The disappearance of a star from the UAE sky for 8 seconds

 The Astronomical Seal Observatory of the International Astronomy Center was able, at dawn today, Sunday, to monitor and photograph a rare astronomical phenomenon that was seen from regions in the UAE, which is the disappearance of a star for 8 seconds, due to the passage of an asteroid named “Thuli” (279 Thule) in front of a Taurus star called (HIP 20917).

This phenomenon can only be monitored from certain areas located within a narrow strip whose width does not exceed 130 kilometers that crossed the southern half of the UAE and some neighboring countries, including parts of the Sultanate of Oman, Qatar, Bahrain, northern Saudi Arabia, southern Jordan and southern Palestine. It happened that this narrow strip passed over the Astronomical Seal Observatory in the Seal area in the Emirate of Abu Dhabi, according to the International Astronomy Center.

Engineer Muhammad Shawkat Odeh, Director of the International Astronomy Center, said that the diameter of the asteroid "Thuli" was only 126 km, and it was located at the time of occultation at a distance of 474 million km from Earth, while the star is 37 light years away from us. Prior astronomical calculations for the observatory's website showed that the asteroid will pass in front of the star and occultation will begin on Saturday, December 24 at 03 am and 28 minutes UAE time, and the occultation will last for only 8 seconds, and during this period the star will disappear from view due to the passage of the faint asteroid in front of it.

In preparation for the occultation, the main telescope of the Astronomical Seal Observatory, which has a diameter of 14 inches, was directed towards the star at three o’clock in the morning, and as soon as the telescope was directed towards it, it was clearly seen through the devices, and the star remained visible until it disappeared at 03 am, 27 minutes and 59.953 seconds, and the occultation continued. For 8 seconds, until the star reappeared at 03:03 am, 28 minutes and 08.460 seconds.

The Director of the International Astronomy Center added that this observation is one of the difficult astronomical observations for several reasons, including the relative dimness of the luminosity of the star and the asteroid, as the star shines from magnitude 7.7 and the asteroid shines from magnitude 14.6, and these values ​​require a sensitive camera to be able to photograph the star during an exposure period of only 0.03 seconds. . Also, the occultation occurred and the star is located at a low altitude in the sky of only 25 degrees, which makes it appear lighter and increases the turbulence of the atmosphere on it. He pointed out that the occultation occurred after the passage of a mass of clouds that covered the area for several hours before the occultation, and the sky remained clear for a short period at the time of the occultation, so that less than an hour after the occultation a large cloud cover entered.

It should be noted that the occultation of stars by asteroids is usually immediate because the stars are point sources of no significant diameter as seen from the earth, except that in a few cases the occultation does not occur immediately and the star gradually disappears, and this is what happened in this occultation as the star needed to It takes approximately one second for it to completely disappear, indicating that this star has a significant apparent diameter.

Astronomical occultations are among the astronomical phenomena that provide valuable information to scientists, through which many discoveries were made, including the discovery of the rings of Uranus and Neptune, the determination of the apparent diameters of some stars, the determination of the shape of the edges of the moon, the determination of the shape and sizes of some asteroids, the identification and revision of the orbits of the planets and asteroids of the solar system, and from The most important discoveries made by observing occultations is the discovery of satellites of some asteroids. Therefore, the International Astronomy Center attaches great importance to such phenomena, and provides the result of its observations to the international bodies concerned with these observations, including the Astronomical Conjunctions Timing Organization in the United States.