Annual Review of Astronomy and Astrophysics最新文献

{"title":"Chemistry of Dark Molecular Clouds","authors":"Yuri Aikawa, Izaskun Jiménez-Serra, Paola Caselli","doi":"10.1146/annurev-astro-051024-031607","DOIUrl":"https://doi.org/10.1146/annurev-astro-051024-031607","url":null,"abstract":"Recent molecular line surveys, particularly toward the starless core TMC-1 CP (Taurus molecular cloud–1 cyanopolyyne peak), have greatly expanded the inventory of interstellar molecules, revealing numerous isomers and even aromatic species. Their diverse formation pathways—from ion–molecule reactions to the possible fragmentation of carbonaceous grains—remain under debate, linking chemistry to the life cycle of the interstellar medium. Simple tracers such as carbon chains and deuterated ions are used to probe the physical conditions and evolutionary state of nearby filaments and cores, as well as in massive infrared dark clouds. Ice chemistry has also entered a new era with the <jats:italic>James Webb Space Telescope</jats:italic> : Spatial distributions of ices indicate a connection between catastrophic freezeout, established in the prestellar core L1544, and formation of complex organic molecules. Overall, TMC-1 CP and L1544 are not outliers but representative laboratories of molecular cloud physics and chemistry. Extending these findings across diverse environments, from the Central Molecular Zone to low-metallicity galaxies, is essential for a unified picture of how interstellar chemistry regulates the path from clouds to stars and planets.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"125 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theory, Simulations, and Observations of Stellar Mergers","authors":"Fabian R.N. Schneider","doi":"10.1146/annurev-astro-051024-050338","DOIUrl":"https://doi.org/10.1146/annurev-astro-051024-050338","url":null,"abstract":"Stellar mergers are responsible for a great variety of astrophysical phenomena. They form blue straggler stars, give rise to spectacular transients, and produce some of the most massive stars in the Universe. Here, we focus on mergers from binary evolution and stellar collisions but do not cover mergers involving compact objects. We review how mergers come about, explain the physics and outcomes of the merger process, discuss the evolution and ultimate fates of merged stars, and relate to observations. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Mergers of main sequence stars often fully rejuvenate and have interior structures similar to genuine single stars. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Contrarily, mergers involving post–main sequence stars can have interior structures that cannot be achieved by single-star evolution. Some of these merger products may become long-lived blue supergiants and even end their evolution as such stars. They could thus explode in SN 1987A-like events, lead to interacting and superluminous supernovae, or collapse into very massive black holes. Such black holes may even populate the pair-instability-supernova black-hole mass gap. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Strong magnetic fields are produced in stellar mergers. Merged stars may thus be at the origin of some magnetic OBA stars and their descendants, highly magnetic white dwarfs and neutron stars. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Initially, stellar merger products rotate rapidly, but there are several mechanisms that can quickly spin them down. Hence, merged stars may be rather slow rotators for most of their evolution. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"458 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithium as a Probe of Stellar and Galactic Physics","authors":"Corinne Charbonnel, Nikos Prantzos","doi":"10.1146/annurev-astro-051024-023342","DOIUrl":"https://doi.org/10.1146/annurev-astro-051024-023342","url":null,"abstract":"Lithium plays a unique role in astrophysics, as it is a powerful diagnostic for the physics and evolution of low-mass stars, Galactic archaeology, and cosmology. We review the Li observations in stars at different phases of their evolution, the strengths and the limitations of the current theoretical stellar models to explain the Li abundance data, and our understanding of the Li sources and of the evolution of Li throughout the Galactic history. Key takeaways from the current state of the research in the field include the following: <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Stellar evolution models accounting for fundamental transport processes of chemical species and angular momentum hold the promise of providing a common “stellar Li depletion” explanation to the Li abundance patterns observed in all Galactic stellar populations, including the “dip” and the “plateau(s).” </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Novae are most probably the main source of Li in the Galaxy, on observational (but not yet theoretically established) grounds. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Radial migration of stars in the Galactic disk holds the key to understanding many aspects of the Li evolution in the Milky Way. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"48 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanohertz Gravitational Waves","authors":"Alberto Sesana, Daniel G. Figueroa","doi":"10.1146/annurev-astro-122325-025132","DOIUrl":"https://doi.org/10.1146/annurev-astro-122325-025132","url":null,"abstract":"Evidence of a gravitational wave (GW) signal has emerged in pulsar timing array (PTA) data, opening a new window into the nanohertz GW Universe. We explore the physics of GW signals that may explain the data, with a focus on GW backgrounds (GWBs) considering both astrophysical and cosmological origins. We describe how: <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> An astrophysical nanohertz GWB emerges as the superposition of individual signals from inspiraling massive black hole binaries. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Environment coupling, eccentricity, and sparse sampling cause great uncertainty in the theoretical prediction of the supermassive black hole signal but also offer a way to determine the origin of the signal. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> PTA data offer unprecedented opportunities to constrain high-energy physics beyond the Standard Model by probing early Universe GWBs that originated during or after inflation. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Different early Universe GWBs, typically created by nonlinear and out-of-equilibrium dynamics, can explain the PTA data (e.g., those from inflation scenarios, first-order phase transitions, or topological defects). </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The PTA detection of GWs opens a new window to explore the Universe, with profound implications for astrophysics and particle physics (probing, e.g., the equation of state of the early Universe, the origin of cosmological perturbations, the nature of dark matter, or whether exotic objects like primordial black holes or cosmic strings exist). </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precise Radial Velocities","authors":"Jennifer A. Burt, Xavier Dumusque, Samuel Halverson","doi":"10.1146/annurev-astro-120425-105551","DOIUrl":"https://doi.org/10.1146/annurev-astro-120425-105551","url":null,"abstract":"Precise measurements of a star's radial velocity (RV) made using extremely stable, high-resolution, optical or near-infrared spectrographs can be used to determine the masses and orbital parameters of gravitationally bound extrasolar planets (exoplanets). Indeed, RV surveys and follow-up efforts have provided the vast majority of published exoplanet mass measurements and, in doing so, have enabled studies of exoplanet interior and atmospheric compositions. We review the current state of the RV field, with particular attention to: <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> The evolution of precise RV methodologies over the past 2 decades. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Modern RV spectrograph designs that can be calibrated to a stability level of ≤50 cm s <jats:sup>−1</jats:sup> over timescales of years. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> RV data reduction and postprocessing techniques that minimize the impact of instrument systematics and stellar variability. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Techniques for detecting exoplanets in RV data and disentangling planetary signals from stellar variability. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"39 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The ALMA View of High-Redshift Galaxy Formation","authors":"Renske Smit, Rebecca A.A. Bowler","doi":"10.1146/annurev-astro-052722-104242","DOIUrl":"https://doi.org/10.1146/annurev-astro-052722-104242","url":null,"abstract":"The advent of routine operations with the Atacama Large Millimeter/submillimeter Array (ALMA) in the past decade has led to a revolution in the direct study of the interstellar medium (ISM) in “normal” high-redshift galaxies in the rest-frame far-infrared (FIR). This review summarizes the observational literature on <jats:italic>z</jats:italic> &gt; 6.5 sources observed with ALMA and NOEMA (NOrthern Extended Millimeter Array). The main findings are as follows: <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Cool gas consistently scales with star formation in a wide range of galaxy environments, similar to local relations, suggesting that fundamental processes of star formation have stayed relatively constant over 13 billion years of cosmic time. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Significant metal enrichment is present in galaxies just ∼300–400 million years after the Big Bang. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> There is a trend to a higher obscured fraction of star formation with stellar mass and star-formation rate (SFR) already in place at <jats:italic>z</jats:italic> <jats:inline-formula> <jats:tex-math>$simeq$</jats:tex-math> </jats:inline-formula> 7, with measurements of the cosmic SFR density showing that &gt;10% of the SFR density is obscured at this epoch. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The estimated dust masses compared to the stellar mass suggest that rapid dust enrichment occurs, likely from supernovae with little dust destruction and/or rapid growth in the ISM, which is in agreement maximal predictions from models. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> In individual sources, cold disks are already in existence, with their gas disks being more extended and smoother than their observed stellar counterparts. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"239 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Angular Momentum Transport in Protoplanetary Disks","authors":"Xue-Ning Bai","doi":"10.1146/annurev-astro-043024-115835","DOIUrl":"https://doi.org/10.1146/annurev-astro-043024-115835","url":null,"abstract":"We review our current understanding on the physical processes that govern angular momentum transport and evolution of protoplanetary disks. Extremely rich in physics, these processes are intimately connected to disk gas dynamics, with profound implications for planet formation. We organize them into a three-level hierarchical framework: <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> The coupling of gas with magnetic fields and radiation sets the microphysical foundation for understanding protoplanetary disk dynamics. Key ingredients include nonideal magnetohydrodynamics effects (requiring ionization chemistry), along with heating and cooling processes. The disk can be divided into three radial sectors governed by distinct microphysics. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Protoplanetary disks host diverse gas dynamical processes, including hydrodynamic, magnetic, and gravitational instabilities, along with thermally and magnetically driven disk winds. Many of these individual processes are reasonably well understood, whereas others still require detailed investigation. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Protoplanetary disks are highly complex ecosystems in which multiple processes interact. It is recognized that the bulk disk exhibits weak turbulence, with magnetically driven wind likely serving as the primary transport mechanism. However, our knowledge remains highly limited regarding the disk's innermost region, early stages, long-term evolution, and environmental effects. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"33 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148287777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding the Heliospheric Shield: Laying the Groundwork to Predict Habitable Astrospheres","authors":"Merav Opher","doi":"10.1146/annurev-astro-120425-053711","DOIUrl":"https://doi.org/10.1146/annurev-astro-120425-053711","url":null,"abstract":"This article reviews today's open issues, frontiers of research, and advances in our understanding of the heliosphere throughout the Sun's last 10 million years. Today's heliosphere, the cocoon formed by the solar wind as it moves through the Galaxy, engulfs all the planets extending in the nose direction to ∼120 astronomical units (AU). <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> The Sun moves at 19 pc/Myr and has traversed many different structures in the interstellar medium that affect the heliosphere, at times collapsing it to sub-astronomical-unit scales. These periods of collapse introduce climate and radiation changes in Earth's environment. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The frequency of such encounters could be as often as every couple of million years, making it a major external disturbance to the development of life on Earth. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Stepwise shifts in past global climate, seen in deep-sea sediment cores, indicate intervals of more rapid cooling at 13–14 Mya, 6–7 Mya, and 2–3 Mya, for which the driving mechanisms are subject to ongoing debate. Such cooling events might be triggered by heliosphere collapse. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"35 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148287794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quenching of Star Formation in Massive Galaxies","authors":"Katherine E. Whitaker, Rachel Bezanson","doi":"10.1146/annurev-astro-043024-121502","DOIUrl":"https://doi.org/10.1146/annurev-astro-043024-121502","url":null,"abstract":"The shutdown of star formation—quenching—marks a pivotal transition in the lives of massive galaxies, which dominate the present-day stellar mass density. This review synthesizes our current understanding of the mechanisms that trigger and maintain quiescence. We discuss the nuances of how quiescent systems are identified across cosmic time and summarize the evolving physical properties of the growing massive population, including their stellar populations, chemical enrichment histories, and gas and dust reservoirs, highlighting several key results: <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Quiescent galaxies can be identified with empirical color selections, but evolving specific star-formation rate thresholds offer a more robust physical distinction from star-forming systems. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The earliest massive quiescent stellar populations show rapid formation histories and high metallicities, with enhanced α-elemental abundances often distinct from local analogs. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Nascent studies of gas and dust in quiescent galaxies reveal diverse multiphase reservoirs and outflows, pointing to fast ejective and slow regulatory modes of galaxy quenching. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> In situ processes establish galaxy central density while assembly continues via (minor) mergers postquenching, reshaping all massive galaxies and disrupting rotation in most cases. </jats:list-item> </jats:list> We distill observations into two broad modes by which massive galaxies form and quench: One involves a rapid, early shutdown driven by supermassive black hole outflows on short timescales; the other proceeds gradually through gas exhaustion, virial heating, or preventative feedback, each leaving distinct observational signatures. Together, these pathways offer a testable framework for modeling the formation and evolution of massive galaxies, which will be informed by future studies of their stars, gas, dust, and dynamics.","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"34 1","pages":""},"PeriodicalIF":33.3,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148287123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Timing Mass of the Local Group","authors":"Louis E. Strigari","doi":"10.1146/annurev-astro-121024-051405","DOIUrl":"https://doi.org/10.1146/annurev-astro-121024-051405","url":null,"abstract":"The classic model of the Local Group (LG) is that of two dominant constituents, the Milky Way and M31, first separating and then detaching from the Hubble flow, leading to a nearly radial-approaching orbit. This simple model has been confronted by new measurements of the three-dimensional M31 kinematics, by cosmological simulations, and by theoretical understanding of the impact of massive substructures, such as the Large Magellanic Cloud. This article explores the consequences of new observations and theory on the determination of the mass and dynamics of the LG. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> The M31 tangential velocity measurement and contribution from the cosmological constant both increase the implied timing mass of the LG to be ∼5 × 10<jats:sup>12</jats:sup> M<jats:sub>⊙</jats:sub>. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Timing mass estimates for the LG tend to be greater than the sum of the Milky Way and M31 halo masses, and greater than independent LG mass estimators. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Precision future kinematics have the potential to explore the origin of this difference and shed light on dark matter in the LG, the origin of its angular momentum, and possibly even local values of cosmological parameters. </jats:list-item> </jats:list>","PeriodicalId":8138,"journal":{"name":"Annual Review of Astronomy and Astrophysics","volume":"51 1","pages":"431-466"},"PeriodicalIF":33.3,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}