News and Astronomical Events during 2017-2018


Optical activity of the X-ray source 1RXS J051439.2-021615

The X-ray source 1RXS J051439.2-021615 (RA 05h14m39.20s, Dec -02d16m15.00, J2000.0) showed an optical V-band flare, during the night of 25/26 January 2018 (JD=2458114). While the source had a relatively stable luminosity of V=12.84(1) mag during the past days, there was a sudden increase of the observed flux, which started at HJD=2458144.43313 and reached the peak of V=11.85(1) mag at HJD= 2458144.43741 within a few minutes. TYC 4755-59-1 was used as a comparison for the photometric reduction and it was found to be a good standard with V=12.11(1) mag. The observations were obtained in a 3-min cadence and the brightness was increased by 1 mag within 9 minutes with a slope of ∼0.11 mag/minute. An exponential decline was observed until the end of the night, when the magnitude dropped from V=11.85(1) mag to V=12.72(1) mag in approximately 45 minutes. Multi-wavelength observations on this X-ray source are highly encouraged, while the robotic and remotely controlled telescope at the University of Athens Observatory (UOAO) will continue to follow the target in BVRI optical bands in the following days. Questions regarding the current flare and data availability should be directed to Dr. Kosmas Gazeas ( A light curve sample can be found below:

The photometric variability of the X-ray source 1RXS J051439.2-021615 on 26 January 2018.

New Discovery: Dwarf planet Haumea has rings!

While watching a tiny planet eclipse a very distant star, astronomers made an unexpected discovery: The elongated dwarf planet Haumea hosts a 43-mile-wide ring of particles and debris. Haumea is now the first official dwarf planet found to host a ring system, while we knew that this was only a priviledge of the four giant planets of our Solar System (Jupiter, Saturn, Uranus, Neptune) and of the small asteroid Chariklo. The discovery also marks the first time anyone has found rings around an object in the Kuiper belt, a region of icy bodies out beyond the orbit of Neptune.

The University of Athens Observatory (UOAO), and more specifically Dr. K. Gazeas and the student L. Tzouganatos, participated to this observing campaign, while the scientific results are published through the refereed journal Nature.

The original paper can be found here.

A thin band of debris circles the dwarf planet Haumea in an illustration based on the latest discovery. (Illustration by IAA-CSIC/UHU) Read more here: wiki and here: (information)

Future Events

The next public events at UOAO for the academic year 2017-2018 (spring semester) can be found here.

Public Nights during the academic year 2017-2018

Public Nights for the academic year 2017-2018 (winter semester) can be found here.

Public Nights for the academic year 2017-2018 (spring semester) can be found here.

Previous Events

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Special Events during the academic year 2017-2018

Special public events organized during the academic year 2017-2018:

  • Interactive Exhibition (2017-2018) "Planets In Your Hand"
  • Special Event for Kids: 60 of Space Travel - 17 December 2017 read more...
  • Planetary Conjunction of Venus and Jupiter - 13 November 2017 read more...
  • World Space Week 2017 - 8 October 2017 read more...
  • Stellar occultation by Triton - 5 October 2017 read more...

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