The Director of the Astronomical Institute of the Romanian Academy (AIRA), Dr. Mirel Bîrlan is part of the international team that used the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile, and imaged the largest objects in the asteroid belt, located between Mars and Jupiter.
Never before had such a large group of 42 asteroids been imaged so sharply. The observations reveal a wide range of peculiar shapes, from spherical to dog-bone, and are helping astronomers trace the origins of the asteroids in our Solar System.
The detailed images of these 42 objects are a leap forward in exploring asteroids, made possible thanks to ground-based telescopes, and contribute to answering the ultimate question of life, the Universe, and everything .
“Only three large main belt asteroids, Ceres, Vesta and Lutetia, have been imaged with a high level of detail so far, as they were visited by the space missions Dawn and Rosetta of NASA and the European Space Agency, respectively,” explains Pierre Vernazza, from the Laboratoire d’Astrophysique de Marseille in France, who led the asteroid study published today in Astronomy & Astrophysics.
The previously small number of detailed observations of asteroids meant that, until now, key characteristics such as their 3D shape or density had remained largely unknown.
”Between 2017 and 2019, Pierre Vernazza successfully and efficiently led an international team of which I was part and which aimed to fill this gap by conducting a thorough survey of the major bodies in the asteroid belt”, said Dr. Mirel Bîrlan, the Director of the Astronomical Institute of The Romanian Academy (AIRA).
Most of the 42 objects in their sample are larger than 100 km in size; in particular, the team imaged nearly all of the belt asteroids larger than 200 kilometres, 20 out of 23. The two biggest objects the team probed were Ceres and Vesta, which are around 940 and 520 kilometres in diameter, whereas the two smallest asteroids are Urania and Ausonia, each only about 90 kilometres.
By reconstructing the objects’ shapes, the team realised that the observed asteroids are mainly divided into two families. Some are almost perfectly spherical, such as Hygiea and Ceres, while others have a more peculiar, “elongated” shape, their undisputed queen being the asteroid Kleopatra.
By combining the asteroids’ shapes with information on their masses, the team found that the densities change significantly across the sample. The four least dense asteroids studied, including Lamberta and Sylvia, have densities of about 1.3 grams per cubic centimetre, approximately the density of coal. The highest, Psyche and Kalliope, have densities of 3.9 and 4.4 grammes per cubic centimetre, respectively, which is higher than the density of diamond (3.5 grammes per cubic centimetre).
This large difference in density suggests the asteroids’ composition varies significantly, supporting the theory that the celestial objects were formed in different areas of the Solar System and migrated to their current location.
These findings were made possible thanks to the sensitivity of the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument mounted on ESO’s VLT.
Astronomers will be able to image even more asteroids in fine detail with ESO’s upcoming Extremely Large Telescope (ELT), currently under construction in Chile and set to start operations later this decade.
”The study of asteroids is a field where Romanian researchers contribute constantly and significantly. As an associate astronomer of the Astronomical Institute of the Romanian Academy and astronomer of the Paris Observatory, I encouraged and facilitated collaborations between researchers from Romania and France. We have two Romanian doctoral students and researchers with the title of doctor who study small bodies - comets, asteroids, meteoroids - in the Solar System, "said Mirel Bîrlan.
Among the recent results of Romanian researchers are observations of the potentially dangerous asteroid (99942) Apophis, made at the Astronomical Observatory in Cluj-Napoca, Feleacu station, observations of the asteroid Pallas, observations of the asteroid (6478) Gault.
"The Institute's strategy will continue to support research efforts in these directions. Our projects include studies of asteroids approaching dangerously close to Earth, the relationships between asteroids, comets and meteors, the interaction of interplanetary matter with Earth, studies of the dynamics of natural and artificial objects near Earth, "said AIRA Director Mirel Bîrlan.
 In The Hitchhiker's Guide to the Galaxy by Douglas Adams, the number 42 is the answer to the "Ultimate Question of Life, the Universe, and Everything." Today, 12 October 2021, is the 42nd anniversary of the publication of the book.
This research was presented in a paper to appear in Astronomy & Astrophysics
Original Press release colud be find at the address: http://rosa.ro/index.php/en/news-menu/stiri/5704-meet-some-of-the-42-biggest-asteroids-in-our-solar-system
Published on Oct 13, 2021
By definition, the moment of autumn equinox in the Northern Hemisphere corresponds to the precise time when the apparent geocentric longitude of the Sun is equal to 180 degrees. But, a more common understanding of this phenomenon in our society is that it happens on a certain day of September when daytime equals the duration of nighttime. In 2021, the autumn equinox will arrive on Wednesday, 22nd of September, at 19 hours 21 minutes and 06.77 seconds UTC, respectively at 22 hours 21 minutes and 06.77 seconds (UTC+3h) which is the Current Local Time in Romania, as we use the Eastern European Summer Time (EEST). At the moment of the autumn equinox, in 2021, the geocentric latitude of the Sun equals -0.56″, the right ascension has a value of 11 hours 59 minutes and 59.985 seconds, while his declination is -0.52″. As we can see by looking at the values of geocentric latitude and right ascension, they are close to 0 and respectively to 12 hours. This is the reason why we use to say about the Sun during this moment of the autumn equinox that it is in a direction opposite to that of the vernal point. Scientifically, this statement is considered partially true and it can be generally accepted as the apparent diameter of the Sun is about 30 arcminutes. The autumn equinox in the Northern Hemisphere of the Earth corresponds to the spring equinox in the Southern Hemisphere. The calendar used nowadays in Romania is the Gregorian calendar. This time instrument was created in 1582 in order to adjust the calendar drift with respect to the succession of the seasons. Therefore, according to the Gregorian calendar, the dates of the autumn equinox will always be during 21-24 September. Actually, in most years, the autumn equinox will arrive on the 22nd or 23rd of September while the dates when this will occur on the 21st or on the 24th of September are less frequent. For example, in the year 2092, the autumn equinox will occur on the 21st of September for the first time since the creation of the Gregorian calendar. Similarly, in 1803 the autumn equinox took place on the 24th of September, for the first time since the creation of the Gregorian calendar. Image in full resolution is available here.
Published on Sep 20, 2021
A chromospheric solar image with the active region AR12860, made at Bucharest Solar Observatory on 01.01.2021. This region has the greatest activity at the beginning of the 25th solar cycle, with an M4.7 class and several C1-C9 class eruptions. Instrumentation used: Zeiss refractor 110mm F/15, Halpha Baader Solar Spectrum 0.3A, 0.4X reducer, camera ASI290MM mono. Processed in AutoStakkert 3 and gimp. In this image different features of the solar activity in the chromosphere region can be seen: sun dark spots, plages (bright regions of very hot plasma), flares, filaments of cold plasma, fibriles, prominences, and spicules at the limb. Author: scientific researcher Octavian Blagoi. Annotated colorized image in full resolution available here.
Published on Sep 03, 2021
Members of „Nicolae Bălcescu” Youth Cultural Center and a group of 18 students from several Bucharest high schools were welcomed today at the Astronomical Institute of the Romanian Academy. Their visit was joined by the B1 TV crew which made interviews and a news report. During the event, the AIRA team was represented by our Director, Dr. Mirel Bîrlan, and by historian Sorin Marin. The astronomy promoter Daniel Berteșteanu from Bucharest Astroclub, was also invited and took part in the event.
The participants had the chance to attend several science presentations as they observed the Sun through a refractory telescope using an H-alpha filter, astronomy lessons in the Planetarium Hall and didactic laboratory demonstrations with projector support and various specialized hardware and software.
All these were followed by a relaxing guided tour which included: the Ecuatorial Dome - where it is preserved the largest refractory telescope in Romania, the marvels of Meridian Hall, Bosianu House, Sun Dome, and Telescope Building. While walking towards Bosianu House, a neo-gothic architectural jewell, the students learned they were walking on the footsteps of Prince Alexander John Cuza, who was present in the same house before the 1859 Union, and who later became the first monarch of modern Romania. They have also been told about Constantin Bosianu, Doctor in Law at Sorbonne University in Paris and the owner of the house and its surrounding property for a few decades in the XIXthC., who dreamed with his mind, believed with his heart, and worked day after day for the unification of the Romanian Principalities Moldova and Walachia and the creation of modern Romania.
Published on Aug 11, 2021
Asteroidul (248370) 2005 QN173 aflat în centura principală, cu o perioadă de revoluție de 5,37 ani, are un aspect comentar. Coada a apărut în jurul datei de 7 iulie 2021, fiind descoperită pe imaginile sistemului automat ATLAS. Coada se datorează unei ciocniri sau dezintegrarii din cauza rotației prea rapide. În urma acestui eveniment, asteroidul este observat periodic de la Observatorul Astronomic de la Berthelot al Institutului Astronomic al Academiei Române. Prezentăm o imagine din data de 8 august, în care se vede scurta coadă a asteroidului (credit A. Sonka).
Published on Aug 10, 2021
The Astronomical Institute of the Romanian Academy (AIRA) took part on July 23-24, AstroFest 2021 event, organized by the Știință & Tehnică team and the SCIENCE & TECHNOLOGY Association in Crângași Park. The purpose of this event was to popularize astronomy and space sciences, through presentations accessible to the general public (experiments, demonstrations, games, etc). The Astronomical Institute participated with astronomical instruments, informative posters and other materials designed to increase the attendants interest in science. The relatively good weather allowed for astronomical observations on various objects such as the Sun, Moon, Planets and Stars. During the event, the AIRA team also engaged with the public on the topic of science instrumentation, on Q&A sessions on the stage, and provided details about the Institute's main scientific activities. (AIRA Team: Octavian Blagoi, Simon Anghel, Ruxandra Toma, Ioana Boaca)
Published on Aug 03, 2021
An annular eclipse was visible from the northern hemisphere on Jun 10, 2021. The annular eclipse happens when the Moon covers the center of the Sun leaving a small edge uncovered.
In Romania, it was visible as a partial eclipse (0.1% to 2.2%) with maximum coverage in the north-western part of the country.
The Cluj-Napoca Astronomical Observatory observed this eclipse with a maximum coverage of 0.8% starting at 13:27 and ending at 14:27.
The image shows the maximum of the eclipse as seen from Cluj (46° 45' 29.45" North and 23° 35' 17.43" East) at 13:57. The image was obtained with a Coronado SolarMax Telescope (D=60mm, F=400mm) using an Hα filter.
Sun's activity is currently increasing. There were two active regions on the Sun. In this image there is a beautiful prominence visible on the eastern limb.
Published on Jun 10, 2021
Our colleague dr. Cristina Popescu has written a chapter in a book called Star Formation Rates in Galaxies, published by Cambridge University Press. The topic dr. Cristina Popescu describes was firstly introduced by her in the field.
This book is is aimed at postgraduate students, young researchers and astrophysicists. Each chapter describes the state-of-the-art methods used to measure the intensity of recent or on-going star forming activity in galaxies and has been written by world-leading experts in the field.
"When I first received the invitation to write one of the book’s chapters, on the very topic that I first introduced to the field and then developed during my career, I was really thrilled." — UCLan's Professor of Astrophysics Cristina Popescu
Professor Popescu is President of the International Astronomical Union's Commission J1. She specialises in the investigation, formation and evolution of galaxies by studying the detailed physical processes that take place in these complex systems, related to the interaction of radiation with dust, gas and cosmic rays.
More details can be read at: UCLAN News Section
Contact: cpopescu (at) astro.ro
Published on May 28, 2021
The Section of Mathematical Sciences of the Romanian Academy announces an Open Position for the Director of the Astronomical Institute. Visit the Romanian Academy web page for more details.
Published on Mar 15, 2021
The Potentially Hazardous Asteroid (99942) Apophis was observed during the interval: 18:09:36 – 23:46:14 UTC 03/04.03.2021 at the Astronomical Observatory Cluj-Napoca, Feleacu Station. The asteroid was as a distance of only 0.1187 AU, just 2 days before the close approach to Earth due 2021.03.06. This is the last favorable opportunity for observing Apophis before its closest approach of 2029.04.13.9 at a distance of just 0.0002541 AU. An impact with Earth on 2029 is completely excluded.
The telescope used was a PlaneWave Instruments CDK 24” (D=610 mm, F/D=6.5), currently the largest Romanian telescope. The detector was a SBIG STL 6303 CCD camera (3072x2048 pixels, 9x9 micron/pixel) using VRI Johnson-Cousins filters. The exposure time for each filter was 25 sec. The movie stretches 10 R filter exposures per second (resulting in a 17 second movie for more than 5.5 hours of observations).
Astrometric and photometric data on (99942) Apophis is recorded during this close approach from Feleac and Berthelot Observatories on every clear night.
Contact: vladturcu (at) academia-cj.ro, sonka (at) astro.ro
Published on Mar 05, 2021
A spectacular fireball was detected by the Meteorite Orbits Reconstruction by Optical Imaging network (MOROI) in the morning of 3rd of March, 2021, at 05:58 local time (03:58:39 UT). The bolide flared over Suceava county for 5 seconds, reaching a maximum stellar magnitude of -11 (+/- 1). The meteor brightness matched that of the Moon, which was 85% illuminated at the time.
As seen from the city of Suceava, the object traveled from West towards East, displaying fragmentation features in the second half of the atmospheric path. Four other stations in Romania have detected the bolide. From Bacău and Bârlad, the frames during the maximum brightness were saturated, while data from Baia Mare station (250km away) allowed a proper measurement of luminosity, due to the higher extinction close to the horizon. Investigations for trajectory and orbit reconstruction are underway.
Currently, MOROI network is in the process of integration with the international FRIPON network (Fireball Recovery and InterPlanetary Observation Network). The end goal is to fill the gaps between asteroid and meteorite science, by studying the meteoroid interactions with atmosphere, and computing the location where the surviving fragments might land.contact: simon.anghel (at) astro.ro
Published on Mar 04, 2021
The first active region of the solar cycle 25 was observed on December 20, 2016. The minimum activity period between solar cycle 24 and the current cycle was approximately double compared to other similar periods.
After almost 4 years, solar cycle 25 is picking up pace!
The active region NOAA 12776 became visible on October 15 and passed the western solar limb on October 27. In the right-hand side image this region is observed by the Bucharest Observatory on October 21 when it was situated at 14° southern latitude and 45° western longitude. On October 24, a B2.3 class flare initiated from this region was recorded by GOES.
Between October 27 and November 2 another active region (NOAA 12778) was visible on the Sun and generated several C-class flares.
The solar activity as seen in the sunspot number, the number and intensity of flares, as well as other eruptive phenomena, will constantly increase over the next few years.
Today we can see two active regions on the Sun and the sunspot number is 21.
Published on Nov 05, 2020
Berthelot Observatory Survey recently reported the detection of an unusual tail of comet 246P/NEAT. The discovery, submitted to Central Bureau for Astronomical Telegrams, was published as CBET 4799. The CBET is available bellow:
Further to CBET 4793, A. Sonka, M. Birlan, and A. Nedelcu, Berthelot Observatory, Astronomical Institute of the Romanian Academy, report on the unusual shape and tail of comet 246P from CCD observations obtained with a 0.38 m f/8 reflector (39'.8 x 28' field-of-view) at Berthelot Observatory on May 12, 21, and 23. A 60-s unfiltered exposure taken on May 23 shows an obvious 3' fanlike tail in p.a. 292.8 degrees, while 46 stacked images having a total exposure time of 0.8 hr shows a long tail visible at p.a. 296.8 degrees; the tail is at least 28' long and shows a 5'.4-long discontinuity, starting at 3' from the comet's coma (after the discontinuity ends, the tail continues and possibly extends outside the field-of-view. The comet's tail is also visible in images taken on May 12 and 21 at p.a. 296.8 degrees. The discontinuity is 5' long on May 12 and 8' long on May 21. Additional unfiltered CCD total-magnitude and coma-diameter measurements for comet 246P: Mar. 20.27 UT, 15.0, 40" (H. Sato, Tokyo, Japan, 0.25-m astrograph near Mayhill, NM, USA; fan-like tail 1'.5 long toward p.a. 250-290 degrees); May 29.44, 14.6, -- (K. Kadota, Ageo, Japan, 0.25-m reflector). Visual total-magnitude and coma-diameter estimates by P. Camilleri, Katherine, NT, Australia (0.40-m reflector): June 9.47, 13.8, 1'; June 14.45, 14.0, 1'.contact: sonka (at) astro.ro
Published on Jun 19, 2020
Published on Apr 21, 2020
The Astronomical Institute and the Astronomia 21 organisation are contributing to #StayAtHome Covid19-related state.
In the frame of “Școala altfel” – “A different type of learning”, on March 31, 2020, Diana Beșliu-Ionescu has presented “The Sun and its consequences on life” to a class of fourth grade students from ”Grigorie Ghica Voievod” Gymnasium School. Using Google Meet, available on the G Suite for education, students were able to follow our researcher’s presentation.
They have learned about the Sun’s position relative to our Galaxy, its evolution and structure. The students were most impressed by the scaled difference between Sun and Earth sizes represented using a 60 cm diameter yoga ball and a very small metal marble. Students also watched high-resolution animation provided by DOT showing photospheric activity around an active region. The presentation described what is a solar cycle, which eruptive events may influence the Earth and produce geomagnetic storms. At the end students were told that their phones can show the space weather status using NASA/ESA’s Apps.
Published on Apr 13, 2020
Dr. Mirel Birlan, researcher at Paris Observatory and the Astronomical Institute of the Romanian Academy is part of a team of researchers that has looked up-close at the Pallas asteroid, the third largest object in the asteroid belt, to better understand its unusual tilted orbit. The team discovered that the surface of the asteroid is so cratered, that researchers dubbed it “the golf ball asteroid”. The research team believes that the craters are a consequence of a violent period of collision during its history and that this could also explain the unusual inclination of its orbit that has puzzled scientists for centuries.
The Pallas asteroid is almost one-seventh the size of the Moon. For centuries, astronomers have noticed that the asteroid orbits along a significantly tilted track compared with the majority of objects in the asteroid belt. This inclination remained a mystery for a long time. Now a European team, led by principal investigator Pierre Vernazza from the Laboratoire d'Astrophyisque de Marseille in France, and including Dr. Mirel Birlan, obtained images of Pallas using ESO’s Very Large Telescope (VLT), an array of four telescopes, each with an 8-meter-wide mirror, situated in the mountains of Chile.
The high resolution images show a very cratered surface of the asteroid. In addition, the researchers created a reconstructed 3D model of the shape of the asteroid, revealing a heavily cratered object on the poles, but also at the equatorial regions. The researchers identified 36 craters larger than 30 kilometres in diameter, covering more than 10% of its surface — proof that Pallas experienced a violent period of collision during its history, two to three times more intense than the one of other large asteroids like Ceres or Vesta. The heavily cratered surface explains also the preservation of its initial shape after the formation. This collisional period could also explain Pallas’ tilted orbit.
The images of the asteroid have also revealed a bright spot on the surface of Pallas. The most probable explanation of this finding and its origin is that Pallas has large deposits of salts at its surface, most probably formed by a mixture of water and silicates. The investigations carried out by the European team have also led to the discovery of the Pallas family of asteroids, a cluster of small asteroids. Simulations of impacts with Pallas suggest that this family could be the result of a violent collision about 1.7 billion years ago by an object having a diameter between 20 km and 40 km. Asteroid 3200 Phaeton, identified as the source of the Geminids meteor shower, which is observed on Earth in December, is part of the Pallas family, and could provide clues to understanding the origin of the parent body, Pallas. Thus, observing meteors and collecting meteorites coming from Phaeton could partly solve the history of Pallas.
The findings were published in Nature Astronomy https://www.nature.com/articles/s41550-019-1007-5.
Published on Feb 20, 2020
Published on Feb 14, 2020
Jean Dragesco was born on the 27th of April 1920 at Cluj. When he was only 15 years old, he was already observing the Moon through a self-made 2″ telescope. Around the same age, he read an outstanding number of astronomy books written in French and this informational pathway made him acquire new scientific knowledge, the building blocks of his future and dedicated life for science.
At 17 years old, he built another telescope, a 4″ Newtonian, which had a mirror made in Stuttgart, Germany He built another mirror, still spherical, but 6″, and finished a good Altazimuthal Newtonian telescope. At 19 years old, he became "officially" a contributor to "Mars" section of Société Astronomique de France. In the same year, Jean Dragesco founded the first organization for the young astronomers in Romania called the Astronomical Society for Young Astronomers and he became the editor of the monthly publication Urania. The next year, he founded the Microscopy Association and started to publish the Micron journal.
Jean Dragesco left Romania for France when he was 21 years old. His father, Ion Dragu, was a philosopher, writer and diplomat; he worked for the Romanian Embassy in Paris as the Head of Press Office, during that time, Eugène Ionesco was Press and Cultural Secretary within the institution. Once in France, an excellent 3″ telescope came to being out of his own hands. After he became a member of Société Astronomique de France and an active observer of "Mars" section there, he got the permission to do observations withe the 6″ and 7.5″ (152 and 190 mm) telescopes at Paris Observatory. It is also the moment when he started to collaborate with several very knowledgeable and dedicated astronomers who latter on became professionals in the field.
At 22 years old, he discovered a gap between the rings B and C of planet Saturn. However, even if the same discovery was made a few weeks later by the distinguished French astronomer Bernard Lyot, the same who invented the coronagraph, the new discovery was attributed to him and not to Dragesco and it is today known as the ''Lyot division".
Published on Jan 26, 2020
Berthelot Observatory is a remote observing station of the Astronomical Institute. Built on General Berthelot village, Hunedoara, on a protected area belonging to the Romanian Academy, the observatory is operated in remote mode from Bucharest. Following the first light in mid-November 2018, the observatory is currently involved in near-Earth objects photometric surveys and tracking and surveillance activities in the framework of EU-SST programme of the European Commission.
The telescope is a RC 14.5'' F/7 Optical Guidance System on a fast, 8°/s, equatorial mount able to track objects on medium Earth orbits. The field of view, using an SBIG STL11000M CCD camera, is of 44'x30'.
Berthelot Observatory successfully concluded the first common European exercise of space surveillance and tracking taking place from 15 to 24 July 2019. Astrometry data for the four assigned targets was provided daily in TDM format.
On December 6th, Berthelot Observatory received the code L54 from the International Astronomical Union's Minor Planet Center (MPC).
Published on Dec 06, 2019
The Institute was recently involved in two new ESA-funded research and development projects. Cheia Antenna Retrofit Phase II is a project led by RARTEL Telespazio, a Leonardo and Thales company, aiming to include the 32 meters antennas presently available at the Cheia Satellite Ground Station, in the context of European SSA programme. The Institute will assist RARTEL in all the project phases (design, software development, integration and testing) for all the aspects related to the tracking services which shall be supplied through the newly developed radar infrastructure.
SYNOPTES project, led by Romanian InSpace Engineeering startup and having both Cluj and Bucharest observatories as partners, is developing a GNSS-based real-time clock (RTC) system for the temporal synchronization of SST ground based observations. Berthelot and Feleacu astronomical stations are the testing beds and on-sky validation infrastructures of the technical solution. Contact: nedelcu (at) astro.ro)
Published on Nov 19, 2019
Bucharest Science Festival opened the gates of the Astronomical Institute of the Romanian Academy for the general public, on the 27th of September 2019. The number of visitors exceeded any estimations being around 500 adults and children.
The Planetarium Hall was permanently full of people eager to learn who participated to several presentations with PowerPoint, video or specialized software support. The academic staff and astronomy teachers were: dr. Diana Beşliu-Ionescu (AIRA), Daniel Berteşteanu (Bucharest Astroclub), Florin Zăinescu (University of Bucharest).
A special moment of the evening was the live connection with France, as dr. Mirel Bîrlan (AIRA) interacted with the public through Skype directly from Paris Astronomical Observatory.
The activities included guided tours in the museum halls of the Institute - the Meridian Hall and the Equatorial Dome. There, some of the most important and spectacular astronomical instruments of Romania are preserved for future generations and they are used today for educational purposes.The tour guides - Sorin Marin (AIRA), Octavian Blagoi (AIRA) and Marian Naiman (Bucharest Astroclub) received many questions during the whole event, especially coming from the younger friends of astronomy and they answered to all of them.
The members of Bucharest Astroclub took part in organizing the BSF 2019 event. They displayed with great openness their instruments - several telescopes and their accessories and kindly instructed the public on how to watch the planets and the stars through them.
Published on Oct 04, 2019
Using Berthelot Observatory in remote mode we imaged the first interstellar comet - C/2019 Q4 (Borisov) . Based on the current arc, the comet is on a hyperbolic orbit with an eccentricity of almost 3. The comet will reach perihelion on December 7, 2019. Berthelot Observatory will continue to monitor this objects in the following weeks. Contact: sonka (at) astro.ro.
Published on Sep 14, 2019
Romanian Astronomical Journal is an international journal covering the fields of:
Published on Aug 04, 2019
Asteroid (6478) Gault is a mysterious object; although it is in the Main Belt of asteroids, this object presents a cometary activity. During 2018 and 2019 astronomers detected a tail of matter in the asteroid's motion around the Sun, most likely due to the sublimation of light elements in its composition. The phenomenon involves the particles of dust and gas that reflect sunlight.
An international team that includes researchers from MIT-US, Astronomical Institute of the Romanian Academy, Weizmann Institute of Science in Israel, Observatoire de Paris-France, Lowell Observatory, Institute for Astronomy in Hawaii, and Northern Arizona University, has monitored the asteroid and obtained spectral and photometric data of Gault, between March and April 2019. Near-infrared spectral observations were performed in late March and early April 2019 with the 3 m diameter IRTF (NASA) telescope located in Mauna Kea-Hawaii; the spectral data were corroborated with the photometric data (Figure 1) obtained with the NEEMO-T05 telescope operated by the Astronomical Institute of the Romanian Academy.
Observational data confirm that the surface of the object contains minerals rich in silicium, most likely similar to the mineralogical composition of the asteroid family (25) Phocaea. The spectral data show variations of the spectral slope, decorrelated by a possible burst in object's cometary activity. This aspect can be explained by observing a new layer, unaltered by space weather, predominantly present on the surface of the object after the initial dust layer was entrained in the tail developed by the asteroid.
These results were recently published in the prestigious Astrophysical Journal Letters.M. Marsset, F. DeMeo, A. Sonka, et al., "Active asteroid (6478) Gault: a blue Q-type surface below the dust?” accepted in Astrophysical Journal Letters. Contacts: Adrian Sonka, Astronomical Institute of the Romanian Academy, Mirel Birlan, Paris Observatory.
Published on Aug 04, 2019
The Sun is the main driver of space weather. Space weather is determining the state of the Earth magnetosphere, which, in its turn, triggers geomagnetic storms.
Coronal mass ejections (CMEs) are pieces of the puzzle that drive space weather. They are one of the most important pieces, because of their large quantities of magnetised plasma released into the heliosphere. An Earth directed CME can hit the magnetosphere about 2-4 days after its initial detection, but not all CMEs arriving to Earth will produce a geomagnetic storm.
Numerous methods (theoretical, numerical and empirical) are being used to predict whether the CME will be geoeffective or not. In a recent paper, a team of researchers lead by D. Beșliu-Ionescu have proposed a new logistic regression model that will produce a probability, expressed as a number between 0 and 1, that a CME will be an event associated with a geomagnetic storm (Beșliu-Ionescu et al., 2019).
Published on Aug 03, 2019
Thursday, December 13, 2018, the Romanian Academy has presented the 2016 Awards. Dr. Magda Stavinschi has been granted the "Petre SERGESCU" Award for her books "Nicolae Coculescu, A Life Among Stars" and "The Astronomy and the Romanian Academy".
A novelty in the award presenting by the Romanian Academy is the initiation of the "Petre Sergescu" Award, intended for rewarding the best history of science and technology papers, award that will be given following consultations and votes from all science departments of the Romanian Academy.
The award was established 125 years after the birth of the great science historian, both for showing the importance that sciences have in the contemporary society development, and for honoring the memory of the prominent scholars with outstanding contributions, starting from the precept expressed by Auguste Comte, saying that "to understand science, it is to know its history".
Published on Dec 16, 2018