Publications - Research

Spin states of asteroid members of a 4 Gyr-old collisional family.

D. Athanasopoulos, J. Hanuš, P. Antonini, M. Audejean, C. Avdellidou, R. Behrend, L. Bernasconi, R. Bonamico, J.W. Brinsfield, S. Brouillard, L. Brunetto, M. Conjat, M. Delbo, M. Fauvaud, S. Fauvaud, A. Ferrero, K. Gazeas, R. Gonz\'alez, D. Higgins, G. Kobber, R.A. Koff, A. Kryszczynska, F. Livet, A. Marciniak, J. Oey, O. Pejcha, J.J. Rives, J.P. Rivet, R. Roy, N. Sioulas, G. van Belle K. Tsiganis



Reference: D. Athanasopoulos, J. Hanuš, et al., 2022, A&A (TBD)

Determining the rotational period of Main-Belt asteroid 282 Chlorinde

R. Bonamico, G. Van Belle


Based on CCD photometric observations of the main-belt asteroid 282 Chlorinde, we report the results of the light curve analysis P=49.533 h, A=0.26 mag.

Reference: R. Bonamico and G. Van Belle, 2021, MPBu, 48, 210

Ancient Asteroids: An international observing campaign for the characterisation of the oldest asteroid collisional families

D. Athanasopoulos, R. Bonamico, G. Van Belle, M. Conjat, A. Ferrero, J. Hanuš, J. Ďurech, C. Avdellidiou, K. Tsiganis, M. Delbo, and K. Gazeas


We invite observers to join an international observing campaign and obtain light curve of a selected number of the most ancient asteroids. Analysis of these data will be important to reconstruct the original state of the asteroid belt, which is a crucial problem of planetary science. This original state can be reconstructed through the identification of the oldest asteroid families. Traditional identification methods, like Hierarchical Clustering Methods (Zappala et al., 1990; HCM), have difficulties to recognise Gyr- and older asteroid families, whose members are very dispersed by the Yarkovsky effect. An innovative method, called V-shape search (Bolin et al., 2017), has been demonstrated effective (Deienno et al. 2021) to identify these aforementioned very old collisional families by searching for the signature of the size dependent dispersion of family members operated by the Yarkovsky effect. The method has already successfully identified two primordial families which likely formed before the giant planet orbital instability (Tsiganis et al., 2005) and could be as old as the Solar System and an ancient one that is ~3 Gyr-old (Delbo et al., 2017; 2019). There is evidence from observations and theoretical evolution models that there are more old families to be detected (Delbo et al., 2017; Dermott et al., 2018). However, the reliability of these V-shape families should be independently verified. A very important test of family membership is the anisotropic distribution of spin vectors of the asteroid family member, which is a fingerprint of the Yarkovsky effect evolution (Hanus et al. 2013). Namely, to test the working hypothesis that according to theories of asteroid orbital evolution under the Yarkovsky effect, members of the inward (outward) side of V-shape of a family have a statistical predominance of retrograde (prograde) objects. This hypothesis has been tested (Hanus, et al., 2013) already for known families, and it is a reliable test for family membership.

Reference: D. Athanasopoulos, R. Bonamico, G. Van Belle, M. Conjat, A. Ferrero, J. Hanuš, J. Ďurech, C. Avdellidiou, K. Tsiganis, M. Delbo, and K. Gazeas, 2021, EPSC, 15, 355

Preliminary results on the photometric study of two primordial family asteroids

D. Athanasopoulos, K. Gazeas, M. Delbo


The so-called "primordial family", is a recently discovered collisional family that could be as old as the Solar system. It contains low-albedo asteroids and is located in the inner Main Belt. This family was identified by the V-shape technique and is estimated to be at least 4 Gyr old, meaning that occurred before the giant planet instability. Asteroids 2768 Gorky (1972 RX3) and 9086 (1995 SA3) are members of the primordial family and have been observed in order to determine their rotational period, spin pole and shape, which will give insights about their membership and the family evolution. The photometric data are obtained mainly by the University of Athens Observatory (UOAO). Models of the asteroids are derived by the lightcurve inversion method, which is stored in the Database of Asteroid Models from Inversion Techniques (DAMIT).

Reference: D. Athanasopoulos, K. Gazeas, M. Delbo, 2020, EPSC, 14, 733

Further Dissemination - Public Outreach

The secret charm of asteroids

K. Gazeas


Irregularly shaped bodies wandering in the Solar System: these are the asteroids that are being studied by dozens of scientists around the world. The Greek research community is gaining an increasingly crucial role in the identification and characterization of asteroids. A typical example is the organization of the international program "Ancient Asteroids" by the University Observatory of Athens on the initiative of the lecturer of Observational Astrophysics at the National and Kapodistrian University of Athens Dr. Kosmas Gazeas, which attracted the collaborations of Observatories of the world. As part of this research project, researchers are calling on professional and amateur astronomers to raise their telescopes and locate asteroids. We spoke with the architect of the program, who explained to us what scientists are looking for, why it is important to study such bodies and how the "watchful eyes of astronomers", as the researcher characterizes amateurs, contribute to the enrichment of scientific knowledge.

Reference: BHMA Science 2021, by P. Tsiboukis

Ancient Asteroids Project

K. Gazeas, D. Athanasopoulos


Ancient Asteroids is an international observing campaign that aims towards the characterization of asteroids, which are members of the most ancient and dispersed collisional asteroid families in the Main Belt of our Solar System. The project was initiated in 2020 at the University of Athens Observatory (UOAO) of the National and Kapodistrian University of Athens, Greece by Dr. Kosmas Gazeas, in collaboration with the Observatoire de la Côte d'Azur (OCA) in Nice, France, the Aristotle University of Thessaloniki in Thessaloniki, Greece, the Astronomical Institute of the Charles University in Prague, Czech Republic, the Lowell Observatory in Arizona, United States and the BSA Observatory in Savigliano, Italy. The project will also contribute valuable information to the Minor Planet Physical Properties Catalogue (MP3C) program that collects information about the physical properties of asteroids in general. The project Principal Investigator, Dr. Kosmas Gazeas, invites professional and amateur astronomers who wish to contribute on the observing campaign, and collect valuable information on primordial asteroid families.

Reference: Eugenides Foundation 2021, by L. Sokkou

Created by K.Gazeas, based on a template from
Image sources include: NASA/JPL/Caltech