Showing posts with label Amor Group Asteroids. Show all posts
Showing posts with label Amor Group Asteroids. Show all posts

Saturday, 28 December 2024

The Quadrantid Meteor Shower.

The Quadrantid Meteor Shower is one of the brightest meteor showers of the year, often producing over 100 meteors per hour at its peak, which falls around 3-4 January each year, and is predicted to peak at about 8.00 am on Friday 3 January 2025; three days after the New Moon, which falls on Tuesday 31 December, visibility for the shower should be reasonably good. The meteor shower originates in the constellation of Boötes, high in the northern sky, which is slightly confusing, as most meteor showers are named for the constellation in which they originate. This is because the constellation was named in the sixteenth century by astronomer Tycho Brahe, before the introduction of standardised constellations used by modern astronomers, though to make matters a little more confusing, Brahe didn't name the meteors this way either; the name comes from the constellation of Quadrans Muralis, introduced by Joseph Jérôme Lefrançois de Lalande in 1795, and dropped by the International Astronomical Union in 1922. Because Boötes is visible only from the Northern Hemisphere, the Quadrantid Meteor Shower is not visible from the Southern Hemisphere, and is best viewed from northerly locations such as Canada or Scandinavia.

The radiant point of the Quadrantid Meteors (i.e. the point from which the meteors seem to radiate). American Meteor Society.

Meteor streams are thought to come from dust shed by comets as they come close to the Sun and their icy surfaces begin to evaporate away. Although the dust is separated from the comet, it continues to orbit the Sun on roughly the same orbital path, creating a visible meteor shower when the Earth crosses that path, and flecks of dust burn in the upper atmosphere, due to friction with the atmosphere.

The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.

The Quadrantid Meteors are unusual in that they typically are only visible for a few hours either side of this peak, whereas other showers are typically visible for days or even weeks. This is thought to be because they originate from an asteroid (196256) 2003 EH1, rather than the tail of a comet as with most meteor showers. The orbit of this asteroid is tilted at an angle of 71.9° to the plane of the Solar System, so that the Earth only very briefly passes through the debris trail left by it, rather than remaining in it for some time, as is the case with the trail of a comet with an orbit in roughly the same plane as the Earth.

The calculated orbit and current position (196256) 2003 EH1.  JPL Small Body Database

(196256) 2003 EH1 is a 2.6-4.0 km diameter object with a 2017 day (5.52 year) orbital period, with an elliptical orbit tilted at an angle of 70.8° to the plain of the Solar System which takes in to 1.19  AU from the Sun (119% of the distance at which the Earth orbits the Sun) and out to 5.05 AU (505% of the distance at which the Earth orbits the Sun slightly inside the orbit of the planet Jupiter). This means that close encounters between the asteroid and Earth happen occasionally, with the last calculated to have happened in December 1936 next predicted in December 2052.  It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is never closer to the Sun than the Earth is). (196256) 2003 EH1 also has occasional close encounters with the planet Jupiter, with the last having happened in June 1984, and the next predicted for March 2044.

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Monday, 1 January 2024

The Quadrantid Meteor Shower.

The Quadrantid Meteor Shower is one of the brightest meteor showers of the year, often producing over 100 meteors per hour at its peak, which falls on the night of 3-4 January each year, and is predicted to peak at about 10.00 am on Thursday 4 January 2024; as this is only a week before the new moon, which falls on Thursday 11 January, visibility for the shower should be reasonably good.. The meteor shower originates in the constellation of Boötes, high in the northern sky, which is slightly confusing, as most meteor showers are named for the constellation in which they originate. This is because the constellation was named in the sixteenth century by astronomer Tycho Brahe, before the introduction of standardised constellations used by modern astronomers, though to make matters a little more confusing, Brahe didn't name the meteors this way either; the name comes from the constellation of Quadrans Muralis, introduced by Joseph Jérôme Lefrançois de Lalande in 1795, and dropped by the International Astronomical Union in 1922. Because Boötes is visible only from the Northern Hemisphere, the Quadrantid Meteor Shower is not visible from the Southern Hemisphere, and is best viewed from northerly locations such as Canada or Scandinavia.

The radiant point of the Quadrantid Meteors (i.e. the point from which the meteors seem to radiate). American Meteor Society.

Meteor streams are thought to come from dust shed by comets as they come close to the Sun and their icy surfaces begin to evaporate away. Although the dust is separated from the comet, it continues to orbit the Sun on roughly the same orbital path, creating a visible meteor shower when the Earth crosses that path, and flecks of dust burn in the upper atmosphere, due to friction with the atmosphere.

The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.

The Quadrantid Meteors are unusual in that they typically are only visible for a few hours either side of this peak, whereas other showers are typically visible for days or even weeks. This is thought to be because they originate from an asteroid (196256) 2003 EH1, rather than the tail of a comet as with most meteor showers. The orbit of this asteroid is tilted at an angle of 71.9° to the plane of the Solar System, so that the Earth only very briefly passes through the debris trail left by it, rather than remaining in it for some time, as is the case with the trail of a comet with an orbit in roughly the same plane as the Earth.

The calculated orbit and current position (196256) 2003 EH1.  JPL Small Body Database

(196256) 2003 EH1 is a 2.6-4.0 km diameter object with a 2017 day (5.52 year) orbital period, with an elliptical orbit tilted at an angle of 70.8° to the plain of the Solar System which takes in to 1.19  AU from the Sun (119% of the distance at which the Earth orbits the Sun) and out to 5.05 AU (505% of the distance at which the Earth orbits the Sun slightly inside the orbit of the planet Jupiter). This means that close encounters between the asteroid and Earth happen occasionally, with the last calculated to have happened in December 1936 next predicted in December 2052.  It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is never closer to the Sun than the Earth is). (196256) 2003 EH1 also has occasional close encounters with the planet Jupiter, with the last having happened in June 1984, and the next predicted for March 2044.

See also...

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Sunday, 1 January 2023

The Quadrantid Meteor Shower.

The Quadrantid Meteor Shower is one of the brightest meteor showers of the year, often producing over 100 meteors per hour at its peak, which falls on the night of 3-4 January each year, and is predicted to peak at about 4.00 am on Wednesday 4 January 2023; as this is only a few days before the full moon, which falls on Friday 6 January, visibility for the shower may be poor this year. The meteor shower originates in the constellation of Boötes, high in the northern sky, which is slightly confusing, as most meteor showers are named for the constellation in which they originate. This is because the constellation was named in the sixteenth century by astronomer Tycho Brahe, before the introduction of standardised constellations used by modern astronomers, though to make matters a little more confusing, Brahe didn't name the meteors this way either; the name comes from the constellation of Quadrans Muralis, introduced by Joseph Jérôme Lefrançois de Lalande in 1795, and dropped by the International Astronomical Union in 1922. Because Boötes is visible only from the Northern Hemisphere, the Quadrantid Meteor Shower is not visible from the Southern Hemisphere, and is best viewed from northerly locations such as Canada or Scandinavia.

The radiant point of the Quadrantid Meteors (i.e. the point from which the meteors seem to radiate). American Meteor Society.

Meteor streams are thought to come from dust shed by comets as they come close to the Sun and their icy surfaces begin to evaporate away. Although the dust is separated from the comet, it continues to orbit the Sun on roughly the same orbital path, creating a visible meteor shower when the Earth crosses that path, and flecks of dust burn in the upper atmosphere, due to friction with the atmosphere.

The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.

The Quadrantid Meteors are unusual in that they typically are only visible for a few hours either side of this peak, whereas other showers are typically visible for days or even weeks. This is thought to be because they originate from an asteroid (196256) 2003 EH1, rather than the tail of a comet as with most meteor showers. The orbit of this asteroid is tilted at an angle of 71.9° to the plane of the Solar System, so that the Earth only very briefly passes through the debris trail left by it, rather than remaining in it for some time, as is the case with the trail of a comet with an orbit in roughly the same plane as the Earth.

The calculated orbit and current position (196256) 2003 EH1.  JPL Small Body Database

(196256) 2003 EH1 is a 2.6-4.0 km diameter object with a 2017 day (5.52 year) orbital period, with an elliptical orbit tilted at an angle of 70.8° to the plain of the Solar System which takes in to 1.19  AU from the Sun (119% of the distance at which the Earth orbits the Sun) and out to 5.05 AU (505% of the distance at which the Earth orbits the Sun slightly inside the orbit of the planet Jupiter). This means that close encounters between the asteroid and Earth happen occasionally, with the last calculated to have happened in December 1936 next predicted in December 2052.  It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is never closer to the Sun than the Earth is)(196256) 2003 EH1 also has occasional close encounters with the planet Jupiter, with the last having happened in June 1984, and the next predicted for March 2044.

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Saturday, 4 June 2022

Asteroid 2022 KQ5 passes the Earth.

Asteroid 2022 KQ5 passed by the Earth at velocity of about 7.31 km per second and a distance of about 4400 km (0.11 times the average distance between the Earth and the Moon, or 0.03% of the distance between the Earth and the Sun, which is roughly 100 times the distance at which the International Space Station orbits the Earth), at about 5.40 pm on Saturday 30 May 2022. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2022 KQ5 has an estimated equivalent diameter of 3-9 m (i.e. it is estimated that a spherical object with the same volume would be 3-9 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) more than 35 km above the ground, with only fragmentary material reaching the Earth's surface.

The relative positions of 2022 KQ5 and the Earth on at 6.00 pm on Saturday 30 May 2022. JPL Small Body Database.

2022 KQ5 was discovered on 30 May 2022 (the day of its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2022 KQ5 implies that it was the 141st asteroid (object Q5 - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended so that A = 1, A1 = 26, A2 = 51, etc., which means that Q5 = (25 x 5) + 16 = 141) discovered in the second half of May 2022 (period 2022 K - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The orbit and current position of 2022 KQ5. The Sky Live 3D Solar System Simulator.

2022 KQ5 has a 720 day (1.97 year) orbital period, with an elliptical orbit tilted at an angle of 2.06° to the plain of the Solar System which takes in to 1.004  AU from the Sun (100.4% of the distance at which the Earth orbits the Sun) and out to 2.14 AU (214% of the distance at which the Earth orbits the sun and further from the Sun as the planet Mars). This means that close encounters between the asteroid and Earth happen occasionally, with the last calculated to have happened in July 2022 next predicted in June 2025.  It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is never closer to the Sun than the Earth is)2022 KQ5 also has occasional close encounters with the planet Mars, with the last having happened in October 2018, and the next predicted for October 2077.

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