Study Findings: The Influence of Passing Field Stars on the Solar System’s Dynamical Future

Posted on by onespaceman2000
Credit: Image by Yol Gezer from Pixabay.

Icarus abstract of the study findings:

The long-term dynamical future of the Sun’s planets has been simulated and statistically analyzed in great detail, but most prior work considers the solar system as completely isolated, neglecting the potential influence of field star passages. To understand the dynamical significance of field star encounters, we simulate several thousand realizations of the modern solar system in the presence of passing field stars for 5 Gyrs. We find that the impulse gradient of the strongest stellar encounter largely determines the net dynamical effect of field stars. Because the expected strength of such an encounter is uncertain by multiple orders of magnitude, the possible significance of field stars can be large. Our simulations indicate that isolated models of the solar system can underestimate the degree of our giant planets’ future secular orbital changes by over an order of magnitude. In addition, our planets and Pluto are significantly less stable than previously thought. Field stars transform Pluto from a completely stable object over 5 Gyrs to one with a ∼5% instability probability. Furthermore, field stars increase the odds of Mercury’s instability by ∼50%–80%. We also find a ∼0.3% chance that Mars will be lost through collision or ejection and a ∼0.2% probability that Earth will be involved in a planetary collision or ejected. Compared to previously studied instabilities in isolated solar systems models, those induced by field stars are much more likely to involve the loss of multiple planets. In addition, they typically happen sooner in our solar system’s future, making field star passages the most likely cause of instability for the next 4–4.5 Gyrs.

Citation: Kaib, Nathan A. and Raymond, Sean N., The influence of passing field stars on the solar system’s dynamical future, Icarus (2005).

https://doi.org/10.1016/j.icarus.2025.116632

Study-related stories:

The New York Times

Science News

Planetary Science Institute

Study Findings: No Certainty of a Milky Way–Andromeda Collision

Posted on by onespaceman2000
Image (Credit): The Andromeda galaxy, or M31, spans 260,000 light-years across. (NASA/JPL-Caltech)

Nature Astronomy abstract of the study findings:

It is commonly believed that our own Milky Way is on a collision course with the neighbouring Andromeda galaxy. As a result of their merger, predicted in around 5 billion years, the two large spiral galaxies that define the present Local Group would form a new elliptical galaxy. Here we consider the latest and most accurate observations by the Gaia and Hubble space telescopes, along with recent consensus mass estimates, to derive possible future scenarios and identify the main sources of uncertainty in the evolution of the Local Group over the next 10 billion years. We found that the next most massive Local Group member galaxies—namely, M33 and the Large Magellanic Cloud—distinctly and radically affect the Milky Way–Andromeda orbit. Although including M33 increases the merger probability, the orbit of the Large Magellanic Cloud runs perpendicular to the Milky Way–Andromeda orbit and makes their merger less probable. In the full system, we found that uncertainties in the present positions, motions and masses of all galaxies leave room for drastically different outcomes and a probability of close to 50% that there will be no Milky Way–Andromeda merger during the next 10 billion years. Based on the best available data, the fate of our Galaxy is still completely open.

Citation: Sawala, T., Delhomelle, J., Deason, A.J. et al. No certainty of a Milky Way–Andromeda collision. Nat Astron (2025).
https://doi.org/10.1038/s41550-025-02563-1

Study-related stories:

PBS

National Geographic

Daily Finland

Study Findings: Four Sub-Earth Planets Orbiting Barnard’s Star from MAROON-X and ESPRESSO

Posted on by onespaceman2000
Image (Credit): Conceptual art showing Barnard’s Star from the surface of one of its four orbiting planets. (Illustration by International Gemini Observatory/NOIRLab/NSF/AURA/R. Proctor/J. Pollard)

The Astrophysical Journal Letters abstract of the study findings:

Barnard’s Star is an old, single M dwarf star that comprises the second-closest extrasolar system. It has a long history of claimed planet detections from both radial velocities and astrometry. However, none of these claimed detections have so far withstood further scrutiny. Continuing this story, extreme precision radial velocity measurements from the ESPRESSO instrument have recently been used to identify four new sub-Earth-mass planet candidates around Barnard’s Star. We present here 112 radial velocities of Barnard’s Star from the MAROON-X instrument that were obtained independently to search for planets around this compelling object.

Citation: Ritvik Basant et al. Four sub-Earth planets orbiting Barnard’s Star from MAROON-X and ESPRESSO. ApJL 982 L1 (2025).
https://doi.org/10.3847/2041-8213/adb8d5

Study-related stories:

The University of Chicago

SciTechDaily

Astronomy Magazine

Study Findings: An Evaporite Sequence from Ancient Brine Recorded in Bennu Samples

Posted on by onespaceman2000
Image (Credit): Up close view of Asteroid Bennu. (NASA)

Nature abstract of the study findings:

Evaporation or freezing of water-rich fluids with dilute concentrations of dissolved salts can produce brines, as observed in closed basins on Earth and detected by remote sensing on icy bodies in the outer Solar System. The mineralogical evolution of these brines is well understood in regard to terrestrial environments, but poorly constrained for extraterrestrial systems owing to a lack of direct sampling. Here we report the occurrence of salt minerals in samples of the asteroid (101955) Bennu returned by the OSIRIS-REx mission. These include sodium-bearing phosphates and sodium-rich carbonates, sulfates, chlorides and fluorides formed during evaporation of a late-stage brine that existed early in the history of Bennu’s parent body. Discovery of diverse salts would not be possible without mission sample return and careful curation and storage, because these decompose with prolonged exposure to Earth’s atmosphere. Similar brines probably still occur in the interior of icy bodies Ceres and Enceladus, as indicated by spectra or measurement of sodium carbonate on the surface or in plumes.

Citation: McCoy, T.J., Russell, S.S., Zega, T.J. et al. An evaporite sequence from ancient brine recorded in Bennu samples. Nature 637, 1072–1077 (2025).
https://doi.org/10.1038/s41586-024-08495-6

Study-related stories:

Smithsonian Magazine

Sci.News

BBC

Study Findings: Detection of Carbon Dioxide and Hydrogen Peroxide on the Stratified Surface of Charon with JWST

Posted on by onespaceman2000
Image (Credit): Charon, Pluto’s largest moon, as captures by NASA’s New Horizons spacecraft. (NASA/JHUAPL/SwRI)

Nature Communications abstract of the study findings:

Charon, Pluto’s largest moon, has been extensively studied, with research focusing on its primitive composition and changes due to radiation and photolysis. However, spectral data have so far been limited to wavelengths below 2.5 μm, leaving key aspects unresolved. Here we present the detection of carbon dioxide (CO2) and hydrogen peroxide (H2O2) on the surface of Charon’s northern hemisphere, using JWST data. These detections add to the known chemical inventory that includes crystalline water ice, ammonia-bearing species, and tholin-like darkening constituents previously revealed by ground- and space-based observations. The H2O2 presence indicates active radiolytic/photolytic processing of the water ice-rich surface by solar ultraviolet and interplanetary medium Lyman-α photons, solar wind, and galactic cosmic rays. Through spectral modeling of the surface, we show that the CO2 is present in pure crystalline form and, possibly, in intimately mixed states on the surface. Endogenically sourced subsurface CO2 exposed on the surface is likely the primary source of this component, with possible contributions from irradiation of hydrocarbons mixed with water ice, interfacial radiolysis between carbon deposits and water ice, and the implantation of energetic carbon ions from the solar wind and solar energetic particles.

Citation: Protopapa, S., Raut, U., Wong, I. et al. Detection of carbon dioxide and hydrogen peroxide on the stratified surface of Charon with JWST. Nat Commun 15, 8247 (2024).
https://doi.org/10.1038/s41467-024-51826-4

Study-related stories:

Reuters

Science Alert

Futurism