The first eruption of the periodic nova T CrB for eighty years is anticipated soon, though with an unknown date. A refinement of the future eruption date is investigated. The investigation is based on the combination of the previous eruption dates and on the orbital ephemeris of the binary system, without any hypothesis on the eruption mechanism. It is predicted that the next eruption should appear around 2025 March 27 or November 10, or later.

In this Note, we discuss the rationale behind the IAU CPS's recommendation on satellite brightness for objects in low Earth orbit (LEO). Specifically, we clarify the reasoning behind the chosen altitude dependence and the limitations of this choice. We further discuss some approaches toward brightness limits for objects beyond LEO. This Note is intended for both astronomers and satellite operators in the spirit of furthering mutual cooperation.

Near-Earth objects (NEOs) that follow horseshoe paths, and approach our planet at close range and low relative velocity, may undergo mini-moon events in which their geocentric energy becomes negative for hours, days or months, but without completing one revolution around Earth while bound. An example of NEO experiencing such a temporarily captured flyby is 2022 NX₁, which was a short-lived mini-moon in 1981 and 2022. Here, we show that the recently discovered small body 2024 PT₅ follows a horseshoe path and it will become a mini-moon in 2024, from September 29 until November 25.

We highlight the announcement by the IAU Minor Planet Center of 128 new irregular moons of Saturn discovered in our CFHT imaging acquired in 2023. We were able to link 83 of the new moons to detections from our earlier 2019–2021 study. Of the 58 new retrograde moons with multiyear arcs, 46 are likely in the Mundilfari subgroup. This large fraction is in line with the steep size distribution of the subgroup and the idea that it was created by a recent collision. Also, by more than tripling the number of Kiviuq subgroup members, the new discoveries have confirmed that this subgroup is a very tightly grouped collisional family, although likely much older.

The total lunar eclipse on 2025 March 14 UT occurs nearly exactly 521 yr (one Hypersaros) after a similar eclipse on 1504 March 1 UT that is renowned for its importance to the voyage of Columbus to Jamaica. Eclipses separated by a Hypersaros have similar depths, appear very close to the same location in the sky, and occur at nearly the same time of year. This paper summarizes the results from a search for analogous cycles within the Five Millennium Catalogs of Lunar and Solar Eclipses. Under the two simple constraints of similar eclipse dates relative to the vernal equinox and similar paths of the Moon through the Earth's shadow, the most common time intervals between lunar eclipses separated by less than 1000 yr are the 521 yr Hypersaros and a 633 yr period of the Icosa-Inex-Triple-Saros. Notable cycles at longer periods occur at 1154, 1284, 1787, 1917, and 2308 yr.

The Porangaba meteorite fall was the result of a daylight fireball observed on 2015 January 9, in a large area of Sao Paulo, Brazil. It was considered a sporadic bolide not associated with any known meteor shower. Here, we show that the orbital properties of the recently discovered virtual impactor 2024 YR₄ (impact probability 0.021) are a possible match to those of the meteoroid responsible for the Porangaba meteorite fall with a probability of 0.050. Our data mining exploration also uncovered a group of seemingly related objects that includes virtual impactors 2017 UW₅, 2018 GG₄, 2019 SC, 2020 MQ₆₁, and 2020 DM₃.

The connection between Near-Earth asteroids and the main belt is well established, yet few concrete examples exist of asteroids that are migrating between the two regions. (355256) 2007 KN₄ presents a compelling case, as it may evolve first into a main belt asteroid, and then a potentially hazardous asteroid within a few tens of thousands of years. As it is approaching its best apparition in decades, observations of this asteroid are encouraged.

Tens of new moons around both Jupiter and Saturn have been announced on Minor Planet Electronic Circulars (MPECs) in late 2022 and early 2023. Jupiter now has 95 and Saturn 146 confirmed moons. Many smaller and fainter moons have also been detected at these planets but not yet confirmed through MPECs. These discoveries nearly complete the small moon population of Jupiter to about 2 km and Saturn to about 3 km and show new dynamical satellite families. The once lone Carpo is now joined by S/2018 J4, making it a group of two small prograde moons around Jupiter. The Inuit prograde family around Saturn appears to be 3 distinct groupings. S/2004 S24 seems to be a unique distant small Saturn prograde moon, as could be S/2006 S12 and S/2019 S6. S/2006 S20 might be the first found member of a compact Phoebe Saturn moon family.

Between Jupiter and Saturn about 1000 minor bodies exist in orbits with large eccentricities. Previously, this domain has been studied for asteroids with relatively small eccentricities indicating regions of stability with large escape times of up to several hundred million years. Orbits with large inclinations were particularly stable, even for massive planets. However, studies about retrograde orbits are sparse or missing. Here we investigate the stability behavior of massless bodies between Jupiter and Saturn ranging from perpendicular (i = 90^∘) to retrograde motion (i = 180^∘). Besides theoretical analyses of the solar system, our work may be of interest to future studies of exosolar planetary systems.

The solar magnetic field, thought to be generated by the motion of plasma within the Sun, alternates on the order of 11 yr cycles and is incompletely understood. Industries rely on accurate forecasts of solar activity, but can solar cycles be predicted? Of more than 100 predictions for cycle 25, most underestimated the amplitude (peak sunspot number). Fewer predictions were made for the timing of solar maximum, but timing predictions seem to be performing better than amplitude predictions. Reasons for inaccurate prediction are suggested, and perspectives are given on how future studies might improve upon the extant literature.

A photometric study of Comet 103P/Hartley 2 is presented, aiming at the detection and analysis of rotationally induced variability during its latest apparition 2023/2024. Brightness measurements within a 5000 km radius aperture using a green filtered spectral range reveal periodic variations, despite the use of different instrumentation, non-standard filters, and varying observing conditions. An increase of the rotation period from 18.6 to 19.1 hr within about 4 months was found, a slowing-down of the rotation similar to results from the apparition in 2010.

Reports of visual sightings of bands on Neptune made by E. S. Holden and J. M. Schaeberle at Lick Observatory are described. Holden's logbooks record that in 1888 September and October bands were discerned on the Neptunian disk and noted on seven nights. A summary of the logbook entries are given in this note, since they do not appear to have been previously published.

In this research note I update the associations between globular clusters and their putative galaxy progenitors determined in D. Massari et al., based on the kinematic measurements from the Gaia early data release 3 (eDR3). The table with the associations is available at https://www.oas.inaf.it/en/research/m2-en/carma-en/, and will be kept up-to-date whenever improved data become available. The same table will also provide updated age estimates from the CARMA project. Please cite this Note alongside Massari, Koppelman & Helmi 2019, eDR3 edition.

Recently, the KM3NeT Collaboration announced the detection of a 220 PeV neutrino from the celestial coordinates R.A. = 94$\mathop{.}\limits^{^\circ }$3 and decl. = −7$\mathop{.}\limits^{^\circ }$8 on 2023 February 13 at 01:16:47 UTC. The source for this extra-ordinary cosmic neutrino, designated KM3-230213A, is not identified yet but there has been speculation that it might be associated with a gamma-ray burst GRB 090401B. The purpose of this report is to search the association of this 220 PeV neutrino with potential GRB sources from a more general consideration of Lorentz invariance violation (LV) without predefined LV scale. We try to associate this extra-ordinary neutrino with potential GRBs within angular separation of 1°, 3° and 5° respectively and the results are listed in Table 1. We find the constraints E_LV ≤ 5.3 × 10¹⁸ GeV for subluminal LV violation and E_LV ≤ 5.6 × 10¹⁹ GeV for superluminal LV violation if KM3-230213A is a GRB neutrino.

We report the cometary activity of the Centaur 2023 RS₆₁ (RS61) evident in our UT 2025 January 2 observations with the Lowell Discovery Telescope, showing a coma and a ∼5$\mathop{.}\limits^{^{\prime\prime} }$9-long tail. The archival observations from the Pan-STARRS1 survey reveal two previously unnoticed activity episodes in 2017 and 2023, suggesting SR61 could be a rare outbursting Centaur similar to 174P/Echeclus. The outburst on UT 2017 October 10 at r_H = 13.5 au makes RS61 the second-most distant active Centaur after 95P/Chiron. We estimate a nucleus size between 4.7 km ≤ r_n ≤ 7.0 km, assuming typical Centaur geometric albedos, an upper-limit Afρ ≤ 245 cm and dust production rate $\dot{M}\,\leqslant \,131$ kg s⁻¹. As RS61 approaches the perihelion in 2028 its activity will likely increase, making this object an exciting observing target.