water snowline Archives

Infographic of the OPAL campaign simulations in the ambit of the Ariel mission Dry Run of 2025. The green box contains the codes presented in this paper that make up the Arχes and the Exoclimes suites. We use as inputs provided homogenised information for the stellar and planetary samples and we produce the elemental bulk composition and the molecular atmospheric composition of these planets. These are used to make highly detailed and realistic synthetic atmospheric spectra. -- astro-ph.EP

Ariel Mission, Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Missions & Hardware, Status Report, Stellar Cartography

The Origins Of Planets For ArieL (OPAL) Key Science Project: The End-to-end Planet Formation Campaign For The ESA Space Mission Ariel

by Keith CowingJanuary 26, 2026January 26, 2026

The growing body of atmospheric observations of exoplanets from space and ground-based facilities showcases how the great diversity of the planetary population is not limited to their physical properties but […]

ALMA Band 5 images of the HL Tau disk and the 321 GHz H2O line.

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release

Zooming Into The Water Snowline: High Resolution Water Observations of the HL Tau disk

by Keith CowingNovember 25, 2025November 25, 2025

Water is one of the central molecules for the formation and habitability of planets. In particular, the region where water freezes-out, the water snowline, could be a favorable location to […]

Derived CS rotational temperatures (top) and column densities (bottom) for our disk sample, sorted from left to right by column density. The median values are shown by the dashed orange lines and the shaded regions indicate the 16th-84th percentiles. Several points have uncertainties smaller than the markers. The values for the TW Hya and HD 163296 disks are taken from R. Teague et al. (2018) and C. J. Law et al. (2025), respectively. -- astro-ph.EP

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Habitable Zones, Interstellar, Press Release

A Submillimeter Survey Of CS Excitation In Protoplanetary Disks: Evidence Of X-ray-Driven Sulfur Chemistry

by Keith CowingNovember 16, 2025November 15, 2025

The sulfur chemistry in protoplanetary disks influences the properties of nascent planets, including potential habitability.

Disk temperature, vapor condensation timescale (tcond) and number density of water (nH2O) during the outburst dimming phase of the best-fit model. Here t' = t − tbeg is the time lapse since the bolometric luminosity started to decline. The value of Lbol corresponding to this time is labeled. In the top row, the range of 140-150 K is shaded in white to highlight the snowline region. At t' = 121 yr – the present epoch – the emission surfaces (τmm = 2/3) of ALMA band 5, 6 and 7 and disk photosphere (see Sect. C) are plotted along with the temperature contour. In the middle row, the region where no condensation occurs is plotted in white. In the bottom row, two lines denoting ice(vapor)-to-gas ratio of 10−3 are indicated to highlight the snowline region. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report

Dust And Water In V883 Ori: Relics Of A Retreating Snowline

by Keith CowingNovember 5, 2025November 5, 2025

V883 Ori is an FU-Orionis-type outburst system characterized by a shoulder at 50-70 au in its ALMA band 6 and 7 intensity profiles.

The 2-dimensional dust temperature distributions without viscous heating are shown for 10 L⊙ (top) and 100 L⊙ (bottom); Model E (left), Model E+D (middle), and Model PPD (right) are presented. The white solid line indicates the isothermal contour of Tdust = 100 K. The upper zoom-in panels of Model PPD show the water snowline inside the box of 20au×8au. -- astro-ph.SR

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Status Report

Water Snowline in Young Stellar Objects with Various Density Structures Using Radiative Transfer Models

by Keith CowingOctober 23, 2025October 22, 2025

Tracing the water snowline in low-mass young stellar objects (YSOs) is important because dust grain growth is promoted and the chemical composition varies at the water snowline, which influences planet […]

H2O photodissociation timescale and turbulent diffusion mixing timescale of the fiducial model using the chemical network. The 1, 10 and 100 year timescale contours are indicated in white in both panels. The dark blue contours in both panels indicates the 10−5 , 10−6 , and 10−8 H2O abundance contours of the fiducial chemistry model (see also top left panel of Fig. 1). The light blue line represents the H2O snow surface. -- astro-ph.EP

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

Understanding JWST Water Spectra: What Can Thermochemical Models Tell Us About The (Cold) Water In Protoplanetary Disks?

by Keith CowingSeptember 12, 2025September 12, 2025

Rotational H2O spectra as observed with JWST/MIRI provide a good probe of the temperature and column density structure of the inner disk. H2O emission can also be influenced by dynamical […]

Compilation of pebble mass flux vs. time evolutions. Solid lines show models developed in this study for various gap positions (see Sect. 3.1), which can be compared to mass fluxes required in pebble accretion simulations to form diverse inner planetary systems (dashed area, see M. Lambrechts et al. 2019) and the pebble mass flux inferred for the inner solar system using models capable of matching the NC/CC isotopic dichotomy (red dashed, see T. Lichtenberg et al. 2021). Symbols show ages and cold water masses of all 21 objects in our sample computed from JWST/MIRI line ratios (Table 1) in combination with Eq. 4 (see Appendix A), and the left and right y-axes are related through Eq. 3. Symbol color corresponds to inner gap position as obtained from high-spatial-resolution ALMA observations (see Sect. 2) and error-bars reflect uncertainties in measured line ratios. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Icy Worlds, Status Report

Cosmic Cascades: How Disk Substructure Regulates The Flow Of Water To Inner Planetary Systems

by Keith CowingAugust 15, 2025August 15, 2025

The influx of icy pebbles to the inner regions of protoplanetary disks constitutes a fundamental ingredient in most planet formation theories.

Global atmospheric C/O values for directly-imaged (blue) and transiting (purple) planets as a function of semi-major axis (left) and planet mass (right). This plot is reproduced using the data compiled in Hoch et al. (2023). Added to this plot are values from current C/O values reported in the literature (Ahrer et al. 2023; Alderson et al. 2023; Feinstein et al. 2023; Rustamkulov et al. 2023; Tsai et al. 2023; Edwards & Changeat 2024; Smith et al. 2024; Xue et al. 2024; Bell et al. 2023; Radica et al. 2023; Taylor et al. 2023; Coulombe et al. 2023) from the analysis (or inclusion) of data from JWST (orange). Error bars are included only if reported. The dotted horizontal line shows the solar C/O value (0.58; Asplund et al. 2021). -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Status Report

Linking Planet Formation To Exoplanet Characteristics: C/O As A Diagnostic Of Planet Formation

by Keith CowingAugust 14, 2025August 14, 2025

Gas-giant exoplanets are test cases for theories of planet formation as their atmospheres are proposed to carry signatures of their formation within the protoplanetary disk.

Water-equivalent content by weight in the Solar System and model predictions. Left upper panel: Midplane temperature of the disk using T1au = 145, 180, 200 and 300 K (from light blue to dark blue respectively) in Eq. 2. Left lower panel: The solid curves show the snowlines calculated using the Tinacci et al. (2023) BE distribution for the different temperature profiles (colours code as above). The data points show the median values of the water-equivalent content by weight for different objects of the Solar System (Sec. 3), where vertical bars represent the minimum and maximum range. Please note that the values reported in Tab. 1 are considered upper limits (see text). The uncertainty of the formation region of the various objects are shown as ellipses, distinguishing NC, CC, and comet populations. Right: Computed snowlines using T1au = 200 K in Eq. 2 and different models (see text): BE distribution (solid line), single BE (dashed) and condensation at 180 K (dotted). The right and left panels share the same vertical axis. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Habitable Zones, Interstellar, Status Report, Water/Hycean Worlds & Oceanography

Was Earth’s Water Acquired Locally During The Earliest Phases Of The Solar System Formation?

by Keith CowingJuly 8, 2025July 8, 2025

The origin of the terrestrial water remains debated, as standard Solar System formation models suggest that Earth formed from dry grains, inside the snowline of the Proto-Solar Nebula (PSN).

Distribution of known exoplanet masses plotted vs. semi-major axis (left) and semimajor axis normalized to the location of the snow-line (right) at asnow = 2.7AU M/MSun (green dashed line). Planets found by the Doppler/RV method (black lines with upward error bars indicating the sin i uncertainty, where i refers to line-of-sight inclination), transits (blue squares), microlensing (red error bar crosses), direct detection, (magenta triangles) timing (green triangles) and transit timing variations (gold diamonds). Small cyan spots indicate Kepler planets and planet candidates without mass measurements. Black letters show the locations of our Solar System's planets. Microlensing discoveries. -- astro-ph.EP

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

Exoplanet Detection With Microlensing

by Keith CowingMay 20, 2025May 20, 2025

Microlensing is the method of exoplanet detection that discovers solar system analog exoplanets.

water snowline

The Origins Of Planets For ArieL (OPAL) Key Science Project: The End-to-end Planet Formation Campaign For The ESA Space Mission Ariel

Zooming Into The Water Snowline: High Resolution Water Observations of the HL Tau disk

A Submillimeter Survey Of CS Excitation In Protoplanetary Disks: Evidence Of X-ray-Driven Sulfur Chemistry

Dust And Water In V883 Ori: Relics Of A Retreating Snowline

Water Snowline in Young Stellar Objects with Various Density Structures Using Radiative Transfer Models

Understanding JWST Water Spectra: What Can Thermochemical Models Tell Us About The (Cold) Water In Protoplanetary Disks?

Cosmic Cascades: How Disk Substructure Regulates The Flow Of Water To Inner Planetary Systems

Linking Planet Formation To Exoplanet Characteristics: C/O As A Diagnostic Of Planet Formation

Was Earth’s Water Acquired Locally During The Earliest Phases Of The Solar System Formation?

Exoplanet Detection With Microlensing

Mars Exploration Program Analysis Group (MEPAG) Concerns

Bridging Astrobiology Research and Education Through Interactive Learning Frameworks

Viking In The History And Future Of Astrobiology Programs

Collaborating With Artists In The Search For Life

Dual Use Technology – An Astrochemistry Spin Off