Arquivo para December 15th, 2021

The Leonard Christmas Comet

15 Dec

Discovered January of this year by astronomer G.J. Leonard of the University of Arizona from the Mount Lemmon Observatory in Tucson, Arizona, the small celestial body Comet Leonard has an orbital period of 80,000 years, and has been seen in the northern hemisphere as it approaches Earth, and will now be seen in the coming weeks from the 15th in the southern hemisphere.

Technically called C/2021, it is reversing its visibility position from the north to the south of the planet, so residents of the southern hemisphere will be able to see it, albeit small.

The closest approach distance to the Earth was 34 million kilometers on December 12th, now it heads towards the Sun, on December 18th it will already be close to Venus, at 42 million kilometers and it will orbit the sun on January 3rd 2022, at a distance of 90 million km, these distances are small in spatial terms, but due to its size it will be seen as a weak point until then, with a telescope and knowing its orbit it will be easier to see it.

The comet travels at a speed of 70 km/s, and despite the expectations being very good, it is necessary to remember that it will be closer and closer to the Sun and brings the possibility of losing strength, in general they are unpredictable and the closer to the Sun the more they can lose how to increase their brightness, so how bright their tail will be in our hemisphere is not quite certain, in the northern hemisphere observation was made more easily with the help of instruments, even a small telescope.

The observations made so far there has been an increase in luminosity due to a phenomenon known as frontal scattering, dust particles ejected from the comet cause a refraction of light, when the angle between the comet in relation to the Earth and the Sun is very large (larger than 160º), as its trajectory is perpendicular to the earth, this will be happening these days from December 14th and 16th, but the scattering depends on the size of the particles and of course, if the sky is clear, in southern Brazil there are rains at this time.

Unlike comet Neowise, which was brightest in the northern hemisphere in 2020, this time Leonard will be more visible in the southern hemisphere, being visible on the horizon, each night from today it will be more visible further up towards the planet Venus ( incorrectly called the Dalva Star), and it will be more visible longer until the 18th because appearing later the sky will be darker.

You need to look for a place with good visibility, low local light and open skies, and look to the west horizon, until January 3rd when the sun approaches and it will start to get weak.

URGENT: Launch of James Webb Space Telescope postponed to 12/24.