Gaia mission Archives

Hertzsprung–Russell diagram comparing the BGM-simulated stellar population (background) with the subset of Gaia sources (superimposed in red) for which reliable effective temperatures and absolute magnitudes are available. The Gaia sample is restricted to within 1 kpc due to parallax accuracy, and most white dwarfs lack reliable temperature estimates. Utilising the BGM enables consideration of the complete breadth of stellar types captured within the bycatch population, including bright Main Sequence stars and minimal confusion between faint Main Sequence and white dwarfs. -- astro-ph.IM

Astronomy & Telescopes, SETI & Technosignatures, Status Report

Simulating The Stellar Bycatch: Constraining The Prevalence Of Extraterrestrial Transmitters Within Radio SETI Surveys

by Keith CowingNovember 26, 2025November 26, 2025

Searches for radio technosignatures place constraints on the prevalence of extraterrestrial transmitters in our Galaxy and beyond. It is important to account for the complete stellar population captured within a […]

The host star properties in 𝑇SED − 𝑅★ space, along with their associated 68% confidence contours. For comparison we show a series of isochrones from Dotter et al. (2008) and the M-dwarf temperature radius relationship (red dashed line) derived in Morrell & Naylor (2019) and its bounds (blue shaded region). We emphasise that we do not expect all the stars to lie on these relationships, for example HD 97658 which is known to be metal poor (Howard et al. 2011) and so should lie below the Solar metallicity isochrones. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Using Stellar Spectral Energy Distributions to Measure Exoplanet Parameters

by Keith CowingNovember 13, 2025November 13, 2025

The ability to make accurate determinations of planetary parameters is inextricably linked to measuring physical parameters of the host star, in particular the stellar radius.

A possible Focal Plane dedicated instrument for HWO. Upper left panel: HWO telescope configuration for Exploratory Architecture Concepts) EAC1. Upper right panel : location of the focal plane and the detectur Calibration unit in the EAC1 case. Bottom left panel : location of the focal plane and the detector Calibration unit in the EAC3 case. Bottom right panel : possible focal plane concept with 4 GigaPyx 220M detectors and a central GigaPyx 14M detector. -- astro-ph.IM

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gaia Mission, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

Very High Precision Astrometry for Exoplanets and Dark Matter with the Habitable Worlds Observatory

by Keith CowingNovember 2, 2025November 2, 2025

Astrometry, one of the oldest branches of astronomy, has been revolutionized by missions like Hipparcos and especially Gaia, which mapped billions of stars with extraordinary precision.

(a) Normalized age distributions p(τ | [Fe/H]) for single stars, binned in [Fe/H] and smoothed using Gaussian filtering. Each vertical slice is normalized by its peak value. The blue line marks the peak age in each bin. Colored points show planet-hosting stars, classified by guiding-center radius Rg: inner (Rg < 7.2 kpc), local (7.2 ≤ Rg ≤ 9.2 kpc), and outer (Rg > 9.2 kpc). (b) Same as (a), but for [α/Fe] instead of [Fe/H]. -- astro-ph.SR

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

Insights Into Planet Formation From The Ages, Masses, and Elemental Abundances of Host Stars

by Keith CowingOctober 24, 2025October 22, 2025

How planetary systems form and evolve is a key question in astronomy. Revealing how host star properties, such as elemental abundances, age, and mass, differ from those of non-host stars, […]

Orbital characterization of TOI-402 B around A using multiple datasets.

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

Dynamical Architectures Of S-type Transiting Planets in Binaries II: A Dichotomy in Orbital Alignment of Small Planets in Close Binary Systems

by Keith CowingOctober 2, 2025October 2, 2025

Stellar multiplicity plays a crucial role in shaping planet formation and dynamical evolution. We present a survey of 54 TESS Objects of Interest (TOIs) within 300 pc that exhibit significant […]

Scientists have found thousands of exoplanets (planets outside our solar system) throughout the galaxy. Most can be studied only indirectly, but scientists know they vary widely, as depicted in this artist’s concept, from small, rocky worlds and gas giants to water-rich planets and those as hot as stars. Credit: NASA’s Goddard Space Flight Center Larger image

Astronomy & Telescopes, Exoplanets, -moons, -comets, Press Release

NASA’s Exoplanet Discovery Exceeds 6,000 Worlds

by Keith CowingSeptember 17, 2025September 17, 2025

The official number of exoplanets — planets outside our solar system — tracked by NASA has reached 6,000. Confirmed planets are added to the count on a rolling basis by […]

Sensitivity maps for the four CHEOPS visits of HD 95338. The first row represents the best-fit box depth (i.e. moon radius) in the ∆T0–W space. The 3σ lower limit of the moon radius is shown in the second row, while the third and fourth rows represent the ∆BIC and ∆AIC values between a solution with and without a moon. The empty (blank) areas are values that are below a threshold of 0 R⊕ for the moon radius (first 2 rows) and a threshold of 2 for the ∆BIC and ∆AIC (last 2 rows). The grey squares (and corresponding dotted lines) show the position of the transit of HD 95338b in this parameter space for each visit. An underlying linear trend is assumed for each of the four visits. -- astro-ph.EP

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

The CHEOPS View Of HD 95338b: Refined Transit Parameters, And A Search For Exomoons

by Keith CowingJuly 25, 2025July 25, 2025

Despite the ever-increasing number of known exoplanets, no uncontested detections have been made of their satellites, known as exomoons.

Today’s Picture of the Week tells a story of redemption for one lonely star. The young star MP Mus (PDS 66) was thought to be all alone in the Universe, surrounded by nothing but a featureless band of gas and dust called a protoplanetary disc. -- ESO

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gaia Mission, Status Report

MP Mus (PDS 66): You Can’t Judge A star By Its Protoplanetary Disc

by Keith CowingJuly 15, 2025July 14, 2025

In most cases, the material inside a protoplanetary disc condenses to form new planets around the star, leaving large gaps where the gas and dust used to be. These features […]

The Otautahi–Oxford model’s predicted asymptotic speed, radiant, and Galactic velocity distribution for ¯ q < 5 au ISOs, overplotted with the three known ISOs. The blue and orange lines on the radiant plot mark the Galactic and ecliptic planes respectively, and the yellow square marks the solar apex/local standard of rest (Sch¨onrich et al. 2010). -- astro-ph.EP

Astrochemistry, Astrogeology, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, Status Report

From A Different Star: 3I/ATLAS In The Context Of The Ōtautahi-Oxford Interstellar Object Population Model

by Keith CowingJuly 15, 2025July 14, 2025

The discovery of the third interstellar object (ISO), 3I/ATLAS (`3I’), provides a rare chance to directly observe a small body from another Solar System.

Average completeness (purple), number of planets before correction (red) and number of planets after correction (green) inside each bin (blue lines). Blue and orange circles represent cold Jupiters with and without inner super-Earth companions respectively. The contours on the left panel correspond to detection completeness of stars from the sample hosting at least one super-Earth. On the right panel, the contours correspond to detection completeness of stars that do not host super-Earths. Note that dividing the red number by the purple number gives an approximation of the green number. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Jupiter, Saturn, Status Report

Saturns, But Not Super-Jupiters, Occur More Frequently In The Presence Of Inner Super-Earths

by Keith CowingJune 27, 2025June 27, 2025

Studies from recent years have reached different conclusions regarding how frequently super-Earths are accompanied by long period giant planets and vice versa. This relation has been predicted to be mass […]

Gaia mission

Simulating The Stellar Bycatch: Constraining The Prevalence Of Extraterrestrial Transmitters Within Radio SETI Surveys

Using Stellar Spectral Energy Distributions to Measure Exoplanet Parameters

Very High Precision Astrometry for Exoplanets and Dark Matter with the Habitable Worlds Observatory

Insights Into Planet Formation From The Ages, Masses, and Elemental Abundances of Host Stars

Dynamical Architectures Of S-type Transiting Planets in Binaries II: A Dichotomy in Orbital Alignment of Small Planets in Close Binary Systems

NASA’s Exoplanet Discovery Exceeds 6,000 Worlds

The CHEOPS View Of HD 95338b: Refined Transit Parameters, And A Search For Exomoons

MP Mus (PDS 66): You Can’t Judge A star By Its Protoplanetary Disc

From A Different Star: 3I/ATLAS In The Context Of The Ōtautahi-Oxford Interstellar Object Population Model

Saturns, But Not Super-Jupiters, Occur More Frequently In The Presence Of Inner Super-Earths

Dinosaur-killing Asteroid Also Created A Dust Cloud That Insulated Earth, Charbroiling Cretaceous Creatures

Current Water Trapping Micro-habitats On The Surface Of Mars

Methanotrophy Under Extreme Alkalinity In A Serpentinizing System

ANDES, The High-resolution Spectrograph Oof The ELT: Simulated Performance Of The CORO Module And Overview Of The High-contrast Capabilities For Exoplanet Observations

When Polymers Meet Primitive Membranes: How Molecular Cooperation May Have Helped Life Begin