Pablo Martínez-Miravé, Irene Tamborra and Alejandro Vigna-Gómez
{"title":"Identifying Thorne–Żytkow Objects through Neutrinos","authors":"Pablo Martínez-Miravé, Irene Tamborra and Alejandro Vigna-Gómez","doi":"10.3847/2041-8213/adc8ab","DOIUrl":"https://doi.org/10.3847/2041-8213/adc8ab","url":null,"abstract":"Thorne–Żytkow objects (T Os) have been predicted to form when a neutron star is engulfed by a diffuse, convective giant envelope. Accretion onto a neutron star at a rate that is larger than 10−4M⊙ yr−1 is expected to lead to significant emission of neutrinos of all flavors with energy of 1–100 MeV. Since the neutrino signal is expected to largely vary in time (from milliseconds to thousands of years), we outline detection strategies tailored to the signal duration. We find that neutrino detection from T Os up to the Small Magellanic Cloud is within the reach of current- and next-generation neutrino observatories, such as Super- and Hyper-Kamiokande, the IceCube Neutrino Observatory, and JUNO. Interestingly, if targeted searches for neutrinos from T O candidates (e.g., VX Sgr in our Galaxy as well as HV 2112 and HV 11417 in the Small Magellanic Cloud) should lead to positive results, neutrinos could positively identify the nature of such sources and their accretion rate. Furthermore, the diffuse supernova neutrino background may be able to rule out extreme scenarios for the formation and accretion rates of TŻOs. Our findings should serve as motivation for establishing dedicated searches for neutrino emission from T Os. This is especially timely since it is challenging to detect TŻOs via electromagnetic radiation unambiguously, and the T O gravitational-wave signal could be probed with next-generation detectors for sources within our Galaxy only.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anisha Sen, S. P. Rajaguru, Abhinav Govindan Iyer, Ruizhu Chen, Junwei Zhao and Shukur Kholikov
{"title":"Solar Cycle Variations in Meridional Flows and Rotational Shear within the Sun’s Near-surface Shear Layer","authors":"Anisha Sen, S. P. Rajaguru, Abhinav Govindan Iyer, Ruizhu Chen, Junwei Zhao and Shukur Kholikov","doi":"10.3847/2041-8213/adc919","DOIUrl":"https://doi.org/10.3847/2041-8213/adc919","url":null,"abstract":"Using solar cycle–long helioseismic measurements of meridional and zonal flows in the near-surface shear layer (NSSL) of the Sun, we study their spatiotemporal variations and connections to active regions. We find that near-surface inflows toward active latitudes are part of a local circulation with an outflow away from them at depths around 0.97 R⊙, which is also the location where the deviations in the radial gradient of rotation change sign. These results, together with opposite signed changes, over latitude and depth, in the above quantities observed during the solar minimum period, point to the action of the Coriolis force on large-scale flows as the primary cause of changes in rotation gradient within the NSSL. We also find that such Coriolis force mediated changes in near-surface flows toward active latitudes only marginally change the amplitude of zonal flow and hence are not likely to be its driving force. Our measurements typically achieve a high signal-to-noise ratio (>5σ) for near-surface flows but can drop to 3σ near the base (0.95 R⊙) of the NSSL. Close agreements between the depth profiles of changes in rotation gradient and in meridional flows measured from quite different global and local helioseismic techniques, respectively, show that the results are not dependent on the analysis techniques.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marc Hon, Saul Rappaport, Avi Shporer, Andrew Vanderburg, Karen A. Collins, Cristilyn N. Watkins, Richard P. Schwarz, Khalid Barkaoui, Samuel W. Yee, Joshua N. Winn, Alex S. Polanski, Emily A. Gilbert, David R. Ciardi, Jeroen Audenaert, William Fong, Jack Haviland, Katharine Hesse, Daniel Muthukrishna, Glen Petitpas, Ellie Hadjiyska Schmelzer, Norio Narita, Akihiko Fukui, Sara Seager and George R. Ricker
{"title":"A Disintegrating Rocky Planet with Prominent Comet-like Tails around a Bright Star","authors":"Marc Hon, Saul Rappaport, Avi Shporer, Andrew Vanderburg, Karen A. Collins, Cristilyn N. Watkins, Richard P. Schwarz, Khalid Barkaoui, Samuel W. Yee, Joshua N. Winn, Alex S. Polanski, Emily A. Gilbert, David R. Ciardi, Jeroen Audenaert, William Fong, Jack Haviland, Katharine Hesse, Daniel Muthukrishna, Glen Petitpas, Ellie Hadjiyska Schmelzer, Norio Narita, Akihiko Fukui, Sara Seager and George R. Ricker","doi":"10.3847/2041-8213/adbf21","DOIUrl":"https://doi.org/10.3847/2041-8213/adbf21","url":null,"abstract":"We report the discovery of BD+05 4868 Ab, a transiting exoplanet orbiting a bright (V = 10.16) K-dwarf (TIC 466376085) with a period of 1.27 days. Observations from NASA’s Transiting Exoplanet Survey Satellite reveal variable transit depths and asymmetric transit profiles that are characteristic of comet-like tails formed by dusty effluents emanating from a disintegrating planet. Unique to BD+05 4868 Ab is the presence of prominent dust tails in both the trailing and leading directions that contribute to the extinction of starlight from the host star. By fitting the observed transit profile and analytically modeling the drift of dust grains within both dust tails, we infer large grain sizes (∼1–10 μm) and a mass-loss rate of 10 M⊕ Gyr−1, suggestive of a lunar-mass object with a disintegration timescale of only several Myr. The host star is probably older than the Sun and is accompanied by an M-dwarf companion at a projected physical separation of 130 au. The brightness of the host star, combined with the planet’s relatively deep transits (0.8%–2.0%), presents BD+05 4868 Ab as a prime target for compositional studies of rocky exoplanets and investigations into the nature of catastrophically evaporating planets.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jace Rusznak, Xian-Yu Wang, Malena Rice and Songhu Wang
{"title":"From Misaligned Sub-Saturns to Aligned Brown Dwarfs: The Highest M p /M * Systems Exhibit Low Obliquities, Even around Hot Stars*","authors":"Jace Rusznak, Xian-Yu Wang, Malena Rice and Songhu Wang","doi":"10.3847/2041-8213/adc129","DOIUrl":"https://doi.org/10.3847/2041-8213/adc129","url":null,"abstract":"We present a pattern emerging from stellar obliquity measurements in single-star systems: planets with high planet-to-star mass ratios (MP/M* ≥ 2 × 10−3)—such as super-Jupiters, brown dwarf companions, and M dwarfs hosting Jupiter-like planets—tend to be aligned, even around hot stars. This alignment represents a 3.7σ deviation from the obliquity distribution observed in systems with lower mass ratios (MP/M* < 2 × 10−3), which predominantly include Jupiters and sub-Saturns. The only known outlier system, XO-3, exhibits misalignment confirmed via our newly collected Rossiter–McLaughlin effect measurement (λ = ). However, the relatively large Gaia renormalized unit weight error of XO-3 suggests that it may harbor an undetected binary companion, potentially contributing to its misalignment. Given that tidal realignment mechanisms are weak for hot stars, the observed alignment in high MP/M* systems is likely primordial rather than resulting from tidal interactions. One possible explanation is that only dynamically isolated planets can continue accreting gas and evolve into super-Jupiters while maintaining their primordial alignment. Conversely, planets formed in compact configurations may be unable to grow beyond the gap-opening mass, for which our work suggests an empirical boundary MP/M* = 2 × 10−3 identified between aligned high MP/M* systems and misaligned low MP/M* systems, with dynamical instabilities contributing to the diverse spin–orbit misalignments observed in the latter.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nikku Madhusudhan, Savvas Constantinou, Måns Holmberg, Subhajit Sarkar, Anjali A. A. Piette and Julianne I. Moses
{"title":"New Constraints on DMS and DMDS in the Atmosphere of K2-18 b from JWST MIRI","authors":"Nikku Madhusudhan, Savvas Constantinou, Måns Holmberg, Subhajit Sarkar, Anjali A. A. Piette and Julianne I. Moses","doi":"10.3847/2041-8213/adc1c8","DOIUrl":"https://doi.org/10.3847/2041-8213/adc1c8","url":null,"abstract":"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 first detections of the carbon-bearing molecules CH4 and CO2 in its atmosphere, with a composition consistent with predictions for hycean conditions. The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance. We report a mid-infrared transmission spectrum of K2-18 b obtained using the JWST MIRI LRS instrument in the ∼6–12 μm range. The spectrum shows distinct features and is inconsistent with a featureless spectrum at 3.4σ significance compared to our canonical model. We find that the spectrum cannot be explained by most molecules predicted for K2-18 b, with the exception of DMS and dimethyl disulfide (DMDS), also a potential biosignature gas. We report new independent evidence for DMS and/or DMDS in the atmosphere at 3σ significance, with high abundance (≳10 ppmv) of at least one of the two molecules. More observations are needed to increase the robustness of the findings and resolve the degeneracy between DMS and DMDS. The results also highlight the need for additional experimental and theoretical work to determine accurate cross sections of important biosignature gases and identify potential abiotic sources. We discuss the implications of the present findings for the possibility of biological activity on K2-18 b.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rena A. Lee, Fei Dai, Andrew W. Howard, Samuel Halverson, Jonathan Gomez Barrientos, Michael Greklek-McKeon, Heather A. Knutson, Benjamin J. Fulton, Guđmundur Stefánsson, Jack Lubin, Howard Isaacson, Casey L. Brinkman, Nicholas Saunders, Daniel Hey, Daniel Huber, Lauren M. Weiss, Leslie A. Rogers, Diana Valencia, Mykhaylo Plotnykov, Kimberly Paragas, Renyu Hu, Te Han, Erik A. Petigura, Ryan Rubenzahl, David R. Ciardi, Aaron Householder, Gregory J. Gilbert, J. M. Joel Ong, Jingwen Zhang, Jacob Luhn, Luke Handley, Corey Beard, Steven Giacalone, Rae Holcomb, Judah Van Zandt, Ashley D. Baker, Max Brodheim, Matt Brown, David Charbonneau, Karen A. Collins, Ian J. M. Crossfield, William Deich, Xavier Dumusque, Steven R. Gibson, Emily Gilbert, Grant M. Hill, Bradford Holden, Jon M. Jenkins, Stephen Kaye, Russ R. Laher, Kyle Lanclos, W. Garett Levine, Joel Payne, Alex S. Polanski, John O’Meara, George R. Ricker, Kodi Rider, Paul Robertson, Arpita Roy, Joshua E. Schlieder, Christian Sc..
{"title":"TOI-6324 b: An Earth-mass Ultra-short-period Planet Transiting a Nearby M Dwarf","authors":"Rena A. Lee, Fei Dai, Andrew W. Howard, Samuel Halverson, Jonathan Gomez Barrientos, Michael Greklek-McKeon, Heather A. Knutson, Benjamin J. Fulton, Guđmundur Stefánsson, Jack Lubin, Howard Isaacson, Casey L. Brinkman, Nicholas Saunders, Daniel Hey, Daniel Huber, Lauren M. Weiss, Leslie A. Rogers, Diana Valencia, Mykhaylo Plotnykov, Kimberly Paragas, Renyu Hu, Te Han, Erik A. Petigura, Ryan Rubenzahl, David R. Ciardi, Aaron Householder, Gregory J. Gilbert, J. M. Joel Ong, Jingwen Zhang, Jacob Luhn, Luke Handley, Corey Beard, Steven Giacalone, Rae Holcomb, Judah Van Zandt, Ashley D. Baker, Max Brodheim, Matt Brown, David Charbonneau, Karen A. Collins, Ian J. M. Crossfield, William Deich, Xavier Dumusque, Steven R. Gibson, Emily Gilbert, Grant M. Hill, Bradford Holden, Jon M. Jenkins, Stephen Kaye, Russ R. Laher, Kyle Lanclos, W. Garett Levine, Joel Payne, Alex S. Polanski, John O’Meara, George R. Ricker, Kodi Rider, Paul Robertson, Arpita Roy, Joshua E. Schlieder, Christian Sc..","doi":"10.3847/2041-8213/adadd7","DOIUrl":"https://doi.org/10.3847/2041-8213/adadd7","url":null,"abstract":"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 of any thick H/He envelope. We were able to constrain its interior composition and found an iron-core mass fraction (CMF = 27% ± 37%) consistent with that of Earth (∼33%) and other confirmed USPs. TOI-6324 b is the closest to an Earth-sized USP confirmed to date. TOI-6324 b is a promising target for JWST phase-curve and secondary eclipse observations (emission spectroscopy metric = 25), which may reveal its surface mineralogy, day–night temperature contrast, and possible tidal deformation. From seven sectors of TESS data, we report a tentative detection of the optical phase-curve variation with an amplitude of 42 ± 28 ppm.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
De-Chao Song, Marie Dominique, Ivan Zimovets, Qiao Li, Ying Li, Fu Yu, Yang Su, B. A. Nizamov, Ya Wang, Andrea Francesco Battaglia, Jun Tian, Li Feng, Hui Li and W. Q. Gan
{"title":"Unveiling Spatiotemporal Properties of the Quasiperiodic Pulsations in the Balmer Continuum at 3600 Å in an X-class Solar White-light Flare","authors":"De-Chao Song, Marie Dominique, Ivan Zimovets, Qiao Li, Ying Li, Fu Yu, Yang Su, B. A. Nizamov, Ya Wang, Andrea Francesco Battaglia, Jun Tian, Li Feng, Hui Li and W. Q. Gan","doi":"10.3847/2041-8213/adc4e9","DOIUrl":"https://doi.org/10.3847/2041-8213/adc4e9","url":null,"abstract":"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 Solar Observatory, with high-cadence imaging (1–2 s) in the Balmer continuum at 3600 Å. Combined with additional multi-instrument data, we find that the enhancement of the WLF in both Balmer and Paschen continua shows strong spatiotemporal correlation with hard X-ray (HXR) emissions. Notably, the pulses in the WST Balmer continuum exhibited a near-zero time lag with most HXR pulses, whereas soft X-ray and extreme ultraviolet emissions showed a lag of 2–3 s. Interestingly, quasi-harmonic QPPs with periods of ∼11 and ∼20 s were observed in multiple wavelengths in the rising phase of the white-light continuum. Furthermore, we employed Fourier transform to spatially locate the QPPs around 11 and 20 s, revealing that they primarily originated from the east flare ribbon, which exhibited the most substantial continuum enhancement. More interestingly, we find that the west ribbon contributed significantly to the 11 s QPP but had a weaker contribution to the 20 s QPP. Moreover, the occurrence of quasi-harmonic QPPs is temporally coincident with the rapid elongation and separation motions of flare ribbons. Possible mechanisms for the quasi-harmonic QPPs have been discussed. These observations provide valuable insights into QPP modeling for solar and stellar flares.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haojie Hu, Kohei Inayoshi, Zoltán Haiman, Luis C. Ho and Ken Ohsuga
{"title":"The Convergence of Heavy and Light Seeds to Overmassive Black Holes at Cosmic Dawn","authors":"Haojie Hu, Kohei Inayoshi, Zoltán Haiman, Luis C. Ho and Ken Ohsuga","doi":"10.3847/2041-8213/adc680","DOIUrl":"https://doi.org/10.3847/2041-8213/adc680","url":null,"abstract":"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 accretion. We present a growth model coupled with dark matter halo assembly to explore the evolution of the MBH/M⋆ ratio under different seeding and feedback scenarios. Given the gas inflow rates in protogalaxies, BHs grow episodically at moderate super-Eddington rates, and the mass ratio increases early on, despite significant mass loss through feedback. Regardless of seeding mechanisms, the mass ratio converges to a universal value ∼0.1–0.3, set by the balance between gas feeding and star formation efficiency in the nucleus. This behavior defines an attractor in the MBH–M⋆ diagram, where overmassive BHs grow more slowly than their hosts, while undermassive seeds experience rapid growth before aligning with the attractor. We derive an analytical expression for the universal mass ratio, linking it to feedback strength and halo growth. The convergence of evolutionary tracks erases seeding information from the mass ratio by z ∼ 4–6. Detecting BHs with ∼105−6M⊙ at higher redshifts that deviate from the convergence trend would provide key diagnostics of their birth conditions.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joheen Chakraborty, Erin Kara, Riccardo Arcodia, Johannes Buchner, Margherita Giustini, Lorena Hernández-García, Itai Linial, Megan Masterson, Giovanni Miniutti, Andrew Mummery, Christos Panagiotou, Erwan Quintin and Paula Sánchez-Sáez
{"title":"Discovery of Quasiperiodic Eruptions in the Tidal Disruption Event and Extreme Coronal Line Emitter AT2022upj: Implications for the QPE/TDE Fraction and a Connection to ECLEs","authors":"Joheen Chakraborty, Erin Kara, Riccardo Arcodia, Johannes Buchner, Margherita Giustini, Lorena Hernández-García, Itai Linial, Megan Masterson, Giovanni Miniutti, Andrew Mummery, Christos Panagiotou, Erwan Quintin and Paula Sánchez-Sáez","doi":"10.3847/2041-8213/adc2f8","DOIUrl":"https://doi.org/10.3847/2041-8213/adc2f8","url":null,"abstract":"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 from 0.5–3.5 days, durations from 0.3–1 days, peak luminosities from 1042.5−43.0 erg s−1, and erratic flare profiles. A wealth of evidence now links at least some QPEs to the newly formed accretion flows emerging from TDEs; AT2022upj is the third QPE reported in an optically discovered TDE. Marginalizing over the uncertain distributions of QPE peak luminosity, recurrence time, delay after TDE peak, and lifetime, we use the burgeoning sample to make a Bayesian estimate that the fraction of optical TDEs resulting in QPEs within 5 yr post-disruption is %. Along with AT2019qiz, AT2022upj also marks the second of the three optical TDE+X-ray QPEs showing coronal line emission, suggesting ECLEs may represent a subset of TDEs particularly efficient at forming QPEs and/or that sustained QPE X-ray emission contributes to coronal line emission in some galactic nuclei.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Angular Momentum Transport by Internal Gravity Waves across Age","authors":"T. M. Rogers and R. P. Ratnasingam","doi":"10.3847/2041-8213/adc45a","DOIUrl":"https://doi.org/10.3847/2041-8213/adc45a","url":null,"abstract":"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 attenuated. This, coupled with the changing stratification throughout the radiation zone, leads to significantly reduced angular momentum transport at later stages on the main sequence. Indeed the angular momentum transport at mid–main sequence is typically 3–4 orders of magnitude lower than at zero age, though we expect this to be somewhat mitigated by the chemical mixing also induced by such waves. We provide measures of the angular momentum transport, both in terms of the divergence of the Reynolds stress and a typical “wave luminosity.” However, we caution that the angular momentum transport drives shear flows, resulting in both slowing and speeding up of radiative interiors. While the values of Reynolds stress and angular momentum transport are only within the context of these limited simulations, they are not significantly different to those found previously using simpler prescriptions, providing some confidence in their applicability.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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