ESPRESSO Archives

Airmass variation and S/N of an ESPRESSO spectral order covering wavelengths from 567.76 nm to 576.42 nm, chosen as a midpoint in the selected Fe i spectral lines, as a function of the orbital phase of HD 189733 b. Blue points correspond to observations from 11 August 2021, and red points to those from 31 August 2021. The darker shaded region marks the phases where the planet is fully in transit, with lighter shading indicating the ingress and egress phases. -- astro-ph.SR

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

Exploring The Surface Of HD 189733 via Doppler Shadow Analysis Of Planetary Transits

by Keith CowingMarch 20, 2026March 20, 2026

Transmission spectroscopy has greatly advanced the study of exoplanet atmospheres, but stellar surface heterogeneities can contaminate transit spectra. Characterising how stellar spectra vary across the stellar disc is therefore essential […]

Combined fit results for K2-79 b. Transit fit to the light curve data from K2 long cadence (first row left), TESS long cadence (first row centre), and CHEOPS (first row right). The cadence (29.4 min for K2 long cadence, 120 s for TESS long cadence, and 60 s for CHEOPS) fluxes are plotted in grey, the fluxes binned every 30 min are over-plotted in black, and the fitted transit is shown by the red solid line. The RV fit to the HARPS-N & HIRES RVs is shown in the second row for K2-79 b. Coloured circular points show the phase folded RVs, grey points show these same values in subsequent phases, and the black line shows the best fit Keplerian model. The third row shows the RVs over the full ∼ 9 yr baseline, illustrating the absence of any significant long term trend. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Constraining Small Planet Compositions for Future Missions

by Keith CowingMarch 18, 2026March 18, 2026

Accurate mass and radius measurements of small transiting exoplanets are essential for probing their compositions, formation histories, and potential habitability.

Mass-radius diagram of small exoplanets (with radii ranging from 1–4 R⊕) with precise densities from the PlanetS catalog.

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

Densities Of Small Planets Around The M dwarfs TOI-4336 A And TOI-4342 With ESPRESSO: Three Sub-Neptunes, One Super-Earth, And A Neptune-mass Candidate

by Keith CowingFebruary 18, 2026February 18, 2026

We present the characterization of two planetary systems orbiting the M dwarfs TOI-4336 A (M3.5V) and TOI-4342 (M0V), each hosting two transiting planets previously validated with TESS and ground-based observations.

sBGLS periodograms of all planet candidates and the rotation period of the star. The apparent fringe pattern in all panels is caused by the sampling of the data in two chunks separated by approximately 13 y. -- astro-ph.EP

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

RedDots: Multiplanet System Around M Dwarf GJ 887 In The Solar Neighborhood

by Keith CowingFebruary 11, 2026February 11, 2026

GJ 877 is a bright M dwarf in the solar neighborhood with two currently reported nontransiting exoplanets with periods of 9 d and 21 d, along with an additional unconfirmed […]

Mass-radius diagram for TOI-283 b (red star) and known transiting planets with mass determinations with a precision better than 30 % (parameters taken from the TEPCat database; Southworth 2011). Planets orbiting K-type stars (4000 ≤ Teff ≤ 5300 K) are marked with orange circles. The lines in the mass-radius diagram represent the composition models of Zeng et al. (2016, 2019) for planets with pure iron cores (100 % Fe, brown line), Earth-like rocky compositions (32.5 % Fe plus 67.5 % MgSiO3, dashed green line), Earth-like compositions with a 0.1% H2 envelope (dotted purple line), and a water world with a 0.1 % H2 gas envelope (dash-dotted blue line). We show some Solar System planets for reference (Venus, Earth, Uranus, and Neptune). -- astro-ph.EP

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

TOI-283 b: A Transiting Mini-Neptune In A 17.6-day Orbit Discovered With TESS And ESPRESSO

by Keith CowingOctober 23, 2025October 22, 2025

Super-Earths and mini-Neptunes are missing from our Solar System, yet they appear to be the most abundant planetary types in our Galaxy.

Periodograms of the raw RV time series (top panel) as well as of the residuals after subtracting the OGP (middle panel) and the ILP (bottom panel), for HD 23079 (left), HD 196067 (center), and HD 86226 (right). -- astro-ph.EP

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

Architecture Of Planetary Systems With And Without Outer Giant Planets I. Inner planet Detections Around HD 23079, HD 196067, And HD 86226

by Keith CowingOctober 5, 2025

Understanding the link between outer giant planets (OGPs) and inner light planets (ILPs) is key to understanding planetary system formation and architecture.

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

The ATREIDES Program In Search Of Lost Exo-Neptunes

by Keith CowingSeptember 17, 2025September 17, 2025

An international team led by the University of Geneva (UNIGE), including scientists from the National Centre of Competence in Research PlanetS, the University of Warwick, and the Canary Islands Institute […]

An illustration of the adjusted telluric models for the solar and Titan spectra, where a 10% reduction from the best-fit model is applied to the solar spectrum and a 10% increase from the best-fit model is applied to the Titan spectrum, as described in Section 2.2. ‘o’ and ‘x’ markers indicate uncontaminated telluric lines used to estimate these adjustments. ‘o’ markers represent lines with expected strength, while ‘x’ markers denote lines with anomalous strength. The center of each ‘o’ or ‘x’ corresponds to the peak of the adjusted telluric model. The four regions shown were selected to clearly demonstrate both marker scenarios and to span a broad wavelength range relevant to the study. -- astro-ph.IM

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Status Report, Titan

Identification of Likely Methane Absorption Features in the Optical Spectra of Titan

by Keith CowingSeptember 9, 2025September 9, 2025

The optical spectra of Titan reveal a rich set of absorption features, most of which are likely associated with methane (CH4).

Mass-radius diagram of the well-characterized small planet population (Mp < 40M⊕,Rp < 4R⊕, mass error better than 25%, radius error better than 8%) from the PlanetS catalogue (Otegi et al. 2020; Parc et al. 2024) (semi-transparent circles), coloured by insolation. TOI-2322 b and c are shown as a pentagon and a hexagon respectively. The composition models of Zeng et al. (2019) are shown by the coloured curves. -- astro-ph.EP

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

TOI-2322: Two Transiting Rocky Planets Close To The Stellar Rotation Period And Its First Harmonic

by Keith CowingAugust 28, 2025August 28, 2025

Context. Active regions on the stellar surface can induce quasi-periodic radial velocity (RV) variations that can mimic planets and mask true planetary signals. These spurious signals can be problematic for […]

Artistic impression of the Proxima Centauri system, with the planets Proxima b and Proxima d, the latter confirmed by NIRPS. Credit: Gabriel Pérez Díaz (IAC)

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Proxima Centauri

The IAC Leads The First Scientific Results Of NIRPS, The New Infrared Exoplanet Hunter

by Keith CowingAugust 1, 2025August 1, 2025

The new infrared spectrograph NIRPS, built with the participation of the Instituto de Astrofísica de Canarias (IAC) and installed on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile, […]

ESPRESSO

Exploring The Surface Of HD 189733 via Doppler Shadow Analysis Of Planetary Transits

Constraining Small Planet Compositions for Future Missions

Densities Of Small Planets Around The M dwarfs TOI-4336 A And TOI-4342 With ESPRESSO: Three Sub-Neptunes, One Super-Earth, And A Neptune-mass Candidate

RedDots: Multiplanet System Around M Dwarf GJ 887 In The Solar Neighborhood

TOI-283 b: A Transiting Mini-Neptune In A 17.6-day Orbit Discovered With TESS And ESPRESSO

Architecture Of Planetary Systems With And Without Outer Giant Planets I. Inner planet Detections Around HD 23079, HD 196067, And HD 86226

The ATREIDES Program In Search Of Lost Exo-Neptunes

Identification of Likely Methane Absorption Features in the Optical Spectra of Titan

TOI-2322: Two Transiting Rocky Planets Close To The Stellar Rotation Period And Its First Harmonic

The IAC Leads The First Scientific Results Of NIRPS, The New Infrared Exoplanet Hunter

Sea Ice As An Origin Of Life Location For Hycean And Ocean Worlds

Viruses, Proviruses and Satellites from Asgard Archaea Enrichments Reveal Complex Microbial Interactions

Mars Rover Curiosity’s Hand Lens Imager (MAHLI) Calibration

Carbon and Sulfur Isotopes of Microfossils and Pyrites from Neoarchean Cherts: Microbial Diversity in an Ancient Deep-Marine Environment

Auroral Belts As Magnetically Localized Reactors For Prebiotic Chemistry On Early Earth