News and Astronomical Events during 2019-2020

 

Announcement


On Sunday 21 June 2020 a partial solar eclipse will be visible from Greece and it will last 1 h and 22 min. The most important timings are:

  • Athens (Obscuration: 11%):
  • Start: 07:49 am
  • Maximum: 08:28 am
  • End: 09:11 am

One sould NEVER observe the Sun with naked eye. Observations of the Sun through a telescope, as well as with any other optical aid (binoculars, lenses, photographic cameras), should always be done with caution, using special filters.

More information can be found on the Press Release.




Announcement


The recently retired infrared observatory was the only telescope to spot a far-off flash of light that holds clues about the physical characteristics of these cosmic mysteries. Black holes aren't stationary in space; in fact, they can be quite active in their movements. But because they are completely dark and can't be observed directly, they're not easy to study. Scientists have finally figured out the precise timing of a complicated dance between two enormous black holes, revealing hidden details about the physical characteristics of these mysterious cosmic objects. The OJ 287 galaxy hosts one of the largest black holes ever found, with over 18 billion times the mass of our Sun. Orbiting this behemoth is another black hole with about 150 million times the Sun's mass. Twice every 12 years, the smaller black hole crashes through the enormous disk of gas surrounding its larger companion, creating a flash of light brighter than a trillion stars - brighter, even, than the entire Milky Way galaxy. The light takes 3.5 billion years to reach Earth. Orbital and ground-based observations have been combined, in order to unveil the fast changing orbit. The University of Athens Observatory (UOAO) has a significant contribution on this study, as it observes OJ287 since 2006 in the frame of 'BOSS Project', which monitors photometrically the brightest blazars. "It is important to black hole scientists that we prove or disprove the no-hair theorem. Without it, we cannot trust that black holes as envisaged by Hawking and others exist at all," said Mauri Valtonen, an astrophysicist at University of Turku in Finland and a coauthor on the paper.

The original publication paper can be found here: (publication)

For further information, you can visit Spitzer, JPL, NASA, BBC News:


Future Events


Our next public event will take place soon. Stay tuned!

Select image to enlarge:

Select image to enlarge:


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 (kgaze@phys.uoa.gr). 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)




Public Nights during the academic year 2019-2020


Public Nights for the academic year 2019-2020 (winter semester) can be found here.

Public Nights for the academic year 2019-2020 (spring semester) can be found here.


Previous Events


Special Events during the academic year 2019-2020


Special public events organized during the academic year 2019-2020:

  • Interactive Exhibition (2019-2020) "Planets In Your Hand"
  • World Space Week 2019 - 6 October 2019 read more...

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