- Press Release Distribution

Astronomers make first clear detection of a moon-forming disc around an exoplanet

Astronomers make first clear detection of a moon-forming disc around an exoplanet
( Using the Atacama Large Millimetre/submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner, astronomers have unambiguously detected the presence of a disc around a planet outside our Solar System for the first time. The observations will shed new light on how moons and planets form in young stellar systems.

"Our work presents a clear detection of a disc in which satellites could be forming," says Myriam Benisty, a researcher at the University of Grenoble, France, and at the University of Chile, who led the new research published today in The Astrophysical Journal Letters. "Our ALMA observations were obtained at such exquisite resolution that we could clearly identify that the disc is associated with the planet and we are able to constrain its size for the first time," she adds.

The disc in question, called a circumplanetary disc, surrounds the exoplanet PDS 70c, one of two giant, Jupiter-like planets orbiting a star nearly 400 light-years away. Astronomers had found hints of a "moon-forming" disc around this exoplanet before but, since they could not clearly tell the disc apart from its surrounding environment, they could not confirm its detection -- until now.

In addition, with the help of ALMA, Benisty and her team found that the disc has about the same diameter as the distance from our Sun to the Earth and enough mass to form up to three satellites the size of the Moon.

But the results are not only key to finding out how moons arise. "These new observations are also extremely important to prove theories of planet formation that could not be tested until now," says Jaehan Bae, a researcher from the Earth and Planets Laboratory of the Carnegie Institution for Science, USA, and author on the study.

Planets form in dusty discs around young stars, carving out cavities as they gobble up material from this circumstellar disc to grow. In this process, a planet can acquire its own circumplanetary disc, which contributes to the growth of the planet by regulating the amount of material falling onto it. At the same time, the gas and dust in the circumplanetary disc can come together into progressively larger bodies through multiple collisions, ultimately leading to the birth of moons.

But astronomers do not yet fully understand the details of these processes. "In short, it is still unclear when, where, and how planets and moons form," explains ESO Research Fellow Stefano Facchini, also involved in the research.

"More than 4000 exoplanets have been found until now, but all of them were detected in mature systems. PDS 70b and PDS 70c, which form a system reminiscent of the Jupiter-Saturn pair, are the only two exoplanets detected so far that are still in the process of being formed," explains Miriam Keppler, researcher at the Max Planck Institute for Astronomy in Germany and one of the co-authors of the study [1].

"This system therefore offers us a unique opportunity to observe and study the processes of planet and satellite formation," Facchini adds.

PDS 70b and PDS 70c, the two planets making up the system, were first discovered using ESO's Very Large Telescope (VLT) in 2018 and 2019 respectively, and their unique nature means they have been observed with other telescopes and instruments many times since [2].

The latest high resolution ALMA observations have now allowed astronomers to gain further insights into the system. In addition to confirming the detection of the circumplanetary disc around PDS 70c and studying its size and mass, they found that PDS 70b does not show clear evidence of such a disc, indicating that it was starved of dust material from its birth environment by PDS 70c.

An even deeper understanding of the planetary system will be achieved with ESO's Extremely Large Telescope (ELT), currently under construction on Cerro Armazones in the Chilean Atacama desert. "The ELT will be key for this research since, with its much higher resolution, we will be able to map the system in great detail," says co-author Richard Teague, a researcher at the Center for Astrophysics | Harvard & Smithsonian, USA. In particular, by using the ELT's Mid-infrared ELT Imager and Spectrograph (METIS -, the team will be able to look at the gas motions surrounding PDS 70c to get a full 3D picture of the system.



[1] Despite the similarity with the Jupiter-Saturn pair, note that the disc around PDS 70c is about 500 times larger than Saturn's rings.

[2] PDS 70b was discovered using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument, while PDS 70c was found using the VLT's Multi Unit Spectroscopic Explorer (MUSE). The two-planet system has been investigated using the X-shooter instrument too, also installed on ESO's VLT.

More information

This research was presented in the paper "A Circumplanetary Disk Around PDS 70c" to appear in The Astrophysical Journal Letters.

The team is composed of Myriam Benisty (Unidad Mixta Internacional Franco-Chilena de Astronomía, CNRS, Departamento de Astronomía, Universidad de Chile, Santiago de Chile, Chile and Université Grenoble Alpes, CNRS, Grenoble, France [UGA]), Jaehan Bae (Earth and Planets Laboratory, Carnegie Institution for Science, Washington DC, USA), Stefano Facchini (European Southern Observatory, Garching bei München, Germany), Miriam Keppler (Max Planck Institute for Astronomy, Heidelberg, Germany [MPIA]), Richard Teague (Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA [CfA]), Andrea Isella (Department of Physics and Astronomy, Rice University, Houston, TX, USA), Nicolas T. Kurtovic (MPIA), Laura M. Perez (Departamento de Astronomía, Universidad de Chile, Santiago de Chile, Chile [UCHILE]), Anibal Sierra (UCHILE), Sean M. Andrews (CfA), John Carpenter (Joint ALMA Observatory, Santiago de Chile, Chile), Ian Czekala (Department of Astronomy and Astrophysics, Pennsylvania State University, PA, USA, Center for Exoplanets and Habitable Worlds, Davey Laboratory, Pennsylvania State University, PA, USA, Center for Astrostatistics, Davey Laboratory, Pennsylvania State University, PA, USA and Institute for Computational & Data Sciences, Pennsylvania State University, PA, USA), Carsten Dominik (Anton Pannekoek Institute for Astronomy, University of Amsterdam, The Netherlands), Thomas Henning (MPIA), Francois Menard (UGA), Paola Pinilla (MPIA and Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, UK) and Alice Zurlo (Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Santiago de Chile, Chile and Escuela de Ingeniería Industrial, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Santiago de Chile, Chile).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world's largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become "the world's biggest eye on the sky".

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.


* Research paper - * Photos of ALMA - * For journalists: subscribe to receive our releases under embargo in your language - * For scientists: got a story? Pitch your research -


Myriam Benisty
Universidad de Chile and Université Grenoble Alpes
Santiago de Chile, Chile

Jaehan Bae
Earth and Planets Laboratory, Carnegie Institution for Science
Washington DC, USA

Stefano Facchini
European Southern Observatory
Garching bei München, Germany

Miriam Keppler
Max Planck Institute for Astronomy
Heidelberg, Germany

Richard Teague
Center for Astrophysics | Harvard & Smithsonian
Cambridge, MA, USA

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Cell: +49 151 241 664 00

[Attachments] See images for this press release:
Astronomers make first clear detection of a moon-forming disc around an exoplanet


Spotted: An exoplanet with the potential to form moons

Spotted: An exoplanet with the potential to form moons
Cambridge, MA ¬- Astronomers at the Center for Astrophysics | Harvard & Smithsonian have helped detect the clear presence of a moon-forming region around an exoplanet -- a planet outside of our Solar System. The new observations, published Thursday in The Astrophysical Journal Letters, may shed light on how moons and planets form in young stellar systems. The detected region is known as a circumplanetary disk, a ring-shaped area surrounding a planet where moons and other satellites may form. The observed disk surrounds exoplanet PDS 70c, one of two giant, Jupiter-like planets orbiting a star nearly 400 light-years away. Astronomers had found hints of a "moon-forming" disk around this exoplanet before but since ...

Professional rugby may be associated with changes in brain structure

Participation in elite adult rugby may be associated with changes in brain structure. This is the finding of a study of 44 elite rugby players, almost half of whom had recently sustained a mild head injury while playing. The study, part of the Drake Rugby Biomarker Study, was led by Imperial College London and published in the journal Brain Communications. The research found a significant proportion of the rugby players had signs of abnormalities to the white matter, in addition to abnormal changes in white matter volume over time. White matter is the 'wiring' of the brain, and helps brain cells communicate with each other. The research team say more work is now needed to investigate the long-term effects of professional rugby on brain health. Professor David Sharp, senior author ...

COVID-19: Patients with malnutrition may be more likely to have severe outcomes

Adults and children with COVID-19 who have a history of malnutrition may have an increased likelihood of death and the need for mechanical ventilation, according to a study published in Scientific Reports. Malnutrition hampers the proper functioning of the immune system and is known to increase the risk of severe infections for other viruses, but the potential long-term effects of malnutrition on COVID-19 outcomes are less clear. Louis Ehwerhemuepha and colleagues investigated associations between malnutrition diagnoses and subsequent COVID-19 severity, using medical records for 8,604 children and 94,495 adults (older than 18 years) who were hospitalised with COVID-19 in the United States between March and June 2020. Patients with a diagnosis ...

Study shows cancer misinformation common on social media sites

Study shows cancer misinformation common on social media sites
A new study published online today in the Journal of the National Cancer Institute reports that one third of the most popular cancer treatment articles on social media contain misinformation. Further, the vast majority of that misinformation has the potential to harm cancer patients by supporting approaches that could negatively impact the quality of their treatment and chances for survival. The study also showed that articles containing misinformation garner more attention and engagement than articles with evidence-based information. The internet is a major source for health information, and misinformation is growing among many types of health conditions. This is an urgent challenge because it can result in patients making ...

Higher levels of omega-3 acids in the blood increases life expectancy by almost five years

Levels of omega-3 fatty acids in the blood are as good a predictor of mortality from any cause as smoking, according to a study involving the Hospital del Mar Medical Research Institute (IMIM), in collaboration with The Fatty Acid Research Institute in the United States and several universities in the United States and Canada. The study, published in The American Journal of Clinical Nutrition, used data from a long-term study group, the Framingham Offspring Cohort, which has been monitoring residents of this Massachusetts town, in the United States, since 1971. Researchers have found that omega-3 levels in blood erythrocytes (the so-called red blood cells) are very good mortality risk predictors. The study concludes that "Having higher levels of these ...

Antibiotics may help to treat melanoma

Some antibiotics appear to be effective against a form of skin cancer known as melanoma. Researchers at KU Leuven, Belgium, examined the effect of these antibiotics on patient-derived tumours in mice. Their findings were published in the Journal of Experimental Medicine. Researchers from KU Leuven may have found a new weapon in the fight against melanoma: antibiotics that target the 'power plants' of cancer cells. These antibiotics exploit a vulnerability that arises in tumour cells when they try to survive cancer therapy. "As the cancer evolves, some melanoma cells may escape the treatment and stop proliferating to 'hide' from ...

Mobility restrictions can have unexpected impacts on air quality

An international collaborative study led by University of Helsinki has conducted a holistic study to investigate the effects of COVID-19 restrictions on several air quality pollutants for the Po Valley region in northern Italy. The area is well known to have one of the worst air quality standards in Europe and is highly influenced by anthropogenic (human-led) activities. The study was done between research groups in Finland, Italy and Switzerland and the results were published in the journal Environmental Science: Atmospheres. Scientists have combined air quality measurements and computer simulation data over several locations in the region. The resulting studies show that reduced emissions from traffic lead to a strong reduction of nitrogen ...

Targeted removals and enhanced monitoring can help manage lionfish in the Mediterranean

Targeted removals and enhanced monitoring can help manage lionfish in the Mediterranean
Targeted removals can be effective in suppressing the number of invasive lionfish found within protected coastlines around the Mediterranean Sea. However, if they are to really be successful they need to be combined with better long-term monitoring by communities and conservationists to ensure their timing and location achieve the best results. Those are the key findings of a new study, one of the first of its kind to examine the effectiveness of targeted lionfish removals from both an ecological and a socio-economic perspective. Scientists working as part of the European Union-funded RELIONMED project ...

Pandemic changed perceptions of masked faces

Pandemic changed perceptions of masked faces
The Covid-19 pandemic has improved perceptions of facial attractiveness and healthiness of people wearing face masks in Japan. Wearing sanitary facemasks was not uncommon in Japan prior to the Covid-19 pandemic. Public health initiatives during the pandemic have led to a drastic increase in the use of facemasks as they reduce the transmission of the SARS-CoV-2 virus. The sanitary-mask effect is a model that predicted how facemasks affected perceptions of facial attractiveness. However, as mindsets might have changed due to the pandemic, it is likely that the sanitary-mask effect has been altered. A team of four scientists, including Professor Jun I. Kawahara from Hokkaido University's ...

Smokeless tobacco used more by pregnant women in South East Asia than non-pregnant women

Pregnant women in South East Asia are more likely to use smokeless tobacco than non-pregnant women, despite the added risk of foetal harm during pregnancy. The study - from the University of York - also suggests that there is no difference in smoking between pregnant women and non-pregnant women in many lower to middle income countries.(LMICs) Researchers analysed data from 42 lower to middle income countries (LMICs) and also conducted a separate sub-group analysis for the South East Asia Region. (SEAR) Researchers said the study is the first to report comparative estimates of tobacco use among pregnant and non-pregnant women from the 42 LMICs encompassing 80,454 pregnant and 1,230,262 non-pregnant women. Dr Radha ...


Scientists model 'true prevalence' of COVID-19 throughout pandemic

New breakthrough to help immune systems in the fight against cancer

Through the thin-film glass, researchers spot a new liquid phase

Administering opioids to pregnant mice alters behavior and gene expression in offspring

Brain's 'memory center' needed to recognize image sequences but not single sights

Safety of second dose of mRNA COVID-19 vaccines after first-dose allergic reactions

Changes in disparities in access to care, health after Medicare eligibility

Use of high-risk medications among lonely older adults

65+ and lonely? Don't talk to your doctor about another prescription

Exosome formulation developed to deliver antibodies for choroidal neovascularization therapy

Second COVID-19 mRNA vaccine dose found safe following allergic reactions to first dose

Plant root-associated bacteria preferentially colonize their native host-plant roots

Rare inherited variants in previously unsuspected genes may confer significant risk for autism

International experts call for a unified public health response to NAFLD and NASH epidemic

International collaboration of scientists rewrite the rulebook of flowering plant genetics

Improving air quality reduces dementia risk, multiple studies suggest

Misplaced trust: When trust in science fosters pseudoscience

Two types of blood pressure meds prevent heart events equally, but side effects differ

New statement provides path to include ethnicity, ancestry, race in genomic research

Among effective antihypertensive drugs, less popular choice is slightly safer

Juicy past of favorite Okinawan fruit revealed

Anticipate a resurgence of respiratory viruses in young children

Anxiety, depression, burnout rising as college students prepare to return to campus

Goal-setting and positive parent-child relationships reduce risk of youth vaping

New research identifies cancer types with little survival improvements in adolescents and young adul

Oncotarget: Replication-stress sensitivity in breast cancer cells

Oncotarget: TERT and its binding protein: overexpression of GABPA/B in gliomas

Development of a novel technology to check body temperature with smartphone camera

The mechanics of puncture finally explained

Extreme heat, dry summers main cause of tree death in Colorado's subalpine forests

[] Astronomers make first clear detection of a moon-forming disc around an exoplanet