The first exoplanet ever discovered in 1995 was what we now call a “hot Jupiter”, a planet as massive as Jupiter with an orbital period of just a few days. Today, hot Jupiters are thought to have formed far from their stars—similar to Jupiter in our Solar System—and later migrated inward. Two main mechanisms have been proposed for this migration: (1) high-eccentricity migration, in which a planet’s orbit is disturbed by the gravity of other celestial bodies and subsequently circularized by tidal forces near the star; and (2) disk migration, in which the planet moves gradually inward within the protoplanetary disk.

However, it is not straightforward to distinguish the mechanism a particular hot Jupiter experienced from observations alone. In the case of high-eccentricity migration, the gravitational perturbations can tilt the planet’s orbital axis relative to the star’s rotational axis, resulting in a measurable misalignment. However, tidal forces can realign these axes over time, meaning that an aligned orbit does not necessarily imply disk migration. As a result, there has long been no reliable observational method to identify planets that formed through disk migration.

To address this challenge, a research group led by PhD student Yugo Kawai and Assistant Professor Akihiko Fukui at the Graduate School of Arts and Sciences, the University of Tokyo, proposed a new observational method that takes advantage of the timescale of high-eccentricity migration itself.

Osaka Metropolitan University researchers enhanced Saccharomyces cerevisiae to increase its tolerance for high 2,3-butanediol concentrations. This was achieved by introducing mutations into the genomic DNA and successfully obtaining a mutant strain that proliferates 122 times more than the parent strain.

Tokyo, Japan – Scientists from Tokyo Metropolitan University have re-engineered the popular Lattice-Boltzmann Method (LBM) for simulating the flow of fluids and heat, making it lighter and more stable than the state-of-the-art. By formulating the algorithm with a few extra inputs, they successfully got around the need to store certain data, some of which span the millions of points over which a simulation is run. Their findings might overcome a key bottleneck in LBM: memory usage.

In statistics, data collection is a difficult process that demands thoughtful consideration. Securing a sufficient sample size can be challenging, or even impossible, regardless of the method employed. Small area estimation is a promising statistical technique that not only focuses on the target data but also incorporates data from related areas to improve mathematical accuracy. We spoke with Masayo Hirose, a researcher specializing in small area estimation, who shared the unique appeal of this field, the future direction of her work, and the message she hopes to convey to students.

Myelodysplastic syndrome (MDS) arises from defective blood stem cells that progressively lose their normal functions. Japanese researchers have revealed how changes in chromatin accessibility—how DNA is packaged—reprogram these stem cells toward faulty myeloid gene activity. This shift disrupts the balance of blood cell development and drives disease progression. The team also developed a chromatin-based “progenitor score” that accurately reflects disease severity and predicts patient prognosis in MDS.

Researchers at Tohoku University found the key to taming electrochemical reactions so they don’t produce rogue byproducts instead of valuable fuels.

A Japanese research team has successfully reproduced the human neural circuit in vitro using multi-region miniature organs known as assembloids, which are derived from induced pluripotent stem (iPS) cells. With this circuit, the team demonstrated that the thalamus plays a crucial role in shaping cell type-specific neural circuits of the cerebral cortex in humans. This discovery may pave the way for developing new medications to treat neurodevelopmental disorders.

Researchers at Osaka Metropolitan University have successfully cultured canine iPS cells in a medium without using components of human origin.

Neutron stars are compact objects with strong gravity and extreme magnetic fields. A research team investigated long-term X-ray variability in the neutron star NGC 7793 P13. This object is thought to be driven by supercritical accretion, where an extraordinary amount of gas falls onto the object and emits intense X-rays. The team found a mysterious relation between the X-ray luminosity and the rotation velocity. This result could provide clues to reveal the supercritical accretion mechanism.

Using a dual-cation substitution approach, researchers at Science Tokyo introduced ferromagnetism into bismuth ferrite, a well-known and promising multiferroic material for next-generation memory technologies. By replacing ions at both the bismuth and iron sites with calcium ions and heavier elements, they modified the spin structure and achieved ferromagnetism at room temperature. Additionally, negative thermal expansion was observed. This ability to engineer magnetism and thermal expansion in a multiferroic material aids in realizing future memory devices.