The Astrophysical Journal Letters最新文献_第3页

Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy

The Astrophysical Journal Letters Pub Date : 2024-12-11 DOI: 10.3847/2041-8213/ad92f9

Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack and Jean-Baptiste Ruffio

{"title":"Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy","authors":"Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack and Jean-Baptiste Ruffio","doi":"10.3847/2041-8213/ad92f9","DOIUrl":"https://doi.org/10.3847/2041-8213/ad92f9","url":null,"abstract":"We present JWST/Mid Infrared Instrument (MIRI) low-resolution spectroscopy (4.75–14 μm) of the first known substellar companion, Gliese 229Bab, which was recently resolved into a tight binary brown dwarf. Previous atmospheric retrieval studies modeling Gliese 229B as a single brown dwarf have reported anomalously high carbon-to-oxygen ratios (C/O) of ≈1.1 using 1–5 μm ground-based spectra. Here, we fit the MIRI spectrum of Gliese 229Bab with a two-component binary model using the Sonora Elf Owl grid and additionally account for the observed K-band flux ratio of the binary brown dwarf. Assuming the two brown dwarfs share the same abundances, we obtain C/O = 0.65 ± 0.05 and as their abundances (2σ statistical errors), which are fully consistent with the host star abundances. We also recover the same abundances if we fit the MIRI spectrum with a single brown dwarf model, indicating that binarity does not strongly affect inferred abundances from mid-infrared data when the Teff are similar between components of the binary. In addition, we measure K and K for the two brown dwarfs. We find that the vertical diffusion coefficients of are identical between the two brown dwarfs and in line with values inferred for isolated brown dwarfs of similar Teff. Our results demonstrate the power of mid-infrared spectroscopy in providing robust atmospheric abundance measurements for brown dwarf companions and, by extension, giant planets.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809648","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}

引用次数: 0

ALMA Detection of [O iii] 88 μm at z = 12.33: Exploring the Nature and Evolution of GHZ2 as a Massive Compact Stellar System

The Astrophysical Journal Letters Pub Date : 2024-12-10 DOI: 10.3847/2041-8213/ad8f38

Jorge A. Zavala, Tom Bakx, Ikki Mitsuhashi, Marco Castellano, Antonello Calabro, Hollis Akins, Veronique Buat, Caitlin M. Casey, David Fernandez-Arenas, Maximilien Franco, Adriano Fontana, Bunyo Hatsukade, Luis C. Ho, Ryota Ikeda, Jeyhan Kartaltepe, Anton M. Koekemoer, Jed McKinney, Lorenzo Napolitano, Pablo G. Pérez-González, Paola Santini, Stephen Serjeant, Elena Terlevich, Roberto Terlevich and L. Y. Aaron Yung

{"title":"ALMA Detection of [O iii] 88 μm at z = 12.33: Exploring the Nature and Evolution of GHZ2 as a Massive Compact Stellar System","authors":"Jorge A. Zavala, Tom Bakx, Ikki Mitsuhashi, Marco Castellano, Antonello Calabro, Hollis Akins, Veronique Buat, Caitlin M. Casey, David Fernandez-Arenas, Maximilien Franco, Adriano Fontana, Bunyo Hatsukade, Luis C. Ho, Ryota Ikeda, Jeyhan Kartaltepe, Anton M. Koekemoer, Jed McKinney, Lorenzo Napolitano, Pablo G. Pérez-González, Paola Santini, Stephen Serjeant, Elena Terlevich, Roberto Terlevich and L. Y. Aaron Yung","doi":"10.3847/2041-8213/ad8f38","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8f38","url":null,"abstract":"We present Atacama Large Millimeter/submillimeter Array observations on the high-redshift galaxy GHZ2 and report a successful detection of the rest-frame 88 μm atomic transition from doubly ionized oxygen at z = 12.3327 ± 0.0035. Based on these observations, combined with additional constraints on the [O iii] 52 μm line luminosity and previous JWST data, we argue that GHZ2 is likely powered by compact and young star formation and show that it follows well-established relationships found for giant H ii regions and metal-poor star-forming dwarf galaxies that are known to host bright super star clusters. Additionally, these observations provide new constraints on the oxygen electron density (100 ≲ ne [cm−3] ≲ 4,000) and dynamical mass (Mdyn ≈ 3–8 × 108M⊙). The existence of these massive starburst systems 13.3 Gyr ago might explain the origin of today’s globular clusters, a long-standing question in astronomy. To test this, we present observational probes to investigate whether sources like GHZ2 are linked to the formation of today’s globular clusters or other more massive compact stellar systems.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809835","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}

引用次数: 0

A Magnetic Pressure Difference Rule on Moving Bipolar Pores

The Astrophysical Journal Letters Pub Date : 2024-12-10 DOI: 10.3847/2041-8213/ad9469

Merlin Malonzo Mendoza and Chia-Hsien Lin

引用次数: 0

On the Geometry of the Near-core Magnetic Field in Massive Stars

The Astrophysical Journal Letters Pub Date : 2024-12-10 DOI: 10.3847/2041-8213/ad95f8

R. P. Ratnasingam, P. V. F. Edelmann, D. M. Bowman and T. M. Rogers

{"title":"On the Geometry of the Near-core Magnetic Field in Massive Stars","authors":"R. P. Ratnasingam, P. V. F. Edelmann, D. M. Bowman and T. M. Rogers","doi":"10.3847/2041-8213/ad95f8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad95f8","url":null,"abstract":"It is well-known that the cores of massive stars sustain a stellar dynamo with a complex magnetic field configuration. However, the same cannot be said for the field's strength and geometry at the convective–radiative boundary, which are crucial when performing asteroseismic inference. In this Letter, we present 3D magnetohydrodynamic (MHD) simulations of a 7 M⊙ mid-main-sequence star, with particular attention given to the convective–radiative boundary in the near-core region. Our simulations reveal that the toroidal magnetic field is significantly stronger than the poloidal field in this region, contrary to recent assumptions. Moreover, the rotational shear layer, also important for asteroseismic inference, is specifically confined within the extent of the Brunt–Väisälä frequency peak. These results, which are based on the inferred properties of HD 43317, have widespread implications for asteroseismic studies of rotation, mixing, and magnetism in stars. While we expect our results to be broadly applicable across stars with similar Brunt–Väisälä frequency profiles and stellar masses, we also expect the MHD parameters (e.g., Rem) and the initial stellar rotation rate to impact the geometry of the field and differential rotation at the convective–radiative interface.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142805435","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}

引用次数: 0

An Eccentric Binary with a Misaligned Circumbinary Disk

The Astrophysical Journal Letters Pub Date : 2024-12-06 DOI: 10.3847/2041-8213/ad94e8

Zhecheng Hu, 哲程胡, Wei Zhu, 伟祝, Fei Dai, 飞戴, Ping Chen, 平陈, Yang Huang, 样黄, Min Fang, 敏房 and Richard S. Post

{"title":"An Eccentric Binary with a Misaligned Circumbinary Disk","authors":"Zhecheng Hu, 哲程胡, Wei Zhu, 伟祝, Fei Dai, 飞戴, Ping Chen, 平陈, Yang Huang, 样黄, Min Fang, 敏房 and Richard S. Post","doi":"10.3847/2041-8213/ad94e8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad94e8","url":null,"abstract":"We present spectroscopic and photometric observations of Bernhard-2, which was previously identified as a candidate system that hosts a misaligned circumbinary disk. Our spectroscopic measurements confirm that Bernhard-2 indeed contains an eccentric (e = 0.69 ± 0.08) binary and thus that the periodic variability in the photometric light curve is best explained by the occultation by the misaligned circumbinary disk. By modeling the spectral energy distributions at different phases, we infer the masses of the two binary components to be ∼1.1 M⊙ and ∼0.9 M⊙, respectively. The system age is determined to be ≲20 Myr by combining the stellar isochrone model with lithium abundance. Our new photometric observations show clear deviations from the model prediction based on the archival data, suggesting ongoing precession of the circumbinary disk. The Hα line of Bernhard-2 also shows an inverse P-Cygni profile at epochs close to the pericenter passage, which could be attributed to the pulsed accretion around the pericenter. Bernhard-2 therefore closely resembles the well-studied KH 15D system. Further detailed observations and studies of such rare systems can provide useful information about disk physics and evolution.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793879","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}

引用次数: 0

131 and 304 Å Emission Variability Increases Hours Prior to Solar Flare Onset

The Astrophysical Journal Letters Pub Date : 2024-12-06 DOI: 10.3847/2041-8213/ad94dd

Kara L. Kniezewski, E. I. Mason, Vadim M. Uritsky and Seth H. Garland

{"title":"131 and 304 Å Emission Variability Increases Hours Prior to Solar Flare Onset","authors":"Kara L. Kniezewski, E. I. Mason, Vadim M. Uritsky and Seth H. Garland","doi":"10.3847/2041-8213/ad94dd","DOIUrl":"https://doi.org/10.3847/2041-8213/ad94dd","url":null,"abstract":"Thermal changes in coronal loops are well studied, both in quiescent active regions and in flaring scenarios. However, relatively little attention has been paid to loop emission in the hours before the onset of a solar flare; here, we present the findings of a study of over 50 off-limb flares of Geostationary Operational Environmental Satellite class C5.0 and above. We investigated the integrated emission variability for Solar Dynamics Observatory Atmospheric Imaging Assembly channels 131, 171, 193, and 304 Å for 6 hr before each flare and compared these quantities to the same time range and channels above active regions without proximal flaring. We find significantly increased emission variability in the 2–3 hr before flare onset, particularly for the 131 and 304 channels. This finding suggests a potential new flare prediction methodology. The emission trends between the channels are not consistently well correlated, suggesting a somewhat chaotic thermal environment within the coronal portion of the loops that disturbs the commonly observed heating and cooling cycles of quiescent active region loops. We present our approach and the resulting statistics and discuss the implications for heating sources in these preflaring active regions.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793900","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}

引用次数: 0

Comprehensive Study of Near-Earth Asteroid 2024 MK: Testing Planetary Encounters as a Source for Surface Refreshing

The Astrophysical Journal Letters Pub Date : 2024-12-06 DOI: 10.3847/2041-8213/ad9728

Lauren E. McGraw, Cristina A. Thomas, Tim A. Lister, Becky J. Williams, Andy S. Rivkin, Bryan Holler and Leslie A. Young

{"title":"Comprehensive Study of Near-Earth Asteroid 2024 MK: Testing Planetary Encounters as a Source for Surface Refreshing","authors":"Lauren E. McGraw, Cristina A. Thomas, Tim A. Lister, Becky J. Williams, Andy S. Rivkin, Bryan Holler and Leslie A. Young","doi":"10.3847/2041-8213/ad9728","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9728","url":null,"abstract":"Near-Earth object 2024 MK was discovered on 2024 June 16, less than 2 weeks before it made a sub-lunar-distance close approach. This close approach provided an ideal opportunity to determine how planetary encounters affect asteroid surfaces in preparation for the numerous missions to (99942) Apophis during its close approach in 2029. We collected spectroscopic data before and after its close approach to determine if planetary encounters induce spectral changes due to surface refreshing. We used NASA’s Infrared Telescope Facility’s (IRTF) near-infrared spectrometer SpeX prism mode (0.7–2.5 μm) to observe 2024 MK pre and postapproach. We also observed the asteroid before its close approach using Las Cumbres Observatory’s FLOYDS visible spectrometer and after its close approach using IRTF’s SpeX long-wavelength cross-dispersed short grating mode, resulting in full spectral coverage from 0.32 to 4.2 μm. 2024 MK is an S-type asteroid that is compositionally most analogous to an L-ordinary chondrite. Spectral analysis of the 3 μm region indicates no surficial water or hydroxide within the level of noise. Band parameter analysis of the pre and postapproach data shows the planetary encounter did not induce any significant spectral changes, suggesting that surface refreshing did not occur on a measurable scale. Similar studies of other targets at smaller encounter distances are required to determine if the lack of spectral changes on 2024 MK indicates it was not close enough to Earth to affect its surface or if the spectral similarity pre and postapproach instead indicates planetary encounters do not cause surface refreshing.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793866","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}

引用次数: 0

Theoretical Studies on the Evolution of Solar Filaments in Response to New Emerging Flux

The Astrophysical Journal Letters Pub Date : 2024-12-06 DOI: 10.3847/2041-8213/ad94ea

Yuhao Chen, Jialiang Hu, Guanchong Cheng, Jing Ye, Zhixing Mei, Chengcai Shen and Jun Lin

{"title":"Theoretical Studies on the Evolution of Solar Filaments in Response to New Emerging Flux","authors":"Yuhao Chen, Jialiang Hu, Guanchong Cheng, Jing Ye, Zhixing Mei, Chengcai Shen and Jun Lin","doi":"10.3847/2041-8213/ad94ea","DOIUrl":"https://doi.org/10.3847/2041-8213/ad94ea","url":null,"abstract":"New emerging flux (NEF) has long been considered a mechanism for solar eruptions, but the detailed process remains an open question. In this work, we explore how NEF drives a coronal magnetic configuration to erupt. This configuration is created by two magnetic sources of strengths M and S embedded in the photosphere, one electric-current-carrying flux rope (FR) floating in the corona, and an electric current induced on the photospheric surface by the FR. The source M is fixed, accounting for the initial background field, and S changes, playing the role of NEF. We introduce the channel function C to forecast the overall evolutionary behavior of the configuration. The location, polarity, and strength of NEF govern the evolutionary behavior of the FR before eruption. In the case of ∣S/M∣ < 1, with reconnection occurring between new and old fields, the configuration in equilibrium evolves to the critical state, invoking the catastrophe. In this case, if the polarities of the new and old fields are opposite, reconnection occurs as NEF is close to the FR, and if the polarities are the same, reconnection happens as NEF appears far from the FR. With different combinations of the relative polarity and the location, the evolutionary behavior of the system gets complex, and the catastrophe may not occur. If ∣S/M∣ > 1 and the two fields have opposite polarity, the catastrophe always takes place, but if the polarities are the same, the catastrophe occurs only as NEF is located far from the FR; otherwise, the evolution ends up either with a failed eruption or without a catastrophe at all.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142793865","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}

引用次数: 0

The Small Sizes and High Implied Densities of “Little Red Dots” with Balmer Breaks Could Explain Their Broad Emission Lines without an Active Galactic Nucleus

The Astrophysical Journal Letters Pub Date : 2024-12-06 DOI: 10.3847/2041-8213/ad90b8

Josephine F. W. Baggen, Pieter van Dokkum, Gabriel Brammer, Anna de Graaff, Marijn Franx, Jenny Greene, Ivo Labbé, Joel Leja, Michael V. Maseda, Erica J. Nelson, Hans-Walter Rix, Bingjie Wang, 冰洁王 and Andrea Weibel

{"title":"The Small Sizes and High Implied Densities of “Little Red Dots” with Balmer Breaks Could Explain Their Broad Emission Lines without an Active Galactic Nucleus","authors":"Josephine F. W. Baggen, Pieter van Dokkum, Gabriel Brammer, Anna de Graaff, Marijn Franx, Jenny Greene, Ivo Labbé, Joel Leja, Michael V. Maseda, Erica J. Nelson, Hans-Walter Rix, Bingjie Wang, 冰洁王 and Andrea Weibel","doi":"10.3847/2041-8213/ad90b8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad90b8","url":null,"abstract":"Early JWST studies found an apparent population of massive, compact galaxies at redshifts z ≳ 7. Recently three of these galaxies were shown to have prominent Balmer breaks, demonstrating that their light at λrest ∼ 3500 Å is dominated by a stellar population that is relatively old (∼200 Myr). All three also have broad Hβ emission with σ > 1000 km s−1, a common feature of such “little red dots.” From Sérsic profile fits to the Near Infrared Camera images in F200W we find that the stellar light of galaxies is extremely compact: the galaxies have half-light radii of re ∼ 100 pc, in the regime of ultracompact dwarfs in the nearby Universe. Their masses are uncertain, as they depend on the contribution of possible light from an active galactic nucleus (AGN) to the flux at λrest > 5000 Å. If the AGN contribution is low beyond the Balmer break region, the masses are M* ∼ 1010–1011 M☉, and the central densities are higher than those of any other known galaxy population by 1 order of magnitude. Interestingly, the implied velocity dispersions of ∼1500 km s−1 are in very good agreement with the measured Hβ line widths. We suggest that some of the broad lines in “little red dots” are not due to AGNs, but simply reflect the kinematics of the galaxies, and speculate that the galaxies are observed in a short-lived phase where the central densities are much higher than at later times. We stress, however, that the canonical interpretation of AGNs causing the broad Hβ lines also remains viable.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"220 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788411","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}

引用次数: 0

Detection of the Orbital Modulation of Fe Kα Fluorescence Emission in Centaurus X-3 Using the High-resolution Spectrometer Resolve on board XRISM

The Astrophysical Journal Letters Pub Date : 2024-12-05 DOI: 10.3847/2041-8213/ad946d

Yuto Mochizuki, Masahiro Tsujimoto, Richard L. Kelley, Bert Vander Meulen, Teruaki Enoto, Yutaro Nagai, Chris Done, Pragati Pradhan, Natalie Hell, Katja Pottschmidt, Ken Ebisawa and Ehud Behar

{"title":"Detection of the Orbital Modulation of Fe Kα Fluorescence Emission in Centaurus X-3 Using the High-resolution Spectrometer Resolve on board XRISM","authors":"Yuto Mochizuki, Masahiro Tsujimoto, Richard L. Kelley, Bert Vander Meulen, Teruaki Enoto, Yutaro Nagai, Chris Done, Pragati Pradhan, Natalie Hell, Katja Pottschmidt, Ken Ebisawa and Ehud Behar","doi":"10.3847/2041-8213/ad946d","DOIUrl":"https://doi.org/10.3847/2041-8213/ad946d","url":null,"abstract":"The Fe Kα fluorescence line emission in X-ray spectra is a powerful diagnostic tool for various astrophysical objects to reveal the distribution of cold matter around photoionizing sources. The advent of the X-ray microcalorimeter on board the XRISM satellite will bring new constraints on the emission line. We present one of the first such results for the high-mass X-ray binary Centaurus X-3, which is composed of an O-type star and a neutron star (NS). We conducted a 155 ks observation covering an entire binary orbit. A weak Fe Kα line was detected in all orbital phases at an equivalent width (EW) of 10–20 eV. We found for the first time that its radial velocity (RV) is sinusoidally modulated by the orbital phase. The RV amplitude is 248 ± 13 km s−1, which is significantly smaller than the value (391 km s−1) expected if the emission is from the NS surface, but is consistent if the emission takes place at the O star surface. We discuss several possibilities of the line production site, including the NS surface, O star surface, O star wind, and accretion stream from the O star to the NS. We ran radiative transfer calculation for some of them assuming spherically symmetric density and velocity profiles and an isotropic distribution of X-ray emission from the NS. None of them explains the observed EW and velocity dispersion dependence on the orbital phase, suggesting that more elaborated modeling is needed. In other words, the present observational results have the capability to constrain deviations from these assumptions.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776999","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}

引用次数: 0