Abu Dhabi: «Gulf»
Today, Saturday (December 24), the International Astronomy Center’s Astronomical Seal Observatory was able to monitor and photograph a rare astronomical phenomenon observed from regions of the United Arab Emirates, namely the disappearance of a star for 8 seconds, due to the passage of a asteroid called “Thuli” (279 Thule) in front of one of the stars of the constellation called Taurus (HIP 20917).
This phenomenon can only be monitored from certain areas located within a narrow strip the width of which does not exceed 130 kilometers that crosses 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 so happened that this narrow strip passed over the Seals Astronomical Observatory in the Seals area in the Emirate of Abu Dhabi.
The engineer Muhammad Shawkat Odeh, director of the International Astronomy Center, said that the asteroid “Thuli” has a diameter of only 126 kilometers, and was at the time of occultation at a distance of 474 million kilometers from the Earth. while the star is 37 light years away from us.
And previous astronomical calculations for the observatory’s website showed that the asteroid will cross in front of the star and the occultation will start on Saturday, December 24 at 03:00 28 minutes UAE time, and the occultation will last only 8 seconds, and during this time the star will disappear from view due to the passage of the faint asteroid in front of it.
In preparation for the occultation, the Astronomical Seal Observatory’s main telescope, which is 14 inches in diameter, was pointed at the star at three in the morning, and as soon as the telescope was pointed at it, it was clearly visible through the instruments, and the star remained visible until it disappeared at 03:03, 27 minutes 59.953 seconds, and the occultation continued for 8 seconds, until the star reappeared at 03:03, 28 minutes and 08.460 seconds.
This observation is considered a difficult astronomical observation for several reasons, including the relative darkness of the brightness of the star and the asteroid, since the star shines from magnitude 7.7 and the asteroid from magnitude 14.6, and these values require a sensitive camera being able to photograph the star during an exposure period of only 0.03 seconds. In addition, the occultation has occurred and the star is only 25 degrees low in the sky, which makes it appear lighter and increases the turbulence of the atmosphere above it. Interestingly, the occultation occurred after the passage of a cloud mass that covered the area for several hours prior to the occultation, and the sky remained clear for a short time at the time of the occultation, so that less than one hour after the occultation a large cloud cover entered.
It should be noted that the occultation of stars by asteroids is usually immediate, because stars are point sources of insignificant diameter as seen from the earth, except that in some cases the occultation does not occur immediately and the star gradually disappears, and is that which happened in this occultation because the star needed. It takes about a second for it to disappear completely, 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 have been 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 of the moon, the determination of the shape and size of some asteroids, the identification and review 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 the satellites of some asteroids . Therefore, the International Astronomy Center attaches great importance to such phenomena and provides the result of its observations to international bodies interested in such observations, including the Astronomical Conjunctions Timing Organization in the United States.
