《天文学杂志》发表原创的天文学研究，重点是从观测中得出的重要科学成果。 AJ 中的出版物包括对数据采集、调查、分析技术、天文解释、仪器仪表以及软件和计算的描述。

The Astronomical Journal publishes original research in astronomy, focusing on significant scientific findings derived from observations. Publications in AJ include descriptions of data collection, surveys, analytical techniques, astronomical interpretations, instrumentation, as well as software and computational methods.

《Astronomical Journal》发表原创的天文学研究，重点关注从观测中得出的重要科学成果。该期刊的出版物涵盖数据采集、调查、分析技术、天文解释、仪器仪表以及软件和计算的描述。

Astronomical Journal

Abstract Ultrahot Jupiters (UHJs) possess the most extreme environments among various types of exoplanets, making them ideal laboratories to study the chemical composition and kinetics properties of exoplanet atmosphere with high-resolution spectroscopy. It has the advantage of resolving the tiny Doppler shift and weak signal from exoplanet atmosphere and has helped to detect dozens of heavy elements in UHJs including KELT-9b, WASP-76b, and WASP-121b. MASCARA-4b is a 2.8 days UHJ with an equilibrium temperature of ∼2250 K, which is expected to contain heavy elements detectable with the Very Large Telescope (VLT). In this letter, we present a survey of atoms/ions in the atmosphere of the MASCARA-4b, using the two VLT/ESPRESSO transits data. Cross-correlation analyses are performed on the obtained transmission spectra at each exposure with the template spectra generated by petitRADTRANS for atoms/ions from element Li to U. We confirm the previous detection of Mg, Ca, Cr, and Fe, and report the detection of Rb, Sm, Ti+, and Ba+ with peak signal-to-noise ratios (S/Ns) &gt; 5. We report a tentative detection of Sc+, with peak S/Ns ∼ 6 but deviating from the estimated position. The most interesting discovery is the first-time detection of elements Rb and Sm in an exoplanet. Rb is an alkaline element like Na and K, while Sm is the first lanthanide series element and is by far the heaviest one detected in exoplanets. Detailed modeling and acquiring more data are required to yield abundance ratios of the heavy elements and to understand better the common presence of them in UHJ’s atmospheres.

Zewen Jiang

Wei Wang

Gang Zhao

Meng Zhai

Yaqing Shi

Yujuan Liu

Jingkun Zhao

Yuqin Chen

The Astronomical Journal

Detection of Rubidium and Samarium in the Atmosphere of the Ultrahot Jupiter MASCARA-4b

超高温木星MASCARA-4b大气中铷和钐的探测

Abstract This study investigates the orbit determination of the Mars-crossing asteroids (MCAs) with a focus on the possibility of detecting their Yarkovsky signals. We analyze the influences of force model uncertainties on MCA orbits, including the uncertainty of the main asteroid belt, and the uncertainty of the major planets’ ephemeris. The main asteroid belt is modeled using 343 asteroids and a ring structure. The Yarkovsky effect’s quadratic nature allows it to dominate over extended observation periods. To address dynamical errors and potential interactions with the main asteroid belt, we employ not only a traditional seven-dimensional differential corrector but also a nine-dimensional differential corrector that considers radial, vertical, and transversal forces. Comparison shows that the latter approach enhances the fit to observational data. However, the reliability of the Yarkovsky parameter is not enhanced because the estimation of the radial component is physically unacceptable. Despite incorporating precise Gaia data, our analysis does not conclusively detect a Yarkovsky effect on MCAs due to uncertainties in the force model. Nevertheless, our research advances our understanding of MCA dynamics, identifying five potential candidates whose Yarkovsky effect may be observable.

Xin Liu

Xi-Yun Hou

Jun Yao

Shanhong Liu

Roberto Armellin

Qingbo Gan

Zhitao Yang

Precise Orbit Determination of Mars-crossing Asteroids

火星穿越小行星的精密轨道确定

Abstract We present 3 yr of high-contrast imaging of the PDS 70 b and c accreting protoplanets with the new extreme AO system MagAO-X as part of the MaxProtoPlanetS survey of H α protoplanets. In 2023 and 2024, our sharp (25–27 mas FWHM), well-AO-corrected (20%–26% Strehl), deep (2–3.6 hr) images detected compact ( r ∼ 30 mas; r ∼ 3 au) circumplanetary disks (CPDs) surrounding both protoplanets. Starlight scattering off the front edge of these dusty CPDs is the likely source of the bright compact continuum light detected within ∼30 mas of both planets in our simultaneously obtained continuum 668 nm filter images. After subtraction of contaminating continuum and point-spread function residuals with pyKLIP angular differential imaging and spectral differential imaging, we obtained high-contrast ASDI H α images of both planets in 2022, 2023, and 2024. We find the H α line flux of planet b fell by (8.1 ± 1.6) × 10 −16 erg s −1 cm −2 , a factor of 4.6 drop in flux from 2022 to 2023. In 2024 March, planet b continued to be faint with just a slight 1.6× rise to an H α line flux of (3.64 ± 0.87) × 10 −16 erg s −1 cm −2 . For c, we measure a significant increase of (2.74 ± 0.51) × 10 −16 erg s −1 cm −2 from 2023 to 2024, which is a factor of 2.3 increase. So both protoplanets have recently experienced significant H α variability with ∼1 yr sampling. In 2024, planet c is brighter than b: as c is brightening and b generally fading. We also tentatively detect one new point source “CC3” inside the inner disk (∼49 mas; at PA ∼ 295°; 2024) with orbital motion roughly consistent with a ∼5.6 au orbit.

Laird M. Close

Jared R. Males

Jialin 嘉霖 Li 李

Sebastiaan Y. Haffert

Joseph D. Long

Alexander D. Hedglen

Alycia J. Weinberger

Katherine B. Follette

Daniel Apai

Rene Doyon

Warren Foster

Victor Gasho

Kyle Van Gorkom

Olivier Guyon

Maggie Y. Kautz

Jay Kueny

Jennifer Lumbres

Avalon McLeod

Eden McEwen

Clarissa Pavao

Logan Pearce

Laura Perez

Lauren Schatz

Judit Szulágyi

Kevin Wagner

Ya-Lin Wu

Three Years of High-contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dust

使用MagAO-X在Hα波段对PDS 70 b和c系外行星进行三年高对比度成像：原行星Hα强变异性及行星周尘埃的证据

Abstract Ultraviolet flare emission can drive photochemistry in exoplanet atmospheres and even serve as the primary source of uncertainty in atmospheric retrievals. Additionally, flare energy budgets are not well understood due to a paucity of simultaneous observations. We present new near-UV (NUV) and optical observations of flares from three M dwarfs obtained at 20 s cadence with Swift and the Transiting Exoplanet Survey Satellite (TESS), along with a reanalysis of flares from two M dwarfs in order to explore the energy budget and timing of flares at NUV-optical wavelengths. We find a 9000 K blackbody underestimates the NUV flux by ≥2× for 54 ± 14% of flares and 14.8× for one flare. We report time lags between the bands of 0.5–6.6 minutes and develop a method to predict the qualitative flare shape and time lag to 36% ± 30% accuracy. The scatter present in optical-NUV relations is reduced by a factor of 2.0 ± 0.6 when comparing the total NUV energy with the TESS energy during the FWHM duration due to the exclusion of the T eff ≈ 5000 K tail. We show the NUV light curve can be used to remove flares from the optical light curve and consistently detect planets with 20% smaller transits than is possible without flare detrending. Finally, we demonstrate a 10× increase in the literature number of multiwavelength flares with the Early eVolution Explorer (EVE), an astrophysics Small Explorer concept to observe young clusters with simultaneous NUV and optical bands in order to detect young planets, assess their photochemical radiation environments, and observe accretion.

Ward S. Howard

Meredith A. MacGregor

Adina D. Feinstein

Laura D. Vega

Ann Marie Cody

Neal J. Turner

Valerie J. Scott

Jennifer A. Burt

Laura Venuti

Preparing for the Early eVolution Explorer: Characterizing the Photochemical Inputs and Transit Detection Efficiencies of Young Planets Using Multiwavelength Flare Observations by TESS and Swift

为早期eVolution Explorer做准备：利用TESS和Swift的多波段耀斑观测，表征年轻行星的光化学输入和凌星探测效率

Abstract Identifying and removing binary stars from stellar samples is a crucial but complicated task. Regardless of how carefully a sample is selected, some binaries will remain and complicate interpretation of results, especially via flux contamination of survey photometry. One such sample is the data from the Gaia spacecraft, which is collecting photometry and astrometry of more than 10 9 stars. To quantify the impact of binaries on Gaia photometry, we assembled a sample of known binary stars observed with adaptive optics and with accurately measured parameters, which we used to predict Gaia photometry for each stellar component. We compared the predicted photometry to the actual Gaia photometry for each system, and found that the contamination of Gaia photometry because of multiplicity decreases nonlinearly from near-complete contamination ( ρ ≤ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0</mml:mn> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> <mml:mn>15</mml:mn> </mml:math> ) to no contamination (binary projected separation, or ρ &gt; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0</mml:mn> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> <mml:mn>3</mml:mn> </mml:math> ). We provide an analytic relation to analytically correct photometric bias in a sample of Gaia stars using the binary separation. This correction is necessary because the Gaia PSF photometry extraction does not fully remove the secondary star flux for binaries with separations with ρ ≲ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0</mml:mn> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> <mml:mn>3</mml:mn> </mml:math> . We also evaluated the utility of various Gaia quality-of-fit metrics for identifying binary stars and found that Renormalized Unit Weight Error (RUWE) remains the best indicator for unresolved binaries, but multipeak image fraction probes a separation regime not currently accessible to RUWE.

Kendall Sullivan

Adam L. Kraus

Travis A. Berger

Daniel Huber

Quantifying the Contamination from nearby Stellar Companions in Gaia DR3 Photometry

量化Gaia DR3光度学中来自附近恒星伴星的污染

Abstract In the present paper, we analyze three energetic X-ray flares from the active RS CVn binary HR 1099 using data obtained from XMM-Newton. The flare duration ranges from 2.8 to 4.1 hr, with e -folding rise and decay times in the range of 27–38 minutes and 1.3–2.4 hr, respectively, indicating rapid rise and slower decay phases. The flare frequency for HR 1099 is one flare per rotation period. Time-resolved spectroscopy reveals peak flare temperatures of 39.44, 35.96, and 32.48 MK, emission measures of 7 × 10 53 –8 × 10 54 cm −3 , global abundances of 0.250, 0.299, and 0.362 Z ⊙ , and peak X-ray luminosities of 10 31.21−32.29 erg s −1 . The quiescent state is modeled with a three-temperature plasma maintained at 3.02, 6.96, and 12.53 MK. Elemental abundances during quiescent and flaring states exhibit the inverse-first ionization potential (i-FIP) effect. We have conducted a comparative analysis of coronal abundances with previous studies and found evidence supporting the i-FIP effect. The derived flare semi-loop lengths of 6–8.9 × 10 10 cm were found to be comparable to the other flares detected on HR 1099; however, they are significantly larger than typical solar flare loops. The estimated flare energies, ranging from 10 35.83−37.03 erg, classify these flares as super-flares. The magnetic field strengths of the loops are found to be in the range of 350–450 G. We diagnose the physical conditions of the flaring corona in HR 1099 through the observations of superflares and provide inference on the plasma processes.

Shweta Didel

Jeewan C. Pandey

A.K. Srivastava

Characterizing Superflares in HR 1099 Using Temporal and Spectral Analysis of XMM-Newton Observations

使用XMM-Newton观测的时间和光谱分析描述HR 1099中的超级耀斑

Abstract Future satellite missions are expected to perform all-sky surveys, thus providing the entire sky near-infrared spectral data and consequently opening a new window to investigate the evolution of galaxies. Specifically, the infrared spectral data facilitate the precise estimation of stellar masses of numerous low-redshift galaxies. We utilize the synthetic spectral energy distribution (SED) of 2853 nearby galaxies drawn from the DustPedia (435) and Stripe 82 regions (2418). The stellar mass-to-light ratio ( M * / L ) estimation accuracy over a wavelength range of 0.75−5.0 μ m is computed through the SED fitting of the multiwavelength photometric data set, which has not yet been intensively explored in previous studies. We find that the scatter in M * / L is significantly larger in the shorter and longer wavelength regimes due to the effect of the young stellar population and the dust contribution, respectively. While the scatter in M * / L approaches its minimum (∼0.10 dex) at ∼1.6 μ m, it remains sensitive to the adopted star formation history model. Furthermore, M * / L demonstrates weak and strong correlations with the stellar mass and the specific star formation rate (SFR), respectively. Upon adequately correcting the dependence of M * / L on the specific SFR, the scatter in the M * / L further reduces to 0.02 dex at ∼1.6 μ m. This indicates that the stellar mass can be estimated with an accuracy of ∼0.02 dex with a prior knowledge of SFR, which can be estimated using the infrared spectra obtained with future survey missions.

Taehyun Kim

Minjin Kim

Luis C. Ho

Yang A. Li

Woong-Seob Jeong

Dohyeong Kim

Yongjung Kim

Bomee Lee

Dongseob Lee

Jeong Hwan Lee

Jeonghyun Pyo

Hyunjin Shim

Suyeon Son

Hyunmi Song

Yujin Yang

Accuracy of Stellar Mass-to-light Ratios of Nearby Galaxies in the Near Infrared

邻近星系在近红外波段的恒星质量光度比的准确性

Abstract Photographic spectra of Plaskett’s Star (HR 2420, HD 47129, V640 Monocerotis) that were recorded at the Dominion Astrophysical Observatory have been digitized with a flatbed scanner. Many of the spectra were recorded during campaigns in 1922 and 1937, and cover wavelengths between 0.39 and 0.50 μ m. Spectra of poor quality are identified. Mean spectra near orbital phases 0.25 and 0.75 match many characteristics of synthetic spectra, although H γ and He i λ 4388 are exceptions. Evidence is presented that H γ was affected by transient activity in 1937, but not in 1922. Emission lines of N iii and He ii move with wavelength in a manner that is consistent with them tracking the motion of the secondary, indicating that an “f” spectral type designation should be assigned to the secondary. The location of the peak that is associated with the secondary in cross-correlation functions changes with time near phase 0.75, although the mean amplitude of the radial velocity curve of the secondary did not change between the two campaigns. There is also an offset in velocities of the primary measured from H γ and He i λ 4472 near phase 0.25. The velocity curves of the components suggest a mass ratio that is larger than previous estimates, although uncertainties associated with the spectroscopic features attributed to the secondary, coupled with the wavelength resolution of the spectra, complicate efforts to determine robust masses. We conclude that the peculiarities in the radial velocity curves of the components have thus been in place for over a thousand orbital cycles.

T. J. Davidge

Old Dogs, New Tricks: Re-examining Photographic Spectra of Plaskett’s Star

老狗新招：重新审视普拉斯基特星的摄影光谱

Abstract The Kepler and K2 missions enabled robust calculations of planet occurrence rates around FGKM-type stars. However, these missions observed too few stars with earlier spectral types to tightly constrain the occurrence rates of planets orbiting hotter stars. Using TESS, we calculate the occurrence rate of small (1 R ⊕ &lt; R p &lt; 8 R ⊕ ), close-in ( P orb &lt; 10 days) planets orbiting A-type stars for the first time. We search a sample of 20,257 bright (6 &lt; T &lt; 10) A-type stars for transiting planets using a custom pipeline and vet the detected signals, finding no reliable small planets. We characterize the pipeline completeness using injection–recovery tests and determine the 3 σ upper limits of the occurrence rates of close-in sub-Saturns (4 R ⊕ &lt; R p &lt; 8 R ⊕ ), sub-Neptunes (2 R ⊕ &lt; R p &lt; 4 R ⊕ ), and super-Earths (1 R ⊕ &lt; R p &lt; 2 R ⊕ ). We find upper limits of 2.2 ± 0.4 sub-Saturns and 9.1 ± 1.8 sub-Neptunes per 1000 A-type stars, which may be more than 3× and 6× lower than Kepler-era estimates for Sun-like stars. We calculate an upper limit of 186 ± 34 super-Earths per 1000 A-type stars, which may be more than 1.5× lower than that for M dwarfs. Our results hint that small, close-in planets become rarer around early-type stars and that their occurrence rates decrease faster than that of hot Jupiters with increasing host star temperature. We discuss plausible explanations for these trends, including star–disk interactions and enhanced photoevaporation of planet atmospheres.

Steven Giacalone

Courtney D. Dressing

Small and Close-in Planets are Uncommon Around A-type Stars

A型星周围的小型近距行星并不常见

Abstract We report the validation of multiple planets transiting the nearby ( d = 12.8 pc) K5V dwarf HD 101581 (GJ 435, TOI–6276, TIC 397362481). This system consists of at least two Earth-size planets whose orbits are near a mutual 4:3 mean-motion resonance, HD 101581 b ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.956</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.061</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.063</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊕</mml:mo> </mml:mrow> </mml:msub> </mml:math> , P = 4.47 days) and HD 101581c ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.990</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.070</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.070</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊕</mml:mo> </mml:mrow> </mml:msub> </mml:math> , P = 6.21 days). Both planets were discovered in Sectors 63 and 64 TESS observations and statistically validated with supporting ground-based follow-up. We also identify a signal that probably originates from a third transiting planet, TOI-6276.03 ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.982</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.098</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.114</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊕</mml:mo> </mml:mrow> </mml:msub> </mml:math> , P = 7.87 days). These planets are remarkably uniform in size and their orbits are evenly spaced, representing a prime example of the “peas-in-a-pod” architecture seen in other compact multiplanet systems. At V = 7.77, HD 101581 is the brightest star known to host multiple transiting planets smaller than 1.5 R ⊕ . HD 101581 is a promising system for atmospheric characterization and comparative planetology of small planets.

Michelle Kunimoto

Zifan Lin

Sarah Millholland

Alexander Venner

Natalie R. Hinkel

Avi Shporer

Andrew Vanderburg

Jeremy Bailey

Rafael Brahm

R. Paul Butler

Brad Carter

David R. Ciardi

Karen A. Collins

Kevin I. Collins

Knicole D. Colón

Jeffrey D. Crane

Tansu Daylan

Matías R. Díaz

John P. Doty

Fabo Feng

Eike W. Guenther

Jonathan Horner

Steve B. Howell

Jan Janik

Hugh R. A. Jones

Petr Kabáth

Shubham Kanodia

Colin Littlefield

Hugh P. Osborn

Simon O’Toole

Martin Paegert

Pavel Pintr

Richard P. Schwarz

Steve Shectman

Gregor Srdoc

Keivan G. Stassun

Johanna K. Teske

Joseph D. Twicken

Leonardo Vanzi

Sharon X. Wang

Robert A. Wittenmyer

Jon M. Jenkins

George R. Ricker

Sara Seager

Joshua Winn

Two Earth-size Planets and an Earth-size Candidate Transiting the nearby Star HD 101581*

两颗地球大小的行星及一颗地球大小的候选行星在邻近恒星HD 101581附近凌星*

Abbreviation	AJ
Journal Impact	4.93
Quartiles(Global)	ASTRONOMY & ASTROPHYSICS(Q1)

ISSN	0004-6256, 1538-3881
h-index	268

Publication Information	Publisher: American Astronomical Society，Publishing cycle: Monthly，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 1989，Proportion of original research papers: 100.00%，Self Citation Rate:23.50%， Gold OA Rate: 67.04%
Journal Fees	$4681Details
Average review cycle	网友分享经验：较快,2-4周
Average recruitment ratio	网友分享经验：较易

Astronomical Journal

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