Xuechao Zhang, Hongqiang Song, Xiaoqian Wang, Leping Li, Hui Fu, Rui Wang and Yao Chen
{"title":"Alpha–Proton Differential Flow of a Coronal Mass Ejection at 15 Solar Radii","authors":"Xuechao Zhang, Hongqiang Song, Xiaoqian Wang, Leping Li, Hui Fu, Rui Wang and Yao Chen","doi":"10.3847/2041-8213/ad79f2","DOIUrl":"https://doi.org/10.3847/2041-8213/ad79f2","url":null,"abstract":"Alpha–proton differential flow (Vαp) of coronal mass ejections (CMEs) and solar wind from the Sun to 1 au and beyond could influence the instantaneous correspondence of absolute abundances of alpha particles (He2+/H+) between the solar corona and interplanetary space as the abundance of a coronal source can vary with time. Previous studies based on Ulysses and Helios showed that Vαp is negligible within CMEs from 5 to 0.3 au, similar to slow solar wind (<400 km s−1). However, recent new observations using Parker Solar Probe (PSP) revealed that the Vαp of slow wind increases to ∼60 km s−1 inside 0.1 au. It is important to answer whether the Vαp of CMEs exhibits similar behavior near the Sun. In this Letter, we report the Vαp of a CME measured by PSP at ∼15 R⊙ for the first time, which demonstrates that the Vαp of CMEs is obvious and complex inside 0.1 au while keeping lower than the local Alfvén speed. A very interesting point is that the same one CME duration can be divided into A and B intervals clearly with Coulomb number below and beyond 0.5, respectively. The means of Vαp and alpha-to-proton temperature ratios of interval A (B) is 96.52 (21.96) km s−1 and 7.65 (2.23), respectively. This directly illustrates that Coulomb collisions play an important role in reducing the nonequilibrium features of CMEs. Our study indicates that the absolute elemental abundances of CMEs also might vary during their propagation.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313632","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}
Adolfo S. Carvalho, Lynne A. Hillenbrand, Kevin France and Gregory J. Herczeg
{"title":"A Far-ultraviolet-detected Accretion Shock at the Star–Disk Boundary of FU Ori","authors":"Adolfo S. Carvalho, Lynne A. Hillenbrand, Kevin France and Gregory J. Herczeg","doi":"10.3847/2041-8213/ad74eb","DOIUrl":"https://doi.org/10.3847/2041-8213/ad74eb","url":null,"abstract":"FU Ori objects are the most extreme eruptive young stars known. Their 4–5 mag photometric outbursts last for decades and are attributed to a factor of up to 10,000 increase in the stellar accretion rate. The nature of the accretion disk-to-star interface in FU Ori objects has remained a mystery for decades. To date, attempts to directly observe a shock or boundary layer have been thwarted by the apparent lack of emission in excess of the accretion disk photosphere down to λ = 2300 Å. We present a new near-ultraviolet and the first high-sensitivity far-ultraviolet (FUV) spectrum of FU Ori. The FUV continuum is detected for the first time and, at λ = 1400 Å, is more than 104 times brighter than predicted by a viscous accretion disk. We interpret the excess as arising from a shock at the boundary between the disk and the stellar surface. We model the shock emission as a blackbody and find that the temperature of the shocked material is TFUV ≈ 16,000 ± 2000 K. The shock temperature corresponds to an accretion flow along the surface of the disk that reaches a velocity of 40 km s−1 at the boundary, consistent with predictions from simulations.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313629","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}
Julie Inglis, Natasha E. Batalha, Nikole K. Lewis, Tiffany Kataria, Heather A. Knutson, Brian M. Kilpatrick, Anna Gagnebin, Sagnick Mukherjee, Maria M. Pettyjohn, Ian J. M. Crossfield, Trevor O. Foote, David Grant, Gregory W. Henry, Maura Lally, Laura K. McKemmish, David K. Sing, Hannah R. Wakeford, Juan C. Zapata Trujillo and Robert T. Zellem
{"title":"Quartz Clouds in the Dayside Atmosphere of the Quintessential Hot Jupiter HD 189733 b","authors":"Julie Inglis, Natasha E. Batalha, Nikole K. Lewis, Tiffany Kataria, Heather A. Knutson, Brian M. Kilpatrick, Anna Gagnebin, Sagnick Mukherjee, Maria M. Pettyjohn, Ian J. M. Crossfield, Trevor O. Foote, David Grant, Gregory W. Henry, Maura Lally, Laura K. McKemmish, David K. Sing, Hannah R. Wakeford, Juan C. Zapata Trujillo and Robert T. Zellem","doi":"10.3847/2041-8213/ad725e","DOIUrl":"https://doi.org/10.3847/2041-8213/ad725e","url":null,"abstract":"Recent mid-infrared observations with JWST's Mid-Infrared Instrument Low Resolution Spectrometer (MIRI LRS) have resulted in the first direct detections of absorption features from silicate clouds in the transmission spectra of two transiting exoplanets, WASP-17 b and WASP-107 b. In this Letter, we measure the mid-infrared (5–12 μm) dayside emission spectrum of the benchmark hot Jupiter HD 189733 b with MIRI LRS by combining data from two secondary-eclipse observations. We confirm the previous detection of H2O absorption at 6.5 μm from Spitzer's Infrared Spectrograph (IRS) and additionally detect H2S as well as an absorption feature at 8.7 μm in both secondary-eclipse observations. The excess absorption at 8.7 μm can be explained by the presence of small (∼0.01 μm) grains of SiO2[s] in the uppermost layers of HD 189733 b’s dayside atmosphere. This is the first direct detection of silicate clouds in HD 189733 b’s atmosphere, and the first detection of a distinct absorption feature from silicate clouds on the dayside of any hot Jupiter. We find that models including SiO2[s] are preferred by 6–7σ over clear models and those with other potential cloud species. The high-altitude location of these silicate particles is best explained by formation in the hottest regions of HD 189733 b’s dayside atmosphere near the substellar point. We additionally find that HD 189733 b’s emission spectrum longward of 9 μm displays residual features not well captured by our current atmospheric models. When combined with other JWST observations of HD 189733 b’s transmission and emission spectra at shorter wavelengths, these observations will provide us with the most detailed picture to date of the atmospheric composition and cloud properties of this benchmark hot Jupiter.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313628","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":"Quantum Statistical Effects on Warm Dark Matter and the Mass Constraint from the Cosmic Structure at Small Scales","authors":"Zhijian Zhang and Weikang Lin","doi":"10.3847/2041-8213/ad772c","DOIUrl":"https://doi.org/10.3847/2041-8213/ad772c","url":null,"abstract":"The suppression of the small-scale matter power spectrum is a distinct feature of warm dark matter (WDM), which permits a constraint on the WDM mass from galaxy surveys. In the thermal relic WDM scenario, quantum statistical effects are not manifest. In a unified framework, we investigate the quantum statistical effects for a fermion case with degenerate pressure and a boson case with Bose–Einstein condensation (BEC). Compared to the thermal relic case, the degenerate fermion case only slightly lowers the mass bound, while the boson case with a high initial BEC fraction (≳90%) significantly lowers it. On the other hand, the BEC fraction drops during the relativistic-to-nonrelativistic transition and completely disappears if the initial fraction is below ∼64%. Given the rising interest in resolving the late-time galaxy-scale problems with boson condensation, a question is posed on how a high initial BEC fraction can be dynamically created so that a dark matter condensed component remains today.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313630","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}
Cristóbal M. Espinoza, Lucien Kuiper, Wynn C. G. Ho, Danai Antonopoulou, Zaven Arzoumanian, Alice K. Harding, Paul S. Ray and George Younes
{"title":"A Growing Braking Index and Spin-down Swings for the Pulsar PSR B0540–69","authors":"Cristóbal M. Espinoza, Lucien Kuiper, Wynn C. G. Ho, Danai Antonopoulou, Zaven Arzoumanian, Alice K. Harding, Paul S. Ray and George Younes","doi":"10.3847/2041-8213/ad778c","DOIUrl":"https://doi.org/10.3847/2041-8213/ad778c","url":null,"abstract":"The way pulsars spin down is not understood in detail, but a number of possible physical mechanisms produce a spin-down rate that scales as a power of the rotation rate ( ), with the power-law index n called the braking index. PSR B0540−69 is a pulsar that in 2011, after 16 yr of spinning down with a constant braking index of 2.1, experienced a giant spin-down change and a reduction of its braking index to nearly zero. Here, we show that, following this episode, the braking index monotonically increased during a period of at least 4 yr and stabilized at ∼1.1. We also present an alternative interpretation of a more modest rotational irregularity that occurred in 2023, which was modeled as an anomalous negative step of the rotation rate. Our analysis shows that the 2023 observations can be equally well described as a transient swing of the spin-down rate (lasting ∼65 days), and the Bayesian evidence indicates that this model is strongly preferred.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313631","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}
Nathan W. Reed, Randall L. Shearer, Shawn Erin McGlynn, Boswell A. Wing, Margaret A. Tolbert and Eleanor C. Browne
{"title":"Abiotic Production of Dimethyl Sulfide, Carbonyl Sulfide, and Other Organosulfur Gases via Photochemistry: Implications for Biosignatures and Metabolic Potential","authors":"Nathan W. Reed, Randall L. Shearer, Shawn Erin McGlynn, Boswell A. Wing, Margaret A. Tolbert and Eleanor C. Browne","doi":"10.3847/2041-8213/ad74da","DOIUrl":"https://doi.org/10.3847/2041-8213/ad74da","url":null,"abstract":"Among the atmospheric gases that have been proposed as possible biosignatures in exoplanetary atmospheres, organosulfur gases are currently considered one of the more robust indicators of extant life. These gases include dimethyl sulfide (DMS; CH3SCH3), carbonyl sulfide (OCS), and carbon disulfide (CS2), which are predominantly secondary metabolic products of living organisms on Earth. Here we present results that challenge this interpretation and provide constraints on the robustness of organosulfur gases as biosignatures. Through laboratory photochemical experiments, we show the abiotic production of organosulfur gases, including DMS, OCS, methane thiol (CH3SH), ethane thiol (C2H5SH), CS2, and ethyl methyl sulfide (CH3CH2SCH3) via photochemistry in analog atmospheres. Gas-phase products of H2S/CH4/N2 haze photochemistry, with or without CO2, were collected and analyzed using gas chromatography equipped with sulfur chemiluminescence detection. Depending on the starting conditions, we estimate that DMS, OCS, CH3SH, CH3CH2SH, CS2, and CH3CH2SCH3 are produced in mixing ratios >10−1 ppmv. We further demonstrate that as the mixing ratio of CO2 increases, so does the relative importance of OCS compared to DMS. Although our results constrain the robustness of common organosulfur gases as biosignatures, the presence of these compounds may serve as an indicator of metabolic potential on exoplanets.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276824","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}
A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, J. C. Díaz-Vélez, K. Engel, T. Ergin, C. Espinoza, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. García-González, F. Garfias, H. Goksu, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernández-Cadena, I. Herzog, J. Hinton, D. Huang, F. Hueyotl-Zahuantitla, T. B. Humensky, P. Hüntemeyer, A. Iriarte, S. Kaufmann, D. Kieda, A. Lara, W. H. Lee, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, J. A. Morales-Soto, E. Moreno, M. Mostafá, M. Najafi, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papa..
{"title":"Observation of the Galactic Center PeVatron beyond 100 TeV with HAWC","authors":"A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, B. L. Dingus, M. A. DuVernois, J. C. Díaz-Vélez, K. Engel, T. Ergin, C. Espinoza, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. García-González, F. Garfias, H. Goksu, M. M. González, J. A. Goodman, S. Groetsch, J. P. Harding, S. Hernández-Cadena, I. Herzog, J. Hinton, D. Huang, F. Hueyotl-Zahuantitla, T. B. Humensky, P. Hüntemeyer, A. Iriarte, S. Kaufmann, D. Kieda, A. Lara, W. H. Lee, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, J. A. Montes, J. A. Morales-Soto, E. Moreno, M. Mostafá, M. Najafi, L. Nellen, M. Newbold, M. U. Nisa, R. Noriega-Papa..","doi":"10.3847/2041-8213/ad772e","DOIUrl":"https://doi.org/10.3847/2041-8213/ad772e","url":null,"abstract":"We report an observation of ultrahigh-energy (UHE) gamma rays from the Galactic center (GC) region, using 7 yr of data collected by the High-Altitude Water Cherenkov (HAWC) Observatory. The HAWC data are best described as a point-like source (HAWC J1746-2856) with a power-law spectrum ( ), where γ = −2.88 ± 0.15stat − 0.1sys and ϕ = 1.5 × 10−15 (TeV cm2 s)−1 extending from 6 to 114 TeV. We find no evidence of a spectral cutoff up to 100 TeV using HAWC data. Two known point-like gamma-ray sources are spatially coincident with the HAWC gamma-ray excess: Sgr A* (HESS J1745-290) and the Arc (HESS J1746-285). We subtract the known flux contribution of these point sources from the measured flux of HAWC J1746-2856 to exclude their contamination and show that the excess observed by HAWC remains significant (>5σ), with the spectrum extending to >100 TeV. Our result supports that these detected UHE gamma rays can originate via hadronic interaction of PeV cosmic-ray protons with the dense ambient gas and confirms the presence of a proton PeVatron at the GC.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142275649","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}
Shenglan Sun, Ke Wang, Xunchuan Liu and Fengwei Xu
{"title":"The Formation of Milky Way “Bones”: Ubiquitous HI Narrow Self-absorption Associated with CO Emission","authors":"Shenglan Sun, Ke Wang, Xunchuan Liu and Fengwei Xu","doi":"10.3847/2041-8213/ad77ce","DOIUrl":"https://doi.org/10.3847/2041-8213/ad77ce","url":null,"abstract":"Long and skinny molecular filaments running along Galactic spiral arms are known as “bones,” since they make up the skeleton of the Milky Way. However, their origin is still an open question. Here, we compare spectral images of HI taken by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with archival CO and Herschel dust emission to investigate the conversion from HI to H2 in two typical Galactic bones, CFG028.68-0.28 and CFG047.06+0.26. Sensitive FAST HI images and an improved methodology enabled us to extract HI narrow self-absorption (HINSA) features associated with CO line emission on and off the filaments, revealing the ubiquity of HINSA toward distant clouds for the first time. The derived cold HI abundances, [HI]/[H2], of the two bones range from ∼(0.5 to 44.7) × 10−3, which reveal different degrees of HI–H2 conversion, and are similar to those of nearby, low-mass star-forming clouds, Planck Galactic cold clumps, and a nearby active high-mass star-forming region G176.51+00.20. The HI–H2 conversion has been ongoing for 2.2–13.2 Myr in the bones, a timescale comparable to that of massive star formation therein. Therefore, we are witnessing young giant molecular clouds (GMCs) with rapid massive star formation. Our study paves the way of using HINSA to study cloud formation in Galactic bones and, more generally, in distant GMCs in the FAST era.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245615","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}
P. Romano, A. Elmhamdi, A. Marassi and and L. Contarino
{"title":"Analyzing the Sequence of Phases Leading to the Formation of the Active Region 13664, with Potential Carrington-like Characteristics","authors":"P. Romano, A. Elmhamdi, A. Marassi and and L. Contarino","doi":"10.3847/2041-8213/ad77cb","DOIUrl":"https://doi.org/10.3847/2041-8213/ad77cb","url":null,"abstract":"Several recurrent X-class flares from Active Region (AR) 13664 triggered a severe G5-class geomagnetic storm between 2024 May 10 and 11. The morphology and compactness of this AR closely resemble the AR responsible for the famous Carrington Event of 1859. Although the induced geomagnetic currents produced a value of the Dst index, probably 1 order of magnitude weaker than that of the Carrington Event, the characteristics of AR 13664 warrant special attention. Understanding the mechanisms of magnetic field emergence and transformation in the solar atmosphere that lead to the formation of such an extensive, compact, and complex AR is crucial. Our analysis of the emerging flux and horizontal motions of the magnetic structures observed in the photosphere reveals the fundamental role of a sequence of emerging bipoles at the same latitude and longitude, followed by converging and shear motions. This temporal order of processes frequently invoked in magnetohydrodynamic models—emergence, converging motions, and shear motions—is critical for the storage of magnetic energy preceding strong solar eruptions that, under the right timing, location, and direction conditions, can trigger severe space weather events on Earth.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245613","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}
Madyson G. Barber, Pa Chia Thao, Andrew W. Mann, Andrew Vanderburg, Mayuko Mori, John H. Livingston, Akihiko Fukui, Norio Narita, Adam L. Kraus, Benjamin M. Tofflemire, Elisabeth R. Newton, Joshua N. Winn, Jon M. Jenkins, Sara Seager, Karen A. Collins and Joseph D. Twicken
{"title":"TESS Investigation—Demographics of Young Exoplanets (TI-DYE). II. A Second Giant Planet in the 17 Myr System HIP 67522","authors":"Madyson G. Barber, Pa Chia Thao, Andrew W. Mann, Andrew Vanderburg, Mayuko Mori, John H. Livingston, Akihiko Fukui, Norio Narita, Adam L. Kraus, Benjamin M. Tofflemire, Elisabeth R. Newton, Joshua N. Winn, Jon M. Jenkins, Sara Seager, Karen A. Collins and Joseph D. Twicken","doi":"10.3847/2041-8213/ad77d9","DOIUrl":"https://doi.org/10.3847/2041-8213/ad77d9","url":null,"abstract":"The youngest (<50 Myr) planets are vital to understand planet formation and early evolution. The 17 Myr system HIP 67522 is already known to host a giant (≃10R⊕) planet on a tight orbit. In their discovery paper, Rizzuto et al. reported a tentative single-transit detection of an additional planet in the system using TESS. Here, we report the discovery of HIP 67522c, a 7.9 R⊕ planet that matches with that single-transit event. We confirm the signal with ground-based multiwavelength photometry from Sinistro and MuSCAT4. At a period of 14.33 days, planet c is close to a 2:1 mean-motion resonance with b (6.96 days or 2.06:1). The light curve shows distortions during many of the transits, which are consistent with spot-crossing events and/or flares. Fewer stellar activity events are seen in the transits of planet b, suggesting that planet c is crossing a more active latitude. Such distortions, combined with systematics in the TESS light-curve extraction, likely explain why planet c was previously missed.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245614","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}
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
