Researchers Discover Cosmic Dust Storms from a Type Ia supernova 

Cosmic dust—like dust on Earth—comprises groupings of molecules that have condensed and stuck together in a grain. But the exact nature of dust creation in the universe has long been a mystery. Now, however, an international team of astronomers from China, the United States, Chile, the United Kingdom, Spain, etc., has made a significant discovery by identifying a previously unknown source of dust in the universe: a Type Ia supernova interacting with gas from its surroundings. 

The study was published in Nature Astronomy on Feb. 9, and was led by Prof. WANG Lingzhi from the South America Center for Astronomy of the Chinese Academy of Sciences. 

Supernovae have been known to play a role in dust formation, and to date, dust formation has only been seen in core-collapse supernovae—the explosion of massive stars. Since core-collapse supernovae do not occur in elliptical galaxies, the nature of dust creation in such galaxies has remained elusive. These galaxies are not organized into a spiral pattern like our Milky Way but are giant swarms of stars. This study shows that thermonuclear Type Ia supernovae, the explosion of white dwarf stars in binary systems with another star, may account for a significant amount of dust in these galaxies. 

The researchers monitored a supernova, SN 2018evt, for over three years using space-based facilities like NASA’s Spitzer Space Telescope and NEOWISE missions, ground-based facilities like the Las Cumbres Observatory’s global network of telescopes, and other facilities in China, South America, and Australia. They found that the supernova was running into material previously cast off by one or both stars in the binary system before the white dwarf star exploded, and the supernova sent a shock wave into this pre-existing gas. 

During more than a thousand days of monitoring the supernova, the researchers noticed that its light began to dim precipitously in the optical wavelengths that our eyes can see and then started glowing brighter in infrared light. This was a telltale sign that dust was being created in the circumstellar gas after it cooled following the supernova shock wave passing through it.

“The origins of cosmic dust have long been a mystery. This study marks the first detection of a significant and rapid dust formation process in the thermonuclear supernova interacting with circumstellar gas,” said Prof. WANG, first author as well as the corresponding author of the study. 

The study estimated that a large amount of dust must have been created by this one supernova event—an amount equal to more than 1% of the Sun’s mass. As the supernova cools, the amount of dust created should increase, perhaps tenfold. While these dust factories are not as numerous or efficient as core-collapse supernovae, there may be enough of these thermonuclear supernovae interacting with their surroundings to be a significant or even dominant source of dust in elliptical galaxies. 

“This study offers insights into the contribution of thermonuclear supernovae to cosmic dust, and more such events may be expected to be found in the era of the James Webb Space Telescope (JWST),” said Prof. WANG Lifan from Texas A&M University, a co-first author of the study. The Webb telescope sees infrared light that is perfect for the detection of dust. 

“The creation of dust is just gas getting cold enough to condense,” said Prof. Andy Howell from Las Cumbres Observatory and the University of California Santa Barbara. Howell is the Principal Investigator of the Global Supernova Project whose data was used in the study. “One day that dust will condense into planetesimals and, ultimately, planets. This is creation starting anew in the wake of stellar death. It is exciting to understand another link in the circle of life and death in the universe.”

Fig. 1, Schematic sketches of SN 2018evt at the different phases a, b, and c. The artwork at the top right presents the dust formation process.  

This paper can be accessed at

Fig. 2: Temporal evolution of the mass of the newly-formed dust in SNIa-CSM 2018evt with different compositions, together with the dust masses estimated for core-collapse supernovae.  The black line presents the power law fit to the mass of the newly formed dust of SN 2018evt for 0.3 um graphite grains.

Researchers Make Significant Progress in Characterizing Exoplanet Atmospheres Using 4-meter Ground-based Telescope

Recent Progress: Researchers Characterize Exoplanet Atmospheres Using a 4-meter Ground-based Telescope and Achieve Significant Advancements

In recent times, researchers from the National Astronomical Observatory utilized a 4-meter aperture ground-based telescope located in Chile to obtain optical wavelength transmission spectra of two hot Jupiters, namely WASP-69b and WASP-121b. Through model analysis, they were able to provide important constraints on the atmospheric properties of these planets. The research findings were published in the Monthly Notices of the Royal Astronomical Society and Astronomy and Astrophysics Research, respectively.

Hot Jupiters are a type of extreme exoplanets that orbit very close to their host stars, with orbital periods generally less than 10 days. Due to long-term and intense stellar radiation, the dayside temperature of these planets typically exceeds 1000K. As a result, their atmospheres are relatively inflated, exhibiting strong spectral signals, making them one of the most important targets for atmospheric studies. Transmission spectra are crucial data used to investigate exoplanet atmospheres. They represent the difference between the spectra during planetary transits and the out-of-transit spectra, carrying information about the temperature structure and chemical composition of the planetary atmospheres. Therefore, transmission spectra can be utilized to characterize the atmospheric properties of these planets.

WASP-69b has a radius of 1.057±0.047 RJup, a mass of 0.260±0.017 MJup, and an orbital period of approximately 3.868 days. In the transmission spectrum, the researchers, including authors Ouyang Qinglin and Wang Wei, observed a slope caused by Rayleigh scattering, inferring that the atmosphere of this planet is primarily composed of hydrogen. Additionally, the transmission spectrum of WASP-69b exhibits significant oscillation signals in the range of 700-900 nm. Combining atmospheric models, the authors suggest that this may be attributed to titanium oxide absorption. Titanium oxide is commonly considered as the main component responsible for generating temperature inversions in hot Jupiter atmospheres. However, its presence has previously only been detected in the atmospheres of ultra-hot Jupiters (Teq > 2000K), as maintaining a gaseous state for titanium oxide requires sufficiently high temperatures (> 1500K). Thus, this is the first evidence of titanium oxide’s existence in a classical hot Jupiter.

Figure 1: Transmission spectrum of WASP-69b and the corresponding best-fit inversion models. The blue and red lines represent the best-fit inversion models for optical transmission spectrum and combined optical + near-infrared transmission spectrum, respectively. The lower panels show the posterior distributions of the parameters for the two inversion models. Both inversion models exhibit relatively high metallicity.

WASP-121b has a radius of 1.865±0.065 RJup, a mass of 1.183±0.064 MJup, and an orbital period of approximately 1.275 days. The authors found that the transmission spectrum they obtained differs from previous spectra, and there are also significant differences among the spectra obtained by different researchers. Through literature research and reanalysis of previous data, they believe that these differences are likely to be real and unlikely to be attributed to data processing procedures or stellar activity. In other words, the atmospheric composition of this planet may vary over time. Inversion analysis reveals the presence of absorption signals from titanium oxide and vanadium oxide in the atmosphere of WASP-121b. However, the abundances of these components are inconsistent with previous results, further supporting the possibility of temporal variations in the atmosphere of this planet.

Figure 2: Similar to Figure 1, the transmission spectrum of WASP-121b and the corresponding best-fit inversion models are shown. The lower panels display clear posterior distributions of the inversion parameters, depicting the posterior distributions of titanium oxide and vanadium oxide abundances, corresponding to the absorption of these components in the atmosphere.

Both studies represent the first observational research on exoplanet atmospheres using the SOAR telescope. The SOAR telescope, whose full name is Southern Astrophysical Research Telescope, is operated jointly by astronomical institutions from Brazil, Chile, and the United States. The relevant observational data were obtained through the application of the lead author, Wang Wei, during their tenure at the South American Astronomical Observatory of the Chinese Academy of Sciences. The authors of the studies point out that, compared to the current mainstream large-aperture ground-based telescopes and space telescopes, 4-meter telescopes such as SOAR have slightly lower precision. However, they can still provide important constraints on the atmospheric properties of exoplanets. Therefore, 4-meter ground-based telescopes like SOAR can be a cost-effective yet reliable option for studying exoplanet atmospheres, facilitating future research on a larger sample of planetary atmospheres.

Figure 3: The SOAR telescope located in Chile, with an aperture of 4.1 meters.

Paper 1 link:

Paper 2 link:

Celebrating Chinese New Year 2024: A Fusion of Traditional Culture and Modern Astronomy in Santiago

As the Chinese New Year of the Dragon approaches in 2024, the Chinese Academy of Sciences South American Center for Astronomy (CASSACA) and the Department of Astronomy of the University of Chile (DAS, UCh) worked together to celebrate it and promote Chinese culture.

On January 26, this event was held in Santiago, Chile. Ms. Chao Zhu, from the Science and Technology Section of the Chinese Embassy in Chile; Ms. Hongjuan Gu, Chinese Director of the Confucius Institute at the Catholic University of Chile; Representatives of the Confucius Institute at the University of Santo Tomas; Prof. Francisco Martínez Concha, Dean of the Faculty of Physical and Mathematical Sciences at the University of Chile, and the Vice Dean, Prof. Marcela Munizaga; Dr. Bruno Días, President of the Astronomical Society of Chile; Prof. Guido Garay, Director of the Center for Excellence in Astrophysics and Associated Technologies (CATA); Representative of La Cisterna Municipality, and representatives of local Chinese enterprises were invited to the event. Members of Department of Astronomy of UCh, together with the CASSACA team and their families, congregated to celebrate the Chinese New Year, with a total of more than 170 participants.

The cultural experience area, highlighted by its Chinese calligraphy demonstrations and tea ceremony, garnered high praise. The lunch with authentic Chinese dishes, received an especially warm welcome, creating long lines of attendees eager to taste it. Additionally, the harmonious performances of the guzheng and erhu, along with the elegant fan dance, the mysterious face-changing, and the vigorous sword dance, received continuous applause from the audience, raising the festive atmosphere of the event to a climax and perfectly showcasing the rich flavor of the Chinese New Year. In this context, as a highlight of the event, the exhibition of Ancient Chinese Astronomy and Modern Astronomical Achievements showcased the glorious history and modern achievements of Chinese astronomy, attracting the attention of many guests, while a solar observation telescope specially set up by the Department of Astronomy of UCh also became the focus of attention of many attendees.

This celebration not only had a warm and joyful atmosphere on-site, fully showcasing the unique charm of traditional Chinese culture, but it also successfully merged traditional cultural celebrations with the exploration of modern astronomical science. As a significant bridge in the cooperation between China and Chile, CASSACA will continue to play its role as a platform, helping to boost cooperation and exchanges between both countries across multiple fields, together writing a new chapter of friendship

This event was funded by the National Astronomical Observatories of the Chinese Academy of Sciences and assisted by the Department of Astronomy of the University of Chile.

The 6th China-Chile Bilateral Conference for Astronomy Held in Chile

From November 6th to 10th, the 6th China-Chile Bilateral Conference for Astronomy was held in Puerto Varas, Chile. Over 80 experts, young scholars, and students from more than 30 astronomy research institutions, including the Chinese Academy of Sciences, various Chinese universities, and Chilean astronomy institutions, participated in the conference. They engaged in in-depth discussions on research achievements, the latest developments in China-Chile cooperation, and future collaboration opportunities. This conference was jointly organized by the National Astronomical Observatories of the Chinese Academy of Sciences (CAS, NAOC)/Chinese Academy of Sciences South America Center for Astronomy (CASSACA) and the Chilean Astronomical Society (SOCHIAS). The conference was co-chaired by Prof. Jiasheng Huang from NAOC and Prof. Diego Mardones from the University of Chile.

Gongbo Zhao, Deputy Director of NAOC and Director of CASSACA, and Bruno Días, President of SOCHIAS, delivered opening speeches and welcomed the conference attendees. The conference covered the latest research results in various research areas, including solar system objects, protoplanetary disks, star formation, interstellar medium and astrochemistry, extrasolar planets, stars and star clusters, galaxies, active galactic nuclei, and cosmology, as well as theoretical astrophysics, numerical simulations, big data astronomy, astronomical instruments and equipment, and observatory construction. The conference specially invited astronomers to present the astronomical scientific research achievements and the construction of astronomical observatories and equipment in both China and Chile under the cooperation between the two countries. The invitees included professors Licai Deng, Zhaohui Shang, and Jianrong Shi, from NAOC; professor Zhenya Zheng, from the Shanghai Astronomical Observatory, CAS; professor Ezequiel Treister, from the Pontifical Catholic University of Chile; Dr. Daniela Estefanía Olave Rojas, from the University of Talca; Dr. Richard Lane, from Bernardo O’Higgins University; Dr. Denise Riquelme, from La Serena University; and professor Bin Yang from Diego Portales University. Professor Guido Garay from the University of Chile opened the meeting by reviewing the scientific achievements and excellent talents cultivated in the past ten years of astronomical cooperation between China and Chile. Professor Junfeng Wang from Xiamen University provided a summary of the conference and offered a vision for future China-Chile astronomy cooperation.

This bilateral meeting serves to promote the exchange of astronomy between China and Chile, deepen mutual understanding and trust, expand the influence of Chinese astronomy in Chile, and lay the foundation for more effective China-Chile cooperation in the future. During the conference, astronomers from both China and Chile actively explored common ground for collaboration, fostering in-depth discussions and seeking new points of collaboration. This sets the stage for the rational and efficient utilization of research resources from both sides, focused on key research directions, and the preparation for the early production of significant scientific results in the future.

Call for the 2022 China-Chile Joint Research Fund

Based on the principles established in a 2013 Memorandum of Understanding (MoU) between the Chinese Academy of Sciences (CAS) and the National Commission of Scientific and Technological Research of the Republic of Chile (CONICYT), and the more specific guidelines described in a recent (2015) Agreement between the National Astronomical Observatories of China (NAOC), the Chinese Astronomical Society, the Chilean Astronomical Society (SOCHIAS) and CONICYT (pdf), we are now inviting research proposals that involve China-Chile collaboration in astronomical research, to promote astronomical research collaborations between China and Chile, to advance astronomy in both countries.

These funds are for research projects based on a collaboration between astronomers from China and Chile, and the subject can be in areas such as astronomical research, observations, instrumental development, theory, etc. 

The duration of each project should be two years at maximum, and can request up to 75,000 USD/year. We are aiming to support 3 or 4 projects in this call.

The deadline for applications is now extended to May,31st 2022. Inquiries can be sent to Dr. Jiasheng Huang (Chief Scientist of CASSACA;, or Dr. Lei Zhu (Deputy Director of CASSACA;

For more details, please read the attached announcement (pdf).