Astronomical Research Research Articles

Dark Matter Science Project

Dark Matter Science Project

Spectroscopic Devices for Asteroseismology With Small Telescopes in NARIT

National Astronomical Research Institute of Thailand (NARIT) has a manifold network of small telescopes installed worldwide. These telescopes serve educational and research purposes and are equipped mainly with CCD detectors for direct imaging and photometry. To extend the possible field of applications, several telescopes were fitted with commercially available medium resolution spectrographs eShel from Shelyak. With these devices, researchers in NARIT obtained a versatile tool for stellar spectroscopy. Here we describe the current status of available equipment, possible ways of upgrading, and briefly introduce the achieved results of the asteroseismologic study of fast-rotating stars.

International Outputs of Astronomy and Astrophysics Researchers Performed in Turkey Between 1980-2020

Bu çalışmada, astronomi ve astrofizik bilim alanında araştırmalar yürütülen "Türkiye" adresli kurumların 1980-2020 yılları arasındaki yayın performanslarının analizleri sunulmaktadır. "Türkiye" adresli araştırmacıların bilim atıf indeksi kapsamındaki dergilerde yayınladıkları, Web of Science veri tabanındaki bilimsel makaleler incelenmiştir. Analizler ışığında ülkemiz kurumlarının araştırma performanslarının yanında, ulusal ve uluslararası işbirliği eğilimleri, dergi tercihleri ve proje desteğinin rolü gibi konularda bulgular elde edilmiştir. Sonuç olarak, ilgili alanda nicelik ve nitelik açısından ulusal ve uluslararası düzeydeki analiz ve değerlendirmeler yapılarak kurum ve ülke bazlı performans göstergeleri elde edilmiştir.

Precision space telescope attitude determination and control system design principles

In order to preclude the impact of atmospheric factors on the quality of received data, state of the art astronomy research projects require spacecraft mounted telescopes. However, such designs entail the issue of sustaining the accuracy of telescope boresight attitude relative to the object of observation for the required period of time. This paper is a summary of design principles for an attitude determination and control system of a space telescope mounted rigidly onboard a spacecraft. The paper formulates requirements for attitude accuracy, and proposes a viable equipment configuration as well as a three- stage attitude control algorithm. The first stage of the algorithm ensures primary boresight pointing towards the target object prior to the object being captured in the telescope’s FoV based on star tracker and angular rate sensor data. The second stage of the algorithm ensures boresight positioning relative to the target object direction up to an error value allowing for the required image quality, based on telescope readings. The third stage of the algorithm ensures telescope boresight holding relative to the target object direction with a required accuracy for the duration of exposure. Interferences from operating satellite equipment are reviewed, and the principles of reducing their impact on sighting accuracy are formulated. Low inclination, low eccentricity geostationary orbit is recommended as the best operating environment for the space telescope’s scientific instrumentation, as well as for providing a continuous data interface between spacecraft and ground segment.

White Dwarf Photospheric Abundances in Cataclysmic Variables. IV. Deriving the [N/C] Ratio* *Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of University for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

We present results from our ongoing far-ultraviolet archival analysis of cataclysmic variable white dwarf (WD) abundances for six more systems: four SU UMa dwarf novae (BW Scl, SW UMa, BC UMa, and VW Hyi) together with the dwarf nova RX And, and the novalike DW UMa. To derive a reliable nitrogen abundance, for the four SU UMa systems (with a WD temperature T wd ∼ 14,000 to ∼22,000 K), we use the dominant N i (1492 Å) absorption line; for DW UMa (with T wd possibly as high as 60,000 K), we use the N v (∼1240 Å) doublet; and for RX And (with T wd = 33,800 K), we use the N iii (1183.0 and 1184.6 Å) absorption lines. We find a [N/C] ratio of the order of 1–100 (in solar units). Oxygen, silicon, phosphorus are mostly underabundant while aluminum is mostly overabundant. We also derive magnesium, sulfur, calcium, and iron for a few systems. VW Hyi has a solar composition secondary implying the suprasolar [N/C] ratio very likely originates in the WD itself, e.g., accretion-driven dredge-up, mixing, and convection bringing material from deeper regions to the WD surface. If the donor star in the other five systems is nonevolved, the WD is the origin for the [N/C] ratio in these systems, either directly as in VW Hyi or due to contamination of the donor and accretion disk by the repetitive explosive CNO burning during the common envelope stage of the nova explosions.

Observations of Multiphase, High-velocity, Shocked Gas in the Vela Supernova Remnant* *Based on observations made with the NASA/ESA Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer, obtained from the MAST data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Based in part on

We present an analysis of high-resolution far-UV archival spectra obtained with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope of the star HD 75309, which probes high-velocity shocked gas in the Vela supernova remnant (SNR). We examine high-velocity features from intrinsically strong absorption lines of O i, Si ii, Si ii*, C ii, C ii*, and Si iii. We also detect high-velocity components in the N v doublet and compare these features to observations of high-velocity O vi absorption, available from archival Far Ultraviolet Spectroscopic Explorer data. Kinetic temperatures are derived from the observed fractional abundances of the various ions, while gas densities and thermal pressures are obtained from the relative populations in excited fine-structure levels of C ii and Si ii. Our results indicate that the highly ionized species at high velocity probe gas in a region immediately behind a shock driven into an interstellar cloud, while the lower-ionization species trace material further downstream in the cooling region of the postshock flow. Low-velocity N v and O vi absorption may trace gas in a conductive boundary layer between the unshocked portion of the cloud and the hot X-ray-emitting intercloud medium. Temporal variations in high-velocity Ca ii absorption features observed toward HD 75309 further confirm the highly inhomogeneous nature of the interstellar medium interacting with the Vela SNR.

Die Architektur der Sternwarte auf Gut Bothkamp von 1869

Probably ›always‹ were people interested in the sky and watched the stars. The continuous progress of telescopes not only led to ever-changing uses of the stars, but also the instrument’s susceptibility to damage and bad pictures. Therefore, massive and useful locations were needed. In 1869 the Chamberlain Friedrich Gustav von Bülow – who wasn’t an astronomer himself – built on his estate’s edge in Bothkamp, Northern Germany, a private observatory, surrounded by water and open sky on a filled headland. Not only the location or it housing Europe’s biggest telescope were kind of unusual, but the observatory’s appearance and architecture. It was a rotunda with a hollow column in the middle on which the telescope stood, surrounded by eight rooms same size. The building had a gothic looking entrance, a walkable terrace with balustrade on the ground floor and a rotatable cone-type roof on the upper floor, which could be opened by an elongated flap. Bothkamp was one of just a few private observatories, which generally had little architectural design. Since it lacked the typical dome or at least a tower, it looked different anyway. Although Northern Germany had become Prussian at the time of building, the observatory’s appearance doesn’t correspond to the Berlin School at all. Additionally, there was the uncommon use as a multi-purpose building and the representative interior design. Since the astronomical research in Bothkamp ended with World War I and the building was pulled down in the 1930s, the article presents the observatory based on old views and reconstructions and classifies it within contemporary observatories and other buildings.

AstroSer: Leveraging Deep Learning for Efficient Content-based Retrieval in Massive Solar-observation Images

Rapid and proficient data retrieval is an essential component of modern astronomical research. In this paper, we address the challenge of retrieving astronomical image content by leveraging state-of-the-art deep learning techniques. We have designed a retrieval model, HybridVR, that integrates the capabilities of the deep learning models ResNet50 and VGG16 and have used it to extract key features of solar activity and solar environmental characteristics from observed images. This model enables efficient image matching and allows for content-based image retrieval (CBIR). Experimental results demonstrate that the model can achieve up to 98% similarity during CBIR while exhibiting adaptability and scalability. Our work has implications for astronomical research, data management, and education, and it can contribute to optimizing the utilization of astronomical image data. It also serves as a useful example of the application of deep learning technology in the field of astronomy.

“All manner of gymnastic evolutions” for science: Dorothea Klumpke (1861–1942) and a life in astronomical research

In this article, the extraordinary life of the astronomer Dorothea Klumpke (1861–1942) is described in detail for the first time, focussing on the four phases of her career, in which she researched various astronomical questions both as an amateur and as an employee of an observatory and as one half of a couple in science. For this reason, Klumpke's biography provides insights into the cornucopia of research approaches in astronomy at the time, in which professional and amateur astronomers explored the heavens in observatories, on field trips to exotic countries, in their own backyards, or aboard hot air balloons, using telescopes, gazing through the lenses of cameras and spectroscopes, or based on mathematical reasoning. By comparing her life to biographies of other contemporary women, including Klumpke's sisters, among them the famous neurologist Augusta Klumpke-Déjerine, the criteria that women had to fulfill in order to pursue an academic career in the long nineteenth century will be discussed at the same time. In this, particular attention will be paid to factors over which women themselves had no influence, also to show that before the middle of the twentieth century, many stars had to align in order to have such an unusual career as Dorothea Klumpke.

A Tectonic Manifesto

AbstractTectonics is the scientific discipline that studies the relationship between planetary convection and surface deformation and magmatism. In recent years global tectonic regimes and planetary evolution have become foci of astronomical and planetological research dealing in particular with potential habitability of planets orbiting other stars in our galaxy (exoplanets). This broadens the scientific impact of “tectonics” and makes it useful to outline a few guiding principles. For many, the term “tectonics” is synonymous with Plate Tectonics on Earth, but it should not be limited to only the planet we know best. Specifically, the concept should be generalized to encompass other rocky planets and moons in our Solar System and exoplanets. This article summarizes 15 general concepts about how such bodies are expected to behave.

Ancient science of weather forecasting in India with special reference to rainfall prediction

The monsoon on the Indian subcontinent remains a seasonal occurrence that all inhabitants of the subcontinent desire. Modern scientific knowledge of methods of rain forecasting has originated recently. However, traditional indigenous wisdom is peculiar to our country. In the past, India had a magnificent scientific and technical legacy. Even today, it is common that village astrologers (pandits) are right in a surprisingly high percentage of their rain predictions. Scientists and local traditional farmers have a long history of astronomical research and treatises that predict rainfall. They use different methods to forecast rainfall conditions based on numerous panchangs, almanac bio-indicators (Bhoum method), non-bio-indicators (Antariksh method), and predict the likely behavior of climate in the planting season. Rainfall forecasting also aids in the planning of operations by agriculturists, builders, water supply engineers, and others. All mortals from the subcontinent have looked at it from their own perspective, and it continues to be the subject of intense multi-dimensional engagement. The monsoon has provided a means of life for numerous civilizations while also shaping the drainages and palaeo-geography of the subcontinent. The objective of this article is to document some indigenous knowledge for forecasting climate and environmental dynamics towards community resilience.

Prophetic detection and discovery of gravitational waves

Einstein's general relativity theory includes the gravitational wave as a key prediction. One of the most crucial areas of contemporary physics is gravitational wave detection. A fantastic addition to conventional electromagnetic radiation astronomy, gravitational wave astronomy is a brand-new field of study based on the discovery of gravitational waves. In this paper, the prediction and characteristics of gravitational waves are discussed, and the detection methods of gravitational waves are given, such as the limitations of the resonant rod of gravitational waves, the working principle and basic structure of the gravitational wave probe, the laser interferometer. The gravitational wave signal of the binary black hole merger detected by the LIGO laser interferometer gravitational wave detector in the United States for the first time on September 14, 2015, which opens a new "gravitational wave window" for human astronomy research. It is foreseeable that in the near future gravitational wave research will explore the unknown information of the universe from various gravitational wave frequency bands.

Three Warm Jupiters around Solar-analog Stars Detected with TESS* *Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere under MPG programmes 0104.A-9007(A) and 0106.A-9014(A).

We report the discovery and characterization of three giant exoplanets orbiting solar-analog stars, detected by the TESS space mission and confirmed through ground-based photometry and radial velocity measurements taken at La Silla observatory with FEROS. TOI-2373 b is a warm Jupiter orbiting its host star every ∼13.3 days, and is one of the most massive known exoplanet with a precisely determined mass and radius around a star similar to the Sun, with an estimated mass of m p = and a radius of r p = . With a mean density of , TOI-2373 b is among the densest planets discovered so far. TOI-2416 b orbits its host star on a moderately eccentric orbit with a period of ∼8.3 days and an eccentricity of e = . TOI-2416 b is more massive than Jupiter with m p = , however is significantly smaller with a radius of r p = , leading to a high mean density of . TOI-2524 b is a warm Jupiter near the hot Jupiter transition region, orbiting its star every ∼7.2 days on a circular orbit. It is less massive than Jupiter with a mass of m p =, and is consistent with an inflated radius of r p =, leading to a low mean density of . The newly discovered exoplanets TOI-2373 b, TOI-2416 b, and TOI-2524 b have estimated equilibrium temperatures of K, K, and K, respectively, placing them in the sparsely populated transition zone between hot and warm Jupiters.

Investigation of an eclipsing binary star V1848 Orionis

The aim of this research is to study the variation in the orbital period and the physical parameters of the eclipsing binary system V1848 Orionis. The data for this study were observed and collected at the Thai National Observatory (TNO) and the Regional Observatory for Public, Chachoengsao (ROP-CCO) operated by the National Astronomical Research Institute of Thailand (NARIT) in the B, V, R and I bands throughout December 2022. The OC diagram shows the period variation due to the third component. The properties of the third mass were calculated as 0.23±0.02 M⊙ with an orbital radius (a3sini′) of 5.2 ± 0.3 AU and a period variation of 8.7 ± 0.2 years. Our findings indicate that the light curves show asymmetry. The analysis of V1848 Orionis' light curve using the Wilson-Devinney code revealed a mass ratio of 0.756 ± 0.007, an inclination of 76.4°±0.1°, and a 9.28 % degree of contact. Furthermore, we identified a hot spot on the primary component, associated with the O'Connell effect variation. The completeness of the multi-light curves indicates the high reliability of the determined physical parameters. The masses, radii, and luminosities of the primary and secondary components are estimated to be M1 = 0.91±0.10 M⊙, M2 = 0.69±0.07 M⊙, R1 = 0.84±0.03 R⊙, R2 = 0.74±0.03 R⊙, L1 = 0.83±0.06 L⊙, and L2 = 0.54±0.04 L⊙. The evolutionary statuses of both components in the Hertzsprung-Russell diagram show that they are either normal stars or minimally evolved stars.

Middle Permian astronomically forced upwelling in the Yangtze carbonate platform: Implications for organic matter preservation and benthic biomass

The continental shelf and slope, with upwelling systems, are usually accompanied by the formation of oxygen minimum zones, thereby stimulating marine paleoproductivity and promoting organic matter (OM) enrichment. However, due to a more oxygen-enriched environment, a distinct paleoecological characteristic, and the uncertainty of upwelling effects, it remains ambiguous whether a similar mechanism of OM preservation occurs in the adjacent carbonate platform. Here, limestone–marl alternations (LMAs) that developed in the Yangtze Carbonate Platform (YCP) during the Middle Permian were selected as the research object and compared with the chert–mudstone alternations developed on the Lower Yangtze continental shelf (LYCS). Both sets of rhythmites belong to the contemporaneous products of the Permian Chert Event in South China.Considering that the Middle Permian rhythmites in South China contain the Milankovitch record and that upwelling was controlled by astronomically forced monsoons, this study investigated the impact of upwelling on the carbonate platform by adopting astronomical cycle research. Based on GR data, a framework of astronomical cycles was established. The suboxic to anoxic conditions of the YCP are supported by evidence from syngenetic pyrite framboids, Ce/Ce* ranges, and UEF–MoEF covariation. Upwelling geochemical indicators and the detection of a pivotal (∼210-kyr) astronomical cycle regarding upwelling indicate that the YCP was affected by upwelling. The paleoproductivity/OM/fossil-related data exhibit this ∼210-kyr astronomical cycle, and the correspondence between the converted AMs determines that upwelling enhanced marine primary paleoproductivity and OM preservation. However, the intensities of short eccentricity cycles exceed those of the ∼210 kyr cycle in the time series analyses of data from the nearshore YCP. Additionally, the covariations between the upwelling proxy and total fossil content confirm the impact of upwelling on biomass of benthic organisms. Therefore, the (monsoon-driven) upwelling system in the continental shelf can extend to the carbonate platform. After reaching the platform, under the control of a (an) (astronomically forced) climatic–oceanic system, limited upwelling can stimulate primary productivity and marine OM preservation; however, upwelling reduces biomass in the bottom water. In the nearshore side of the platform, detrital dilution likely replaces upwelling as the primary stimulus for productivity. Moreover, this study reveals and explains the ∼200-kyr cycles in the Permian strata of South China for the first time.

Cryogenic Systems for Astronomical Research in the Special Astrophysical Observatory of the Russian Academy of Sciences

This article presents the main results and new plans for the development of receivers which are cooled cryogenically to deep cryogenic temperatures and used in optical and radio astronomy research at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) on both the Big Telescope Alt-Azimuthal optical telescope (BTA) and the Radio Astronomical Telescope Academy of Sciences (RATAN-600) radio telescope, 600 m in diameter. These two instruments almost completely cover the frequency range from long radio waves to the IR and optical bands (0.25–8 mm on RATAN and 10–0.3 μm, on BTA) with a certain gap in the terahertz part (8–0.01 mm) of the spectrum. Today, this range is of the greatest interest for astronomers. In particular, the ALMA (Atacama Large Millimeter Array) observatory and the worldwide network of modern telescopes called the EVH (Event Horizon Telescope) operate in this range. New developments at SAO RAS are aimed at mastering this part of the spectrum. Cryogenic systems of receivers in these ranges are a key element of the system and differ markedly from the cooling systems of optical and radio receivers that ensure cooling of the receivers to sub-Kelvin temperatures.

Image restoration with point-spread function regularization and active learning

ABSTRACT Large-scale astronomical surveys can capture numerous images of celestial objects, including galaxies and nebulae. Analysing and processing these images can reveal the intricate internal structures of these objects, allowing researchers to conduct comprehensive studies on their morphology, evolution, and physical properties. However, varying noise levels and point-spread functions can hamper the accuracy and efficiency of information extraction from these images. To mitigate these effects, we propose a novel image restoration algorithm that connects a deep-learning-based restoration algorithm with a high-fidelity telescope simulator. During the training stage, the simulator generates images with different levels of blur and noise to train the neural network based on the quality of restored images. After training, the neural network can restore images obtained by the telescope directly, as represented by the simulator. We have tested the algorithm using real and simulated observation data and have found that it effectively enhances fine structures in blurry images and increases the quality of observation images. This algorithm can be applied to large-scale sky survey data, such as data obtained by the Large Synoptic Survey Telescope (LSST), Euclid, and the Chinese Space Station Telescope (CSST), to further improve the accuracy and efficiency of information extraction, promoting advances in the field of astronomical research.

The Metallicity Variations Along the Chromosome Maps: The Globular Cluster 47 Tucanae* *Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO program 105.20NB, and on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

The “chromosome maps” (ChMs) of globular clusters (GCs) have revealed that these ancient structures are inhomogeneous in metallicity in various ways and in different natures. Type II GCs generally display larger variations, sometimes coupled with slow neutron-capture (s) element enrichments on the ChMs redder sequences, which have been interpreted as due to multiple generations of stars. On the other hand, most GCs have inhomogeneous first populations (1P) in the form of large ranges in the ΔF275W,F814W values, pointing toward a not fully mixed pristine molecular cloud. We analyze the chemical composition of GC 47 Tucanae, which shows both inhomogeneous 1P stars and, although not formally a Type II GC, hosts a small number of stars distributed on the red side of the main stream of ChM stars. Our results suggest that 1P stars are inhomogeneous in the overall metallicity, with variations on the order of ∼0.10 dex in all the chemical species. The anomalous stars distributed on a redder sequence of the ChM are further enriched in metals but have no evidence for a significant enrichment in the s elements. Our three second population stars located on the normal component of the map have metallicities similar to those of the metal-richer 1P oup, suggesting that this population formed from these stars. Although three stars is a too-small sample to draw strong conclusions, the low spread in metals of these objects might point toward formation in a fully mixed medium, possibly after a cooling flow phase.

Machine learning-based spatial data development for optimizing astronomical observatory sites in Indonesia.

Astronomical observatory construction plays an essential role in astronomy research, education, and tourism development worldwide. This study develops siting distribution scenarios for astronomical observatory locations in Indonesia using a suitability analysis by integrating the physical and atmospheric observatory suitability indexes, machine learning models, and long-term climate models. Subsequently, potential sites are equalized based on longitude and latitude zonal divisions considering air pollution disturbance risks. The study novelty comes from the integrated model development of physical and socio-economic factors, dynamic spatiotemporal analysis of atmospheric factors, and the consideration of equitable low air-pollution-disturbance-risk distribution in optimal country-level observatory construction scenarios. Generally, Indonesia comprises high suitability index and low multi-source air pollution risk areas, although some area has high astronomical suitability and high-medium air pollution risk. Most of Java, the east coast of Sumatra, and the west and south coasts of Kalimantan demonstrate "low astronomical suitability-high air pollution risk." A total of eighteen locations are recommended for new observatories, of which five, one, three, four, two, and three are on Sumatra, Java, Kalimantan, Nusa Tenggara, Sulawesi, and Papua, respectively. This study provides a comprehensive approach to determine the optimal observatory construction site to optimize the potential of astronomical activities.

Research in Dynamical Astronomy and the Quest for Planet Nine

Research in Dynamical Astronomy and the Quest for Planet Nine