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Mastodon: AboutGet the appKeyboard shortcutsView source codev4.4.0-nightly.2025-04-01

#Astrodon

67 posts48 participants0 posts today
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Dr. Victoria Grinberg

Caroline #Herschel was an absolutely fascinating woman: stunted by a childhood encounter with typhus, she was actively stopped from learning more by her mother. Yet, she prevailed, becoming the first woman to get a salary as a scientist and the first woman to be employed by the government in England:

en.m.wikipedia.org/wiki/Caroli

The Royal Astronomical Society and the German Astronomical Society are jointly awarding the Caroline Herschel medal

ras.ac.uk/awards-and-grands/ca

Caroline Herschel portrait: (1750-1848) astronomer and sister of William Herschel
#astrodon#WomenInSTEM
Public
Andrea Luck

Ring Nebula as seen by JWST Space Telescope

Full size & more info: flic.kr/p/2qW1yL1
Credit: NASA/ESA/CSA/STScI/AndreaLuck CC BY

Target: Ring Nebula, NGC6720
Distance: 2,300 light-years
Date: 2022-08-04 / 2022-08-08
Instruments: NIRCam, MIRI
Filters: F770W, F560W, F335M, F300M, F212N, F162M
Colours Assigned: B/W, Red, Orange, Green, Cyan, Blue
PI: Michael Barlow
PI Institution: University College London
Proposal ID: 1558

A glowing, circular nebula with a bright, textured outer ring that fades into a dark background filled with stars. The center of the ring is a smooth, teal-blue area with faint, cloudy structures and small bright points. The ring itself appears reddish-orange with intricate filaments extending outward like wispy tendrils. Surrounding the nebula, the dark space is scattered with bright white stars, some with distinct diffraction spikes.
#JWST#Astronomy#Space
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REBOUND Citation Bot

A new paper by Merkulova et al. has cited REBOUND:
The impact of cometary outbursts on the orbits of comets in the Oort cloud ui.adsabs.harvard.edu/abs/2025 #nbody #astrodon

ADS · The impact of cometary outbursts on the orbits of comets in the Oort cloudThe surface layers of cometary nuclei are intensively irradiated by high energy protons, α-particles and heavy ions of galactic cosmic ray (GCR), leading to the formation of ions and radicals in the comet's matter. At low temperatures, high concentrations of radicals accumulated in the ice can be followed by a rapid release of energy during spontaneous or induced recombination. This process can provoke a gas release from the comet's surface layers. The resulting gas flux leads to a change in the velocity of comets, which affects the stability of their orbits. Repeated outbursts can occur over the comet's lifetime in the Oort cloud. This mechanism depends on the comet's size, the initial eccentricity, and the ejected mass during the outburst. We modeled the impact of repeated cometary outbursts on the orbits of comets in the Oort cloud. The results indicate that 49.5 % of comets with radii R<SUB>c</SUB> = 0.4 km and 72.4 % of comets with R<SUB>c</SUB> = 0.3 km and initial eccentricities e<SUB>c</SUB> ≥ 0.9 could leave the Oort cloud due to repeated outbursts. This fraction leaving comets for the initial eccentricities e<SUB>c</SUB> > 0 is 19.3 % for R<SUB>c</SUB> = 0.4 km and 54.1 % for R<SUB>c</SUB> = 0.3 km, respectively. The mechanism has the most effect on highly elongated orbits of comets.
Public
REBOUND Citation Bot

A new paper by Meier et al. has cited REBOUND:
On the origin of Jupiter's fuzzy core: constraints from N-body, impact and evolution simulations ui.adsabs.harvard.edu/abs/2025 #nbody #astrodon

ADS · On the origin of Jupiter's fuzzy core: constraints from N-body, impact and evolution simulationsIt has been suggested that Jupiter's fuzzy core could be a result of a giant impact. Here, we investigate the expected impact conditions from N-body simulations. We then use state-of-the-art SPH simulations to investigate the results of impacts with different conditions including various impactor masses and composition, different formation stages in Jupiter's growth, and different resolutions. We next simulate the long-term thermal evolution of Jupiter post-impact. We find that N-body simulations predict rather oblique impacts, and that head-on collisions are rare. Moreover, our results show that even under a head-on collision, Jupiter's fuzzy core cannot be formed. We next simulated Jupiter's thermal evolution and showed that unless post-impact temperatures are extremely low, a giant impact would not lead to an extended dilute core as inferred by interior models. We conclude that Jupiter's fuzzy core is not caused by an impact and is likely to be an outcome of its formation process.
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