The sub-Neptune frontier has opened a new window into the rich diversity of planetary environments beyond the solar system. The possibility of hycean worlds, with planet-wide oceans and H2-rich atmospheres, significantly expands and accelerates the search for habitable environments elsewhere. Recent JWST transmission spectroscopy of the candidate hycean world K2-18 b in the near-infrared led to the

We report the confirmation of TOI-6324 b, an Earth-sized (1.059 ± 0.041 R⊕) ultra-short-period (USP) planet orbiting a nearby (∼20 pc) M dwarf. Using the newly commissioned Keck Planet Finder spectrograph, we have measured the mass of TOI-6324 b 1.17 ± 0.22 M⊕. Because of its extremely short orbit of just ∼6.7 hr, TOI-6324 b is intensely irradiated by its M dwarf host and is expected to be stripped

Quasiperiodic pulsations (QPPs) in the Balmer continuum of solar white-light flares (WLFs) are rarely reported, and accurately pinpointing the spatial source of flaring QPPs remains a significant challenge. We present spatiotemporal characteristics of QPPs of an X2.8 two-ribbon solar WLF (SOL2023-12-14T17:02), which was well observed by the White-light Solar Telescope (WST) on board the Advanced Space-based

Quasiperiodic eruptions (QPEs) are recurring soft X-ray transients emerging from the vicinity of supermassive black holes in nearby, low-mass galaxy nuclei; about 10 QPE hosts have been identified thus far. Here we report the NICER discovery of QPEs in the optically selected tidal disruption event (TDE) and extreme coronal line emitter (ECLE) AT2022upj, exhibiting a large spread in recurrence times

We present 2D numerical simulations of convection and waves in a 7M⊙ star across stellar ages ranging from zero age to terminal age main sequence. We show that waves efficiently transport angular momentum across the stellar radiative envelope at young ages. However, as the core recedes, leaving behind a “spike” in the Brunt–Väisälä frequency at the convective–radiative interface, the waves are severely

The James Webb Space Telescope has revealed low-luminosity active galactic nuclei at redshifts of z ≳ 4–7, many of which host accreting massive black holes (BHs) with BH-to-galaxy mass (MBH/M⋆) ratios exceeding the local values by more than an order of magnitude. The origin of these overmassive BHs remains unclear but requires potential contributions from heavy seeds and/or episodes of super-Eddington

Observations of massive, quiescent galaxies reveal a relatively uniform evolution: following prolific star formation in the early Universe, these galaxies quench and transition to their characteristic quiescent state in the local Universe. The debate on the relative role and frequency of the process(es) driving this evolution is robust. In this Letter, we identify 0.5 ≲ z ≲ 1.5 massive, quiescent galaxies

The ion-scale electromagnetic waves are observed frequently within 0.3 au. Their generation and dissipation driven by wave–particle interaction are very important energy transfer processes in the weak collision corona and solar wind and may be one of the important factors driving the evolution of ion velocity distribution functions therein. In this Letter, we statistically analyze the possible effects

The discovery of the kilonova (KN) AT 2017gfo, accompanying the gravitational wave event GW170817, provides crucial insight into the synthesis of heavy elements during binary neutron star (BNS) mergers. Following this landmark event, another KN was detected in association with the second-brightest gamma-ray burst (GRB) observed to date, GRB 230307A, and subsequently confirmed by observations of the

The brightest ever gamma-ray burst (GRB) 221009A displays a significant emission line component around 10 MeV. As the GRB central engine is neutron rich, we propose that the emission line could be originally due to the 2.223 MeV gamma rays following neutron capture with protons. The measured line profile can be adequately fitted with a neutron capture model that involves thermal broadening and a bulk

Determining stellar ages is challenging, particularly for cooler main-sequence (MS) stars. Magnetic evolution offers an observational alternative for age estimation via the age–chromospheric activity (AC) relation. We evaluate the impact of metallicity on this relation using near one-solar-mass stars across a wide metallicity range. We analyze a sample of 358 solar-type stars with precise spectroscopic

Galaxy chemical enrichment mechanisms have primarily been constrained by [α/Fe] and [Fe/H] measurements of individual stars and integrated light from stellar populations. However, such measurements are limited at higher redshifts (z > 1). Recently, we proposed an analogous diagram of the oxygen-to-argon abundance ratio, log(O/Ar), versus Ar abundance, 12+log(Ar/H), as a new diagnostic window for emission

Solar flares are frequently accompanied by coronal mass ejections (CMEs) that release a significant amount of energetic plasma into interplanetary space, potentially causing geomagnetic disturbances on Earth. However, many solar flares have no association with CMEs. The relationship between solar flare and CME occurrences remains unclear. Therefore, it is valuable to distinguish between active regions

We present aperture masking interferometry (AMI) observations of the star HIP 65426 at 3.8 μm, as part of the JWST Direct Imaging Early Release Science program, obtained using the Near Infrared Imager and Slitless Spectrograph instrument. This mode provides access to very small inner working angles (even separations slightly below the Michelson limit of 0.5λ/D for an interferometer), which are inaccessible

Recent results from Type Ia supernovae, baryon acoustic oscillations (BAOs), and the cosmic microwave background (CMB) indicate (1) potentially discrepant measurements of the matter density Ωm and Hubble constant H0 in the ΛCDM model when analyzed individually and (2) hint of dynamical dark energy in a w0waCDM model when data are combined in a joint analysis. We examine whether underlying dynamical

Variability is a fundamental signature for active galactic nuclei (AGN) activity and serves as an unbiased indicator for rapid instability happening near the center of supermassive black holes (SMBHs). Previous studies showed that AGN variability does not have strong redshift evolution, and scales with their bolometric luminosity and BH mass, making it a powerful probe to identify low-mass, low-luminosity

Fast radio bursts (FRBs) are a type of highly polarized, millisecond-duration electromagnetic pulse in the radio band, which is mostly produced at cosmological distances. These properties provide a natural laboratory for testing the extreme Faraday effect, a phenomenon in which two different propagation modes of a pulse separate after passing through a dense, highly ionized, and magnetized medium.

We study the impact of molecular (H2) and atomic (H i) hydrogen cooling on the galaxy formation threshold. We calculate the fraction of dark matter (DM) halos that exceeds a critical mass required for star formation, Mcrit(z), as a function of their peak mass. By convolving analytic halo mass accretion histories (MAHs) with models for Mcrit(z), we predict that halos with peak virial masses below ∼108M⊙

We report the discovery of two galaxy candidates at redshifts between 15.7 < z < 16.4 in James Webb Space Telescope (JWST) observations from the GLIMPSE survey. These robust sources were identified using a combination of Lyman break selection and photometric redshift estimates. The ultradeep NIRCam imaging from GLIMPSE, combined with the strong gravitational lensing of the AS1063 galaxy cluster, allows

The velocity dispersion–size relation (σv ∼ Rβ) is a crucial indicator of the dynamic properties of interstellar gas, where the slope is considered as β ∼ 0.5. Recent observations reveal a steep velocity dispersion–size relation with the slope β > 0.6, which cannot be explained by a single mechanism with only gravity (β ∼ 0.5) or shear (β ∼ 1). We present a two-component model to explain the steep

Recent observations have confirmed the direct association between tidal disruption events (TDEs) and quasiperiodic eruptions (QPEs). In addition, TDE hosts and QPE hosts are statistically found to be similar in their morphological properties and in the strong overrepresentation of poststarburst galaxies. Particularly, both of them show an intriguing preference for extending emission line regions, which

An analytic expression for the frequencies of standing waves in stars, applicable to any radial order n, is derived from ray-tracing equations by the mean of Wigner–Weyl calculus. A correction to previous formulas currently employed in asteroseismology is identified as the Berry phase, which accounts for the vectorial nature of wave propagation in stars. Accounting for this quantity significantly improves

The binary pulsar J0348+0432 was previously shown to have a mass of approximately 2 M⊙, based on the combination of radial-velocity and model-dependent mass parameters derived from high-resolution optical spectroscopy of its white-dwarf companion. We present follow-up timing observations that combine archival observations with data acquired by the Canadian Hydrogen Intensity Mapping Experiment (CHIME)

We conducted contemporaneous optical and near-infrared polarimetric and spectroscopic observations of C/2023 A3 (Tsuchinshan-ATLAS, hereafter T-A) from 2024 October 16 to December 17, covering a wide range of phase angles (20°–123°) and wavelengths (0.5–2.3 μm). We paid special attention to gas contamination in the dust polarization using these data. As a result, we find the maximum polarization degree

We present Atacama Large Millimeter/submillimeter Array observations of the [C I] 492 and 806 GHz fine-structure lines in 25 dusty star-forming galaxies (DSFGs) at z = 4.3 in the core of the SPT2349–56 protocluster. The protocluster galaxies exhibit a median ratio of 0.94, with an interquartile range of 0.81–1.24. These ratios are markedly different to those observed in DSFGs in the field (across a

It is widely recognized that adiabatic acceleration plays an essential role in the dynamics of the solar wind electron distribution. Nevertheless, the role of electron adiabatic cooling remains poorly understood, at least from an observational standpoint. Even the betatron cooling has never been verified in the solar wind. Here, we present a distinct event of simultaneous betatron cooling of halo and

Fast radio bursts (FRBs) are millisecond-duration radio transients from distant galaxies. While most FRBs are singular events, repeaters emit multiple bursts, with only two—FRB 121102 and FRB 180916B—showing periodic activity (160 and 16 days, respectively). FRB 20240209A, discovered by CHIME-FRB, is localized to the outskirts of a quiescent elliptical galaxy (z = 0.1384). We discovered a periodicity

Observations and models of transiting hot Jupiter exoplanets indicate that atmospheric circulation features may cause large spatial flux contrasts across their daysides. Previous studies have mapped these spatial flux variations through inversion of secondary eclipse data. Though eclipse mapping requires high signal-to-noise data, the first successful eclipse map—made for HD 189733b using 8 μm Spitzer

The production mechanism of fast radio bursts (FRBs)—mysterious, bright, millisecond-duration radio flashes from cosmological distances—remains unknown. Understanding potential correlations between burst occurrence times and various burst properties may offer important clues about their origins. Among these properties, the spectral peak frequency of an individual burst (the frequency at which its emission

Deuterium, a heavy isotope of hydrogen, is a key tracer of the formation of the solar system. Recent James Webb Space Telescope observations have expanded the data set of deuterium-to-hydrogen (D/H) ratios in methane on the KBOs Eris and Makemake, providing new insights into their origins. This study examines the elevated D/H ratios in methane on these KBOs in the context of protosolar nebula (PSN)

Radial migration is an important dynamical effect that has reshaped the Galactic disk, but its origin has yet to be elucidated. In this work, we present evidence that resonant dragging by the corotation of a decelerating bar could be the main driver of radial migration in the Milky Way disk. Using a test particle simulation, we demonstrate this scenario explains the two distinct age–metallicity sequences

Merging binary black holes (BBHs) formed dynamically in dense star clusters are expected to have uncorrelated spin–orbit orientations since they are assembled through many random interactions. However, measured effective spins in BBHs detected by LIGO/Virgo/KAGRA hint at additional physical processes that may introduce anisotropy. Here we address this question by exploring the impact of stellar collisions

We present high-angular-resolution (0 068, ∼400 pc) Atacama Large Millimeter/submillimeter Array (ALMA) imaging of the [C ii] line and dust continuum emission of PSO J352.4034–15.3373, a radio-loud quasar at z = 5.83. The observations reveal a remarkably close match between the orientation of the [C ii] and thermal dust emission mapped by ALMA and radio synchrotron emission of a radio jet previously

Spicules have often been proposed as substantial contributors toward the mass and energy balance of the solar corona. While their transition region (TR) counterpart has unequivocally been established over the past decade, the observations concerning the coronal contribution of spicules have often been contested. This is mainly attributed to the lack of adequate coordinated observations, their small

We present the multiwavelength study of the ejection of a plasma blob from the limb flare SOL2023-12-31T21:36:00 from NOAA 13536 observed by the Solar Ultraviolet Imaging Telescope (SUIT) on board Aditya-L1. We use SUIT observations along with those from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory and Spectrometer/Telescope for Imaging X-rays (STIX) on board Solar

We present the Cosmic Evolution Early Release Science (CEERS) Survey, a 77.2 hr Director’s Discretionary Early Release Science Program. CEERS demonstrates, tests, and validates efficient extragalactic surveys using coordinated, overlapping parallel observations with the JWST instrument suite, including NIRCam and MIRI imaging, NIRSpec low- (R ∼ 100) and medium- (R ∼ 1000) resolution spectroscopy, and

Nanophase iron (np-Fe) particles in space-weathered lunar regolith are widely concerning as they can change the spectral, chemical, and physical properties of lunar soils. These np-Fe particles were previously believed to be produced from lunar surface materials by space weathering processes, while the source of np-Fe particles from exotic micrometeorite (flux = ∼5 × 108 t/Ma) has been overlooked.

Lunar soil samples from young maria (formed <3.0 billion years ago (Ga)) preserve key records of recent space weathering history in the Earth–Moon system. China’s Chang’e-6 mission returned the first farside soil samples from a young mare (∼2.8 Ga) at the northeastern South Pole–Aitken basin. We present preliminary results on the space weathering properties of the Chang’e-6 soils. The glassy agglutinate

We investigated the alignment between the angular momenta of galaxy groups and the spines of their associated cosmic filaments. Our results demonstrate a significant tendency for these two orientations to be perpendicular, indicating that the rotation of a galaxy group does not originate from the spin of cosmic filaments. Instead, it is driven by the orbital angular momentum contributed by member galaxies

We present a new analytical model for the attenuation to Epoch of Reionization (EoR) galaxies by proximate neutral hydrogen gas. Many galaxy spectra in the EoR taken by JWST have shown a flux deficit at wavelengths just redward of the Lyman break, and this has been regarded as resulting from Lyα damping wing absorption by the increasing amount of neutral hydrogen in the line of sight. However, previous

The evolution of the velocity distribution of pickup ions is crucial for understanding the energetic neutral atom (ENA) fluxes observed by Interstellar Boundary Explorer. Pickup ions in the heliosheath contain two main components: those transmitted across the heliospheric termination shock and those locally created within the heliosheath. In this work, we discuss the velocity distribution of the latter

Understanding the ionizing photon escape from galaxies is essential for studying cosmic reionization. With a sample of 23 Lyman continuum (LyC) leakers (among which eight are high-confidence leakers) at 3 < z < 4.5 in the GOODS-S field, we investigate their morphologies using high-resolution data from the Hubble Space Telescope and the James Webb Space Telescope. We find that 20 of the 23 LyC leakers

Most black holes (BHs) formed in collapsing stars have low spin, though some are expected to acquire a magnetic accretion disk during the collapse. While such BH disks can launch magnetically driven winds, their physics and observational signatures have remained unexplored. We present global 3D general relativistic magnetohydrodynamic simulations of collapsing stars that form slowly spinning BHs with

Linkage between core-collapse supernovae and their progenitors is not fully understood and ongoing effort of searching and identifying the progenitors is needed. SN 2024abfl is a recent Type II supernova that exploded in the nearby star-bursting galaxy NGC 2146, which is also the host galaxy of SN 2018zd. From archival Hubble Space Telescope data, we have found a red source (mF814W ∼ 25) near the location

The merger of a black hole (BH) and a neutron star (NS) in most cases is expected to leave no material around the remnant BH; therefore, such events are often considered as sources of gravitational waves without electromagnetic counterparts. However, a bright counterpart can emerge if the NS is strongly magnetized, as its external magnetosphere can experience radiative shocks and magnetic reconnection

A systematic torque from anisotropic radiation can rapidly spin up irregular grains to the point of breakup. We apply the standard theory of rotational disruption from radiative torques to solar system grains, finding that grains with radii ∼0.03–3 μm at 1 au from the Sun are spun to the point of breakup on timescales ≲1 yr even when assuming them to have an unrealistically high tensile strength of

Tides play an important role in the circulation and mean state of the Earth’s oceans through inducing significant mixing. On other planets, tidal forcings could be highly amplified compared to Earth, such as planets orbiting relatively close to low-mass host stars, or planets having massive and/or close moons. The former scenario is especially important as, due to their abundance and their observational

The emerging population of long-period radio transients (LPTs) shows both similarities and differences with normal pulsars. A key difference is that their radio emission is too bright to be powered solely by rotational energy. Various models have been proposed (including both white dwarf or neutron star origins), and their nature remains uncertain. Known LPTs have minutes-to-hours-long spin periods

We present high-sensitivity and large-scale atomic hydrogen (H i) observations toward lenticular (S0) galaxy NGC 4111 using the Five-hundred-meter Aperture Spherical Radio Telescope. The column-density map shows that NGC 4111 and seven other different types of galaxies share a huge H i gas complex. The data also suggest that NGC 4111 is interacting with seven galaxies. Moreover, we identified a rotating

We introduce and apply a methodology based on dynamic time warping to compare the whole set of gamma-ray light curves reported in the Third Fermi-Large Area Telescope Pulsar Catalogue. Our method allows us to quantitatively measure the degree of global similarity between two light curves beyond comparing indicators such as how many peaks there are, what their separation is, and their width and height

Solar microflares are ubiquitous in the solar corona, yet their driving mechanisms remain a subject of ongoing debate. Using high-resolution coronal observations from the Solar Orbiter’s Extreme Ultraviolet Imager (EUI), we identified about a dozen distinct moving plasma structures (hereafter, “ tiny ejections”) originating from the centers of three homologous microflares out of four successive events

The nature of irregularly spaced pulses of rotating radio transients (RRATs) complicates interstellar scintillation studies. In this Letter, we report the primary scintillation parameters of a sample of RRATs using pairwise correlations of pulse spectra. Moreover, from the measured scintillation velocities, we constrain their transverse velocities. We also find a reduced modulation index, m = 0.13

Detections of fast X-ray transients (FXTs) have accrued over the last few decades. However, their origin has remained mysterious. Rapid progress is now being made thanks to timely discoveries and localizations with the Einstein Probe mission. Early results indicate that FXTs may frequently, but not always, be associated with gamma-ray bursts (GRBs). Here, we report on the multiwavelength counterpart

We present new astrometric constraints on the stochastic gravitational-wave background and construct the first astrometric Hellings–Downs curve using quasar proper motions. From quadrupolar vector spherical harmonic fits to the Gaia proper motions of 1,108,858 quasars, we obtain a frequency-integrated upper limit on the gravitational-wave energy density, (95% confidence limit), for frequencies between

The two-state solar wind paradigm is based on observations showing that slow and fast solar wind have distinct properties like helium abundances, kinetic signatures, elemental composition, and charge-state ratios. Nominally, the fast wind originates from solar sources that are continuously magnetically open to the heliosphere like coronal holes while the slow wind is from solar sources that are only

When a binary of early-type stars from the young stellar populations in the Galactic center (GC) region is scattered to the vicinity of the supermassive black hole (SMBH) Sgr A*, one of the components would be tidally ejected as an early-type hypervelocity star (HVS) and the counterpart would be captured on a tight orbit around Sgr A*. Dozens of B-type HVSs moving faster than the Galactic escape speed

Understanding the nature of compressible fluctuations in a broad range of turbulent plasmas, from the intracluster medium to the solar wind, has been an active field of research in the past decades. Theoretical frameworks for weakly compressible magnetohydrodynamical turbulence in an inhomogeneous background magnetic field predict a linear scaling of the normalized mass density fluctuation (δρ/ρ0)

Spectral energy distribution (SED) modeling is one of the main methods to estimate galaxy properties, such as photometric redshifts, z, and stellar masses, M*, for extragalactic imaging surveys. SEDs are currently modeled as light from a composite stellar population attenuated by a geometrically homogeneous foreground dust screen. This is despite evidence from simulations and observations that find

The Pleiades is a young open cluster that has not yet dynamically relaxed, making it an ideal target to observe various internal dynamical effects. By employing a well-defined sample of main-sequence (MS) cluster members, including both MS single stars and unresolved MS+MS binaries, we revisited their individual masses and mass functions and quantified the mass dependence of their radial distributions

The induced magnetosphere of Mars is highly dynamic, driven by both the upstream solar wind and the planet’s crustal magnetic fields. This variability can occur on timescales much shorter than a single spacecraft orbit, making it difficult to distinguish between spatial and temporal variations in the induced magnetosphere. In this study, we utilize simultaneous multipoint observations from the Mars