(astro-ph.EP Archives

Water line area maps expressed in units of µmˆ% of continuum. The four observation time windows are July 2011 at 67.09 µm, February 2012 at 66.44 and 67.09 µm, July-August 2012 at 66.44 and 67.09 µm, and January-February 2013 at 66.44 and 67.09 µm. Saturn’s 1-bar level is represented by the black ellipse, with the north pole facing upwards. A selection of iso-latitudes are plotted with grey lines. The rotation axis corresponds to the thin dashed black line. The beam spatial extent is illustrated by the circle in a dashed blue line. The black dots correspond to the central position of the spatial pixels. The position and extension of the beacon (see Table 3) at mid-observation time is represented with the thick dashed black lines. A cubic interpolation was applied to the data. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Enceladus, Icy Worlds, Imaging & Spectroscopy, Saturn, Status Report

Temporal Evolution Of Water Abundance In Saturn’s Hot Vortex Of 2011-2013

by Keith CowingMay 8, 2025May 8, 2025

Water vapour is delivered to Saturn’s stratosphere by Enceladus’ plumes and subsequent diffusion in the planet system. It is expected to condense into a haze in the middle stratosphere.

Planets emerge from the dense disk of gas and dust encircling young stars. -- NASA

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

Can Close-In Exoplanets Form By Pebble Accretion?

by Keith CowingMay 3, 2025

Pebble accretion is the leading theory for the formation of exoplanets more massive than the Earth.

CN measurement limits in the exocomet frame for a CN line width of 2.7, 10 and 20 km s−1. Contours show signal-to-noise upper limits. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Beta Pictoris, Comets and Asteroids, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report

Upper Limits On CN From Exocomets Transiting Beta Pictoris

by Keith CowingApril 22, 2025April 22, 2025

The young (23 Myr) nearby (19.4 pc) star β Pictoris hosts an edge-on debris disk with two gas giant exoplanets in orbit around it. Many transient absorption features have been […]

Visualisation of the hypothesis for the observed stripe features, with a reflection grating located at the E ring. A zoomed-in view is shown in the bottom right corner. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Enceladus, Icy Worlds, Imaging & Spectroscopy, Missions & Hardware, Saturn, Status Report

Peculiar Rainbows in Saturn’s E Ring: Uncovering Luminious Bands Near Enceladus

by Keith CowingMarch 9, 2025June 9, 2025

We report observations of stripe-like features in Enceladus’ plumes captured simultaneously by Cassini’s VIMS-IR and ISS NAC instruments during flyby E17, with similar patterns seen in VIMS-IR data from flyby […]

Spectral flux contributions over the range [1, 25] µm for a surface temperature of (Top) 250 K and (Bottom) 650 K. The white lines delineate the areas where the CFF per spectral band is higher than unity. The spectral range of LIFE and the vertical extent of the cloud are overplotted. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Impact Of Water Clouds On The Prospective Emission Spectrum Of Teegarden’s Star b As Observed By LIFE

by Keith CowingNovember 16, 2024November 16, 2024

Non-transiting terrestrial planets will be accessible by upcoming observatories of which LIFE is an example.

Sulfur distribution on the surface of Mercury expressed as S/Si (Nittler et al., 2020). The highest S abundances 90 degrees west at the equator and north of it coincides with the highest Ca and Mg abundances, referred to as the high magnesium region (HMR) (reproduced from Nittler et al., 2020). -- astro-ph.EP

Astrochemistry, Astrogeology, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mercury, Moon, Status Report

Sulfur In The Moon And Mercury

by Keith CowingOctober 29, 2024October 29, 2024

This chapter presents a comprehensive overview of the abundances and distribution of S, and the processes that control the behavior of S on the Earth’s Moon and on Mercury. The […]

Left panel: JWST/MIRI photometry eclipse depth measurement at 15 µm (black data point) in context with different atmospheric models (coloured full lines), and airless blackbody (BB) models for different Bond albedos (AB; brown dashed and dotted lines). Tday is the corresponding dayside brightness temperature as computed with Equation (2). All atmospheric scenarios are computed with AB = 0.1 and using the "f-approximation formula" based on Koll (2022). N2 and O2 are both spectrally inactive (no significant absorption features) at these wavelengths, thus yielding nearly identical thermal emission spectra. Only the N2/CO2 scenarios are plotted for simplicity. The result from the Eureka! reduction is also shown (orange data point). Right panel: Atmospheric models (coloured circles) and atmosphere-less models (squares) from the left panel averaged over the F1500W bandpass. The gray shaded region represents the lower and upper error on the photometric measurement (solid line) obtained through a simple mean of both pipeline results. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Hot Rocks Survey I: A Shallow Eclipse For LHS 1478 b

by Keith CowingOctober 18, 2024October 18, 2024

M dwarf systems offer a unique opportunity to study terrestrial exoplanetary atmospheres due to their smaller size and cooler temperatures. However, due to the extreme conditions these host stars impose, […]

The plume from Hunga Tonga-Hunga Ha‘apai behaved like a mega-thunderstorm that rose 58 kilometers (38 miles) into the atmosphere. NASA Earth Observatory images and video by Joshua Stevens, using data courtesy of Kristopher Bedka and Konstantin Khlopenkov/NASA Langley Research Center, and GOES-17 imagery courtesy of NOAA and the National Environmental Satellite, Data, and Information Service (NESDIS). Story by Sofie Bates, NASA’s Earth Science News Team, with Mike Carlowicz. Larger image

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Extinction events, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Impact events, Lava / magma ocean / Volcanic Worlds, Status Report, Terraforming & Geoengineering, Water/Hycean Worlds & Oceanography

X-Raying Neutral Density Disturbances in the Mesosphere and Lower Thermosphere induced by the 2022 Hunga-Tonga Volcano Eruption-Explosion

by Keith CowingOctober 16, 2024October 16, 2024

We present X-ray observations of the upper atmospheric density disturbance caused by the explosive eruption of the Hunga Tonga-Hunga Ha’apai (HTHH) volcano on 15 January 2022.

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.

TESS target pixel files for TOI-260 for sector 3 (left), and for TOI-286 for sector 1 ( right). The remaining sectors are shown in Appendix A. The target star is labelled as 1 and marked by a white cross in each case. All sources from the Gaia DR3 catalogue down to a magnitude contrast of 8 are shown as red circles, with the size proportional to the contrast. The SPOC pipeline aperture is overplotted in shaded red squares. -- astro-ph.EP

Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Three Super-Earths And A Possible Water World From TESS And ESPRESSO

by Keith CowingJune 12, 2024June 12, 2024

Since 2018, the ESPRESSO spectrograph at the VLT has been hunting for planets in the Southern skies via the RV method. One of its goals is to follow up candidate […]