Pub Date : 2024-06-11DOI: 10.3847/1538-3881/ad46fb
Beverly J. Smith, Matthew Watson, M. Giroux, C. Struck
We developed an algorithm to use Galaxy Zoo 3D spiral arm masks produced by citizen scientist volunteers to semiautomatically classify spiral galaxies as either multiarmed or grand design spirals. Our final sample consists of 299 multiarmed and 245 grand design galaxies. On average, the grand design galaxies have smaller stellar masses than the multiarmed galaxies. For a given stellar mass, the grand design galaxies have larger concentrations, earlier Hubble types, smaller half-light radii, and larger central surface mass densities than the multiarmed galaxies. Lower-mass galaxies of both arm classes have later Hubble types and lower concentrations than higher-mass galaxies. In our sample, a higher fraction of grand design galaxies have classical bulges rather than pseudo-bulges, compared to multiarmed galaxies. These results are consistent with theoretical models and simulations, which suggest that dense classical bulges support the development and/or longevity of two-armed spiral patterns. Similar specific star formation rates (sSFRs) are found in multiarmed and grand design galaxies with similar stellar masses and concentrations. This implies that the sSFRs in spiral galaxies are a function of concentration and stellar mass, but independent of the number of spiral arms. Our classifications are consistent with arm counts from the Galaxy Zoo 2 project and published m = 3 Fourier amplitudes.
{"title":"Grand Design versus Multiarmed Spiral Galaxies: Dependence on Galaxy Structure","authors":"Beverly J. Smith, Matthew Watson, M. Giroux, C. Struck","doi":"10.3847/1538-3881/ad46fb","DOIUrl":"https://doi.org/10.3847/1538-3881/ad46fb","url":null,"abstract":"We developed an algorithm to use Galaxy Zoo 3D spiral arm masks produced by citizen scientist volunteers to semiautomatically classify spiral galaxies as either multiarmed or grand design spirals. Our final sample consists of 299 multiarmed and 245 grand design galaxies. On average, the grand design galaxies have smaller stellar masses than the multiarmed galaxies. For a given stellar mass, the grand design galaxies have larger concentrations, earlier Hubble types, smaller half-light radii, and larger central surface mass densities than the multiarmed galaxies. Lower-mass galaxies of both arm classes have later Hubble types and lower concentrations than higher-mass galaxies. In our sample, a higher fraction of grand design galaxies have classical bulges rather than pseudo-bulges, compared to multiarmed galaxies. These results are consistent with theoretical models and simulations, which suggest that dense classical bulges support the development and/or longevity of two-armed spiral patterns. Similar specific star formation rates (sSFRs) are found in multiarmed and grand design galaxies with similar stellar masses and concentrations. This implies that the sSFRs in spiral galaxies are a function of concentration and stellar mass, but independent of the number of spiral arms. Our classifications are consistent with arm counts from the Galaxy Zoo 2 project and published m = 3 Fourier amplitudes.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"37 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141358873","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}
Pub Date : 2024-06-10DOI: 10.3847/1538-3881/ad428d
Yan-Kun Zhang, Xi Chen, You-Xin Wang, Shijie Song, Jun-Ting Liu, Ying Lu
Concurrently with the maser flare observed in W51-North during the 3 month monitoring of H2O, NH3, and CH3OH maser variability from 2020 January to April using the Tianma 65 m Radio Telescope, we conducted Very Large Array mappings for these three maser species across the entirety of W51A region. After finding the ring-shaped H2O maser which might trace the disk surrounding the protostar residing in W51-North, the NH3 (9,6) maser delineated a jet which might be illuminated in the luminosity outburst possibly caused by the infalling streamer’s interaction with the protostar’s disk. An analysis of the comprehensive distribution of maser spots allowed us to affirm that W51N4 or ALMAmm31 serves as the primary source of the Lacy jet. Furthermore, we observed that class I methanol maser spots may extend beyond the locations of the H2O and NH3 (9,6) masers within the outflow. Additionally, emissions from other NH3 maser transitions coincided with specific 1.3 mm continuum sources. The arrangement of H2O maser spots in the vicinity of W51e2-E potentially indicates episodic accretions in this source. Combining the data from the Atacama Large Millimeter/submillimeter Array data archive for W51-North, W51e2, and W51e8, we have discovered that the H2O, NH3, and CH3OH masers, as well as the HC3N and SiO emissions are found to be good tools for tracing outflow in this work for W51A.
{"title":"Masers and Star Formation Activities in W51A","authors":"Yan-Kun Zhang, Xi Chen, You-Xin Wang, Shijie Song, Jun-Ting Liu, Ying Lu","doi":"10.3847/1538-3881/ad428d","DOIUrl":"https://doi.org/10.3847/1538-3881/ad428d","url":null,"abstract":"Concurrently with the maser flare observed in W51-North during the 3 month monitoring of H2O, NH3, and CH3OH maser variability from 2020 January to April using the Tianma 65 m Radio Telescope, we conducted Very Large Array mappings for these three maser species across the entirety of W51A region. After finding the ring-shaped H2O maser which might trace the disk surrounding the protostar residing in W51-North, the NH3 (9,6) maser delineated a jet which might be illuminated in the luminosity outburst possibly caused by the infalling streamer’s interaction with the protostar’s disk. An analysis of the comprehensive distribution of maser spots allowed us to affirm that W51N4 or ALMAmm31 serves as the primary source of the Lacy jet. Furthermore, we observed that class I methanol maser spots may extend beyond the locations of the H2O and NH3 (9,6) masers within the outflow. Additionally, emissions from other NH3 maser transitions coincided with specific 1.3 mm continuum sources. The arrangement of H2O maser spots in the vicinity of W51e2-E potentially indicates episodic accretions in this source. Combining the data from the Atacama Large Millimeter/submillimeter Array data archive for W51-North, W51e2, and W51e8, we have discovered that the H2O, NH3, and CH3OH masers, as well as the HC3N and SiO emissions are found to be good tools for tracing outflow in this work for W51A.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":" 78","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141365369","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}
Pub Date : 2024-06-05DOI: 10.3847/1538-3881/ad429f
Bihan Banerjee, M. Narang, P. Manoj, Thomas Henning, H. Tyagi, Arun Surya, P. K. Nayak, Mihir Tripathi
Giant planets exhibit diverse orbital properties, hinting at their distinct formation and dynamic histories. In this paper, using Gaia Data Release 3 (DR3), we investigate if and how the orbital properties of Jupiters are linked to their host star properties, particularly their metallicity and age. We obtain metallicities for main-sequence stars of spectral type F, G, and K, hosting hot, warm, and cold Jupiters with varying eccentricities. We compute the velocity dispersions of the host stars of these three groups using kinematic information from Gaia DR3 and obtain average ages using a velocity dispersion–age relation. We find that the host stars of hot Jupiters are relatively metal rich ([Fe/H] = 0.18 ± 0.13) and young (median age of 3.97 ± 0.51 Gyr) compared to the host stars of cold Jupiters in nearly circular orbits, which are relatively metal poor (0.03 ± 0.18) and older (median age of 6.07 ± 0.79 Gyr). The host stars of cold Jupiters in high-eccentricity orbits, on the other hand, show metallicities similar to those of the hosts of hot Jupiters, but are older, on average (median age of 6.25 ± 0.92 Gyr). The similarity in metallicity between the hosts of hot Jupiters and the hosts of cold Jupiters in high-eccentricity orbits supports high-eccentricity migration as the potential origin of hot Jupiters, with the latter serving as the progenitors of hot Jupiters. However, the average age difference between them suggests that the older hot Jupiters may have been engulfed by their host star over timescales ∼ 6 Gyr. This allows us to estimate the value of stellar tidal quality factor, Q*′∼106±1 .
{"title":"Host-star Properties of Hot, Warm, and Cold Jupiters in the Solar Neighborhood from Gaia Data Release 3: Clues to Formation Pathways","authors":"Bihan Banerjee, M. Narang, P. Manoj, Thomas Henning, H. Tyagi, Arun Surya, P. K. Nayak, Mihir Tripathi","doi":"10.3847/1538-3881/ad429f","DOIUrl":"https://doi.org/10.3847/1538-3881/ad429f","url":null,"abstract":"Giant planets exhibit diverse orbital properties, hinting at their distinct formation and dynamic histories. In this paper, using Gaia Data Release 3 (DR3), we investigate if and how the orbital properties of Jupiters are linked to their host star properties, particularly their metallicity and age. We obtain metallicities for main-sequence stars of spectral type F, G, and K, hosting hot, warm, and cold Jupiters with varying eccentricities. We compute the velocity dispersions of the host stars of these three groups using kinematic information from Gaia DR3 and obtain average ages using a velocity dispersion–age relation. We find that the host stars of hot Jupiters are relatively metal rich ([Fe/H] = 0.18 ± 0.13) and young (median age of 3.97 ± 0.51 Gyr) compared to the host stars of cold Jupiters in nearly circular orbits, which are relatively metal poor (0.03 ± 0.18) and older (median age of 6.07 ± 0.79 Gyr). The host stars of cold Jupiters in high-eccentricity orbits, on the other hand, show metallicities similar to those of the hosts of hot Jupiters, but are older, on average (median age of 6.25 ± 0.92 Gyr). The similarity in metallicity between the hosts of hot Jupiters and the hosts of cold Jupiters in high-eccentricity orbits supports high-eccentricity migration as the potential origin of hot Jupiters, with the latter serving as the progenitors of hot Jupiters. However, the average age difference between them suggests that the older hot Jupiters may have been engulfed by their host star over timescales ∼ 6 Gyr. This allows us to estimate the value of stellar tidal quality factor, Q*′∼106±1 .","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"67 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141382742","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}
Pub Date : 2024-06-05DOI: 10.3847/1538-3881/ad4149
S. Grunblatt, Nicholas Saunders, Dan Huber, D. Thorngren, S. Vissapragada, Stephanie Yoshida, K. Schlaufman, S. Giacalone, M. Macdougall, A. Chontos, E. Turtelboom, C. Beard, J. M. A. Murphy, M. Rice, H. Isaacson, R. Angus, Andrew W. Howard
Hot Neptunes, gaseous planets smaller than Saturn (∼3–8 R ⊕) with orbital periods less than 10 days, are rare. Models predict this is due to high-energy stellar irradiation stripping planetary atmospheres over time, often leaving behind only rocky planetary cores. Using our TESS full-frame-image pipeline giants in conjunction with Keck/HIRES radial velocity measurements, we present the discovery of TIC365102760 b, a 6.2 R ⊕(0.55 R J), 19.2 M ⊕(0.060 M J) planet transiting a red giant star every 4.21285 days. The old age and high equilibrium temperature yet remarkably low density of this planet ( ρp=0.58−0.20+0.30ρJ ) suggest that its gaseous envelope should have been stripped by high-energy stellar irradiation billions of years ago. The present-day planet mass and radius suggest the atmospheric stripping was slower than predicted. Unexpectedly low stellar activity and/or late-stage planet inflation could be responsible for the observed properties of this system. Further studies of this system with more precise photometry in multiple passbands will be capable of revealing more details of this planet’s atmosphere.
热海王星是小于土星（∼3-8 R ⊕）、轨道周期小于10天的气态行星，这种行星非常罕见。根据模型预测，这是由于高能恒星辐照会随着时间的推移剥离行星大气层，通常只留下岩石行星核心。利用我们的TESS全帧图像管道巨行星以及Keck/HIRES径向速度测量，我们发现了TIC365102760 b，这是一颗6.2 R ⊕(0.55 R J)、19.2 M ⊕(0.060 M J)的行星，每4.21285天穿越一颗红巨星。这颗行星的年龄较大，平衡温度较高，但密度却非常低（ρp=0.58-0.20+0.30ρJ），这表明它的气态包膜应该是在数十亿年前被高能恒星辐照剥离的。目前行星的质量和半径表明大气层的剥离比预测的要慢。意料之外的低恒星活动和/或晚期行星膨胀可能是观测到的该系统特性的原因。利用多通带更精确的光度计对该系统进行进一步研究，将能够揭示该行星大气层的更多细节。
{"title":"TESS Giants Transiting Giants. IV. A Low-density Hot Neptune Orbiting a Red Giant Star","authors":"S. Grunblatt, Nicholas Saunders, Dan Huber, D. Thorngren, S. Vissapragada, Stephanie Yoshida, K. Schlaufman, S. Giacalone, M. Macdougall, A. Chontos, E. Turtelboom, C. Beard, J. M. A. Murphy, M. Rice, H. Isaacson, R. Angus, Andrew W. Howard","doi":"10.3847/1538-3881/ad4149","DOIUrl":"https://doi.org/10.3847/1538-3881/ad4149","url":null,"abstract":"Hot Neptunes, gaseous planets smaller than Saturn (∼3–8 R ⊕) with orbital periods less than 10 days, are rare. Models predict this is due to high-energy stellar irradiation stripping planetary atmospheres over time, often leaving behind only rocky planetary cores. Using our TESS full-frame-image pipeline giants in conjunction with Keck/HIRES radial velocity measurements, we present the discovery of TIC365102760 b, a 6.2 R ⊕(0.55 R J), 19.2 M ⊕(0.060 M J) planet transiting a red giant star every 4.21285 days. The old age and high equilibrium temperature yet remarkably low density of this planet ( ρp=0.58−0.20+0.30ρJ ) suggest that its gaseous envelope should have been stripped by high-energy stellar irradiation billions of years ago. The present-day planet mass and radius suggest the atmospheric stripping was slower than predicted. Unexpectedly low stellar activity and/or late-stage planet inflation could be responsible for the observed properties of this system. Further studies of this system with more precise photometry in multiple passbands will be capable of revealing more details of this planet’s atmosphere.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"295 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141386184","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}
Pub Date : 2024-06-03DOI: 10.3847/1538-3881/ad4887
Jin-A Kim, Haeun Chung, Carlos J. Vargas, E. Hamden
We examined archival Far Ultraviolet Spectroscopic Explorer data to search for far-ultraviolet emission lines in the starburst galaxy M82. The observations were made in an outflow region that extends beyond the galactic disk. We found the O vi λ λ 1032, 1038 emission lines from the galaxy’s southern outflow region. The O vi lines suggest that the outflowing warm-hot gas is undergoing radiative cooling. We measured a radial velocity of ∼420 km s−1 from the O vi lines, which is faster than the velocity seen in Hα observations. The O vi λ1038 emission line seems to be blended with the C ii λ1037 emission line, which has a radial velocity of ∼300 km s−1, similar to what is observed in Hα observations. The outflow medium of M82 appears to be composed of gas in multiple phases with varying temperatures and kinematics. Future spectroscopic observations in high energy regimes covering a wider spatial area are necessary to understand better the properties of the warm-hot gas medium in the outflow.
我们研究了远紫外光谱探测器的档案数据，以寻找星爆星系M82中的远紫外发射线。观测是在银河系盘之外的外流区进行的。我们在星系南部的流出区发现了 O vi λ 1032、1038 发射线。O vi线表明，流出的暖热气体正在经历辐射冷却。我们从 O vi 线测出的径向速度为 ∼420 km s-1，比 Hα 观测中的速度要快。O vi λ1038 辐射线似乎与 C ii λ1037 辐射线混合在一起，后者的径向速度为 ∼300 km s-1，与 Hα 观测数据类似。M82的外流介质似乎是由温度和运动学各不相同的多相气体组成的。为了更好地了解外流中的暖热气体介质的性质，未来有必要在更大的空间范围内进行高能量的光谱观测。
{"title":"UV Cooling via O VI Emission in the Superwind of M82 Observed with the Far Ultraviolet Spectroscopic Explorer (FUSE)","authors":"Jin-A Kim, Haeun Chung, Carlos J. Vargas, E. Hamden","doi":"10.3847/1538-3881/ad4887","DOIUrl":"https://doi.org/10.3847/1538-3881/ad4887","url":null,"abstract":"We examined archival Far Ultraviolet Spectroscopic Explorer data to search for far-ultraviolet emission lines in the starburst galaxy M82. The observations were made in an outflow region that extends beyond the galactic disk. We found the O vi λ λ 1032, 1038 emission lines from the galaxy’s southern outflow region. The O vi lines suggest that the outflowing warm-hot gas is undergoing radiative cooling. We measured a radial velocity of ∼420 km s−1 from the O vi lines, which is faster than the velocity seen in Hα observations. The O vi λ1038 emission line seems to be blended with the C ii λ1037 emission line, which has a radial velocity of ∼300 km s−1, similar to what is observed in Hα observations. The outflow medium of M82 appears to be composed of gas in multiple phases with varying temperatures and kinematics. Future spectroscopic observations in high energy regimes covering a wider spatial area are necessary to understand better the properties of the warm-hot gas medium in the outflow.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"85 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141388240","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}
Pub Date : 2024-05-23DOI: 10.3847/1538-3881/ad4293
M. Jeong, Chun-Hwey Kim, K. Hong, Hye-Young Kim, Mi-Hwa Song, Jang-Ho Park, Cheongho Han
New BVR photometric and high-resolution spectroscopic observations of V505 Lac are presented with Transiting Exoplanet Survey Satellite (TESS) photometric data. The orbital period has experienced a secular decrease during the past 16 yr. A clear anticorrelation in the primary and secondary eclipse timing variation (PSETV) obtained from the TESS data is also identified. A double-lined radial velocity (RV) curve is secured, and the effective temperatures of the less- and more-massive stars (Stars 1 and 2, respectively) are measured. Using a spectral subtraction technique, excess emissions are detected in the time-series Ca ii H and K and Hα lines for Star 2. Simultaneous analysis of the light and RV curves using the Wilson–Devinney (WD) code reveals that V505 Lac is a photospherically and chromospherically active W-subtype contact binary system. The component-star masses and radii are determined to an accuracy of approximately 1%. The WD spot model is individually applied to 221 light curves segmented from the TESS data so as to derive the spot parameters of a cool spot on Star 2. The combined variations in both longitude and colatitude among the spot parameters appear to be strongly associated with those of both the anticorrelation in the PSETV and the O’Connell effect in the TESS light curves. Robust negative linear relationships between the PSETV anticorrelation size and the O’Connell effect magnitude are found for the first time. Mass–radius, mass–luminosity, and mass ratio–mass diagrams of contact binaries, along with the mass ratio frequency distribution, are presented in an attempt to elucidate the evolutionary characteristics of these systems.
结合 Transiting Exoplanet Survey Satellite（TESS）的测光数据，对 V505 Lac 进行了新的 BVR 测光和高分辨率光谱观测。从 TESS 数据中获得的主食和副食定时变化（PSETV）中也发现了明显的反相关性。确保了双线径向速度（RV）曲线，并测量了低质量恒星和高 质量恒星（分别为恒星 1 和恒星 2）的有效温度。利用光谱减法技术，在恒星 2 的时间序列 Ca ii H 和 K 及 Hα 线中检测到了过量发射。利用威尔逊-德文尼（WD）代码对光变和 RV 曲线进行的同步分析表明，V505 Lac 是一个光球和色球活动的 W 亚型接触双星系统。确定的组成恒星质量和半径精确度约为 1%。WD 光斑模型被单独应用于从 TESS 数据中分割出来的 221 条光变曲线，从而得出 2 号星上一个冷斑的光斑参数。光斑参数在经度和纬度上的综合变化似乎与 PSETV 中的反相关性和 TESS 光曲线中的奥康奈尔效应密切相关。首次发现 PSETV 反相关性大小与奥康奈尔效应大小之间存在稳健的负线性关系。研究还展示了接触双星的质量半径图、质量-光度图和质量比-质量图，以及质量比频率分布图，试图阐明这些系统的演化特征。
{"title":"Simultaneous Photometric and Spectroscopic Analysis of V505 Lacertae, a Photospherically and Chromospherically Active Contact Binary Star","authors":"M. Jeong, Chun-Hwey Kim, K. Hong, Hye-Young Kim, Mi-Hwa Song, Jang-Ho Park, Cheongho Han","doi":"10.3847/1538-3881/ad4293","DOIUrl":"https://doi.org/10.3847/1538-3881/ad4293","url":null,"abstract":"\u0000 New BVR photometric and high-resolution spectroscopic observations of V505 Lac are presented with Transiting Exoplanet Survey Satellite (TESS) photometric data. The orbital period has experienced a secular decrease during the past 16 yr. A clear anticorrelation in the primary and secondary eclipse timing variation (PSETV) obtained from the TESS data is also identified. A double-lined radial velocity (RV) curve is secured, and the effective temperatures of the less- and more-massive stars (Stars 1 and 2, respectively) are measured. Using a spectral subtraction technique, excess emissions are detected in the time-series Ca ii H and K and Hα lines for Star 2. Simultaneous analysis of the light and RV curves using the Wilson–Devinney (WD) code reveals that V505 Lac is a photospherically and chromospherically active W-subtype contact binary system. The component-star masses and radii are determined to an accuracy of approximately 1%. The WD spot model is individually applied to 221 light curves segmented from the TESS data so as to derive the spot parameters of a cool spot on Star 2. The combined variations in both longitude and colatitude among the spot parameters appear to be strongly associated with those of both the anticorrelation in the PSETV and the O’Connell effect in the TESS light curves. Robust negative linear relationships between the PSETV anticorrelation size and the O’Connell effect magnitude are found for the first time. Mass–radius, mass–luminosity, and mass ratio–mass diagrams of contact binaries, along with the mass ratio frequency distribution, are presented in an attempt to elucidate the evolutionary characteristics of these systems.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"17 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104673","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}
Pub Date : 2024-05-23DOI: 10.3847/1538-3881/ad34d9
Sarah Lange, Joseph M. Akana Murphy, N. Batalha, I. Crossfield, C. Dressing, B. Fulton, A. Howard, Dan Huber, H. Isaacson, S. R. Kane, E. Petigura, P. Robertson, L. Weiss, A. Behmard, C. Beard, S. Blunt, C. Brinkman, A. Chontos, Fei Dai, P. Dalba, T. Fetherolf, S. Giacalone, M. Hill, R. Holcomb, J. Lubin, M. MacDougall, A. Mayo, T. Močnik, D. Pidhorodetska, A. Polanski, M. Rice, L. Rosenthal, R. Rubenzahl, N. Scarsdale, E. Turtelboom, Judah Van Zandt, D. Ciardi, A. Boyle
We confirm a massive sub-Neptune-sized planet on a P = 22.8 days orbit around the star TOI-1824 (T eff = 5200 K, V = 9.7 mag). TESS first identified TOI-1824 b (formerly TOI-1824.01) as an object of interest in 2020 April after two transits in Sector 22 were matched with a single transit in Sector 21. TOI-1824 was subsequently targeted for ground-based Doppler monitoring with Keck-HIRES and APF-Levy. Using a joint model of the TESS photometry, radial velocities, and Ca ii H and K emission measurements as an activity indicator, we find that TOI-1824 b is an unusually dense sub-Neptune. The planet has a radius R p = 2.63 ± 0.15 R ⊕ and mass M p = 18.5 ± 3.2 M ⊕, implying a bulk density of 5.6 ± 1.4 g cm−3. TOI-1824 b's mass and radius situate it near a small group of “superdense sub-Neptunes” (R p ≲ 3 R ⊕ and M p ≳ 20 M ⊕). While the formation mechanism of superdense sub-Neptunes is a mystery, one possible explanation is the constructive collision of primordial icy cores; such giant impacts would drive atmospheric escape and could help explain these planets' apparent lack of massive envelopes. We discuss TOI-1824 b in the context of these overdense planets, whose unique location in the exoplanet mass–radius plane make them a potentially valuable tracer of planet formation.
我们确认了一颗海王星大小的大质量行星，其P = 22.8天的轨道围绕着TOI-1824号恒星（T eff = 5200 K，V = 9.7等）运行。TESS于2020年4月首次将TOI-1824 b（以前的TOI-1824.01）确定为关注对象，因为22扇区的两次凌日与21扇区的一次凌日相吻合。随后，TOI-1824 成为 Keck-HIRES 和 APF-Levy 的地面多普勒监测目标。利用TESS光度测量、径向速度以及Ca ii H和K发射测量的联合模型作为活动指标，我们发现TOI-1824 b是一颗异常致密的亚海王星。这颗行星的半径 R p = 2.63 ± 0.15 R ⊕，质量 M p = 18.5 ± 3.2 M ⊕，意味着体积密度为 5.6 ± 1.4 g cm-3。TOI-1824 b的质量和半径使它接近于一小群 "超密集亚海王星"（R p ≲ 3 R ⊕和M p ≳ 20 M ⊕）。虽然超密集亚海王星的形成机制是个谜，但一种可能的解释是原始冰核的建设性碰撞；这种巨大的撞击将推动大气逃逸，并有助于解释这些行星明显缺乏大质量包层的原因。我们将在这些过密行星的背景下讨论TOI-1824 b，它们在系外行星质量-半径平面上的独特位置使其成为行星形成的潜在重要示踪物。
{"title":"The TESS-Keck Survey. VII. A Superdense Sub-Neptune Orbiting TOI-1824*","authors":"Sarah Lange, Joseph M. Akana Murphy, N. Batalha, I. Crossfield, C. Dressing, B. Fulton, A. Howard, Dan Huber, H. Isaacson, S. R. Kane, E. Petigura, P. Robertson, L. Weiss, A. Behmard, C. Beard, S. Blunt, C. Brinkman, A. Chontos, Fei Dai, P. Dalba, T. Fetherolf, S. Giacalone, M. Hill, R. Holcomb, J. Lubin, M. MacDougall, A. Mayo, T. Močnik, D. Pidhorodetska, A. Polanski, M. Rice, L. Rosenthal, R. Rubenzahl, N. Scarsdale, E. Turtelboom, Judah Van Zandt, D. Ciardi, A. Boyle","doi":"10.3847/1538-3881/ad34d9","DOIUrl":"https://doi.org/10.3847/1538-3881/ad34d9","url":null,"abstract":"\u0000 We confirm a massive sub-Neptune-sized planet on a P = 22.8 days orbit around the star TOI-1824 (T\u0000 eff = 5200 K, V = 9.7 mag). TESS first identified TOI-1824 b (formerly TOI-1824.01) as an object of interest in 2020 April after two transits in Sector 22 were matched with a single transit in Sector 21. TOI-1824 was subsequently targeted for ground-based Doppler monitoring with Keck-HIRES and APF-Levy. Using a joint model of the TESS photometry, radial velocities, and Ca ii H and K emission measurements as an activity indicator, we find that TOI-1824 b is an unusually dense sub-Neptune. The planet has a radius R\u0000 p = 2.63 ± 0.15 R\u0000 ⊕ and mass M\u0000 p = 18.5 ± 3.2 M\u0000 ⊕, implying a bulk density of 5.6 ± 1.4 g cm−3. TOI-1824 b's mass and radius situate it near a small group of “superdense sub-Neptunes” (R\u0000 p ≲ 3 R\u0000 ⊕ and M\u0000 p ≳ 20 M\u0000 ⊕). While the formation mechanism of superdense sub-Neptunes is a mystery, one possible explanation is the constructive collision of primordial icy cores; such giant impacts would drive atmospheric escape and could help explain these planets' apparent lack of massive envelopes. We discuss TOI-1824 b in the context of these overdense planets, whose unique location in the exoplanet mass–radius plane make them a potentially valuable tracer of planet formation.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141105786","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}
The Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) is one of the most effective multiobject spectroscopic instruments. Its survey efficiency is guaranteed by simultaneously positioning multiple fibers via 4000 robotic fiber positioners (RFPs). With the further updates to LAMOST, the new-generation RFPs will be smaller, and the number of RFPs will increase to 5000. The RFPs are densely packed with shared working space. Thus, they may collide with each other, leading to them damaged and reducing the survey speed. In this study, we propose a new motion planning algorithm that prevents the collision of RFPs. To simplify the collision avoidance problem, we transform the motion planning process from a dynamic one into a static one by selecting one of the RFPs in each collision pair as the waiting robot. Accordingly, we design a method for choosing the waiting robot, and use a rapidly exploring random tree to plan a collision-free path for the waiting robot. However, there may be blocks between the waiting robots and their neighbors. Therefore, we also design methods to resolve these blocks. Simulations suggest that the proposed algorithm can prevent 98.4% of the collisions. About 99.9% of the positioners can reach their targets without collisions. Although developed for LAMOST, we believe that our algorithm can also be used for other instruments with equal-arm theta-phi positioners, such as the Dark Energy Spectroscopic Instrument.
{"title":"Motion Planning for the Robotic Fiber Positioners of the Large Sky Area Multiobject Fiber Spectrocopy Telescope","authors":"Feifan Zhang, Baolong Chen, Yu Wang, Zhenwan Peng, Zengxiang Zhou, Jianping Wang","doi":"10.3847/1538-3881/ad4353","DOIUrl":"https://doi.org/10.3847/1538-3881/ad4353","url":null,"abstract":"\u0000 The Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) is one of the most effective multiobject spectroscopic instruments. Its survey efficiency is guaranteed by simultaneously positioning multiple fibers via 4000 robotic fiber positioners (RFPs). With the further updates to LAMOST, the new-generation RFPs will be smaller, and the number of RFPs will increase to 5000. The RFPs are densely packed with shared working space. Thus, they may collide with each other, leading to them damaged and reducing the survey speed. In this study, we propose a new motion planning algorithm that prevents the collision of RFPs. To simplify the collision avoidance problem, we transform the motion planning process from a dynamic one into a static one by selecting one of the RFPs in each collision pair as the waiting robot. Accordingly, we design a method for choosing the waiting robot, and use a rapidly exploring random tree to plan a collision-free path for the waiting robot. However, there may be blocks between the waiting robots and their neighbors. Therefore, we also design methods to resolve these blocks. Simulations suggest that the proposed algorithm can prevent 98.4% of the collisions. About 99.9% of the positioners can reach their targets without collisions. Although developed for LAMOST, we believe that our algorithm can also be used for other instruments with equal-arm theta-phi positioners, such as the Dark Energy Spectroscopic Instrument.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":"17 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141112475","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}
Pub Date : 2024-05-07DOI: 10.3847/1538-3881/ad4150
A. R. Taylor, L. S. Legodi
We report on full-Stokes L-band observations of 98 MeerKAT calibration sources. Linear polarization is detected in 71 objects above a fractional level of 0.2%. We identify ten sources with strong fractional linear polarization and low Faraday rotation measure that could be suitable for wide-band absolute polarization calibration. We detect significant circular polarization from 24% of the sample down to a detection level of 0.07%. Circularly polarized emission is seen only for flat spectrum sources α > −0.5. We compare our polarized intensities and Faraday synthesis results to data from the NVSS at 1400 MHz and the ATCA SPASS survey at 2300 MHz. NVSS data exist for 54 of our sources and SPASS data for 20 sources. The percent polarization and rotation measures from both surveys agree well with our results. The residual instrumental linear polarization for these observations is measured at 0.16%, and the residual instrumental circular polarization is measured at 0.05%. These levels may reflect either instabilities in the relative bandpass between the two polarization channels with either time or antenna orientation, or atmospheric/ionospheric variations with pointing direction. Tracking of the hourly gain solutions on J0408-6545 after transfer of the primary gain solutions suggests a deterioration of the gain stability by a factor of several starting about 2 hr after sunrise. This suggests that observing during the nighttime could dramatically improve the precision of polarization calibration.
{"title":"A MeerKAT Polarization Survey of Southern Calibration Sources","authors":"A. R. Taylor, L. S. Legodi","doi":"10.3847/1538-3881/ad4150","DOIUrl":"https://doi.org/10.3847/1538-3881/ad4150","url":null,"abstract":"\u0000 We report on full-Stokes L-band observations of 98 MeerKAT calibration sources. Linear polarization is detected in 71 objects above a fractional level of 0.2%. We identify ten sources with strong fractional linear polarization and low Faraday rotation measure that could be suitable for wide-band absolute polarization calibration. We detect significant circular polarization from 24% of the sample down to a detection level of 0.07%. Circularly polarized emission is seen only for flat spectrum sources α > −0.5. We compare our polarized intensities and Faraday synthesis results to data from the NVSS at 1400 MHz and the ATCA SPASS survey at 2300 MHz. NVSS data exist for 54 of our sources and SPASS data for 20 sources. The percent polarization and rotation measures from both surveys agree well with our results. The residual instrumental linear polarization for these observations is measured at 0.16%, and the residual instrumental circular polarization is measured at 0.05%. These levels may reflect either instabilities in the relative bandpass between the two polarization channels with either time or antenna orientation, or atmospheric/ionospheric variations with pointing direction. Tracking of the hourly gain solutions on J0408-6545 after transfer of the primary gain solutions suggests a deterioration of the gain stability by a factor of several starting about 2 hr after sunrise. This suggests that observing during the nighttime could dramatically improve the precision of polarization calibration.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":" 33","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141129339","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}
Pub Date : 2024-05-02DOI: 10.3847/1538-3881/ad4704
A. Piatti
We present results of the analysis of a set of images obtained in the field of the Milky Way bulge globular cluster NGC 6355 using the Dark Energy Camera, which is attached to the 4 m Blanco telescope of the Cerro-Tololo Interamerican Observatory. We dealt with a heavy differential absorption across the observed field, a crowded field star population, and the superposition of field stars on to the cluster color–magnitude diagram main features to produce an intrinsic cluster stars density map. The resulting stellar density map reveals the presence of an extended envelope, a tidal tail, and scattered debris; the tidal tails pointing toward the Milky Way center. Such extra-tidal overdensities, detected above the mean star field density, resulted to be between four and six times larger that the local star field density fluctuation. They have also been recently generated by two independent studies which performed numerical simulations of synthetic tidal tails of Milky Way globular clusters. These results contrast with previous theoretical speculations about the possibility to detect tidal tails of globular clusters with chaotic orbits because they would be washed out after they were generated.
{"title":"Surviving Tidal Tails Around the Milky Way Bulge Globular Cluster NGC 6355","authors":"A. Piatti","doi":"10.3847/1538-3881/ad4704","DOIUrl":"https://doi.org/10.3847/1538-3881/ad4704","url":null,"abstract":"\u0000 We present results of the analysis of a set of images obtained in the field of the Milky Way bulge globular cluster NGC 6355 using the Dark Energy Camera, which is attached to the 4 m Blanco telescope of the Cerro-Tololo Interamerican Observatory. We dealt with a heavy differential absorption across the observed field, a crowded field star population, and the superposition of field stars on to the cluster color–magnitude diagram main features to produce an intrinsic cluster stars density map. The resulting stellar density map reveals the presence of an extended envelope, a tidal tail, and scattered debris; the tidal tails pointing toward the Milky Way center. Such extra-tidal overdensities, detected above the mean star field density, resulted to be between four and six times larger that the local star field density fluctuation. They have also been recently generated by two independent studies which performed numerical simulations of synthetic tidal tails of Milky Way globular clusters. These results contrast with previous theoretical speculations about the possibility to detect tidal tails of globular clusters with chaotic orbits because they would be washed out after they were generated.","PeriodicalId":424210,"journal":{"name":"The Astronomical Journal","volume":" 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141129877","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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