1, 2024October 1, 2024

Small planets (≲1 M⊕) at intermediate orbital distances (∼1 au) represent an uncharted territory in exoplanetary science. The upcoming microlensing survey by the Nancy Grace Roman Space Telescope will be […]

Planet radius with radius uncertainties verses orbital period for planets in systems of more than 3-planets. We use the data from Lissauer et al. (2023) and limit the study to FGK stars. The radius gap is visible near 2 R⊕ with a slope which depends on orbital period. Planets with periods over 1000 days are excluded from the gap complexity (C) analysis. Additionally, planets with a radius over 6 R⊕ or radius uncertainties over 50% are used in the C calculation but excluded from the radius distribution analysis. -- astro-ph.EP

Exoplanets, -moons, -comets, Status Report, Stellar Cartography

The Distribution of Planet Radius in Kepler Multiplanet Systems Depends on Gap Complexity

by Keith CowingJune 19, 2024

The distribution of small planet radius (<4 R⊕) is an indicator of the underlying processes governing planet formation and evolution. We investigate the correlation between the radius distribution of exoplanets […]

The light curves and best fit models resulting from the Eureka! pipeline. The columns show, from left to right: transit 1, transit 2, transit 3. The rows show, from top to bottom: 1) the white light curve and residuals, 2) the spectroscopic light curves, 3) the best-fit models to the spectroscopic light curves, 4) the residuals from the spectroscopic light curve fitting. -- astro-ph.EP

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

JWST/NIRCam Transmission Spectroscopy Of The Nearby Sub-Earth GJ 341b

by Keith CowingJanuary 12, 2024January 12, 2024

We present a JWST/NIRCam transmission spectrum from 3.9−5.0 μm of the recently-validated sub-Earth GJ 341b (RP=0.92 R⊕, Teq=540 K) orbiting a nearby bright M1 star (d=10.4 pc, Kmag=5.6).

Kepler-1409b, as listed in the Kepler catalog, orbits its host star KID 12405333 with a period of 0.76486 days. This transit period has been precisely detected by the GPFC method. In the top panel, a clear transit signal is visible in the folded light curve at this identified period of p=0.76486 days. Meanwhile, the bottom panel reveals a peak CNN score of 0.99999964 at the same period, along with another notable score of 0.995469 at its harmonic half-period of p=0.38243. -- astro-ph.EP

AI - Data - Apps - Cybernetics, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Discovery of Small Ultra-short-period Planets Orbiting KG Dwarfs in Kepler Survey Using GPU Phase Folding and Deep Learning Detection System

by Keith CowingJanuary 2, 2024January 2, 2024

Since the discovery of the first hot Jupiter orbiting a solar-type star, 51 Peg, in 1995, more than 4000 exoplanets have been identified using various observational techniques.

HARPS RV time series of GJ 367 along with the best-fitting five-signal model (three planets + stellar rotation + long-period stellar signal). Data are shown as blue filled circles with their nominal uncertainties. The vertical gray lines mark the error bars including the RV jitter. -- astro-ph.EP)

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

Company for the ultra-high density, ultra-short period sub-Earth GJ 367 b: discovery of two additional low-mass planets at 11.5 and 34 days

by Keith CowingJuly 19, 2023July 19, 2023

GJ 367 is a bright (V ≈ 10.2) M1 V star that has been recently found to host a transiting ultra-short period sub-Earth on a 7.7 hr orbit. With the […]

sub-Earth

The Barnard’s Star Planetary System: Stability, Composition, and Evolution of Four Sub-Earth Exoplanets

Revisiting The Exo-Mercury Candidate GJ 367 b With ESPRESSO And A Self-Consistent Tidal Distortion Model

Physical Vetting of the Ultra-Short-Period Sub-Earth TOI 864.01

A Sub-Earth-mass Planet Orbiting Barnard’s Star

A Sub-Earth Mass Planet Has Been Discovered Orbiting Barnard’s Star

Planet Mass Function Around M Stars At 1-10 au: A Plethora Of Sub-Earth Mass Objects

The Distribution of Planet Radius in Kepler Multiplanet Systems Depends on Gap Complexity

JWST/NIRCam Transmission Spectroscopy Of The Nearby Sub-Earth GJ 341b

Discovery of Small Ultra-short-period Planets Orbiting KG Dwarfs in Kepler Survey Using GPU Phase Folding and Deep Learning Detection System

Company for the ultra-high density, ultra-short period sub-Earth GJ 367 b: discovery of two additional low-mass planets at 11.5 and 34 days

Ocean World Genomics: Earth’s Deep Sea Is An Untapped Evolutionary Engine

Project Hephaistos — IV. James Webb Space Telescope Observations of Two Dyson Sphere Candidates

Offworld Away Team Training: Cave Surveys

How Early RNA-based Life May Have Repaired Its Genome

Effect Of Ice Charging On The Astrochemistry Of Interstellar Sulfur Bearing Species On Amorphous Solid Water