The Lyrid Meteors.

The Lyrid Meteors is expected to be visible between Saturday16 and Monday 25 April this year (2022), and will be at peak visibility on Friday 22 April. With the Third Quarter Moon falling on Saturday 23 April, this year will not be the best opportunity to see these meteors, but nevertheless there should be a good chance to see them in cloudless areas. At its peak the Lyrid Meteor shower typically produces about 20 meteors per hour, though higher rates have been recorded. The Lyrid Meteors take their name from the constellation of Lyra, from which they appear to radiate, at a point close to the star Vega, which will be above the horizon for most of the night from most places on Earth this week, setting at about 5.00 am.

 

The Radiant Point (i.e. point from which the meteors appear to radiate) of the Lyrid Meteors. Bruce McClure/Joni Hall/EarthSky/Wikimedia Commons.

The Lyrid Meteors are comprised of debris from the comet C/1861 G1 Thatcher (named after the astronomer A. E. Thatcher, not the politician). This is a long-period comet that spends most of its time in the Oort Cloud, only visiting the inner Solar System once every 415 years, the last occasion being in 1861. When the comet visits the inner Solar System it is heated by the Sun, melting the ices that make up its surface and releasing a trail of dust, which continues to follow the path of the comet. The Earth passes through this trail in April each year, creating a light show as the dust particles burn in the upper atmosphere.

 

The orbit and current position of Comet C/1861 G1 Thatcher. JPL Small Body Database.

Comet C/1861 G1 Thatcher completes one orbit every 415 years on an eccentric orbit tilted at 79.8° to the plane of the Solar System, that takes it from 0.92 AU from the Sun (92% of the average distance at which the Earth orbits the Sun) to 106 AU from the Sun (110 times as far from the Sun as the Earth, and more than three times the distance at which the planet Neptune orbits the Sun). The comet last visited the Inner Solar System in 1891, and is expected to return again in 2306. As a comet with an orbital period of more than 200 years it is considered to be a Long Period Comet.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

 

The Lyrid Meteor Shower.

The Lyrid Meteors is expected to be visible between Thirsday16 and Saturday 25 April this year (2020), and will be at peak visibility on Sunday 29 April. With the Full Moon also falling on Friday 19 April, with the New Moon falling four days after this on Thursday 23 April, this year should provide a good opportunity to see these meteors. At its peak the Lyrid Meteor shower typically produces about 20 meteors per hour, though higher rates have been recorded. The Lyrid Meteors take their name from the constellation of Lyra, from which they appear to radiate, at a point close to the star Vega, which will rise at about 10.30 pm local time from most places on Earth this week.

 The radiant point of the Lyrid Meteors. Stellarium/Phys.Org.

The Lyrid Meteors are comprised of debris from the comet C/1861 G1 Thatcher (named after the astronomer A. E. Thatcher, not the politician). This is a long-period comet that spends most of its time in the Oort Cloud, only visiting the inner Solar System once every 415 years, the last occasion being in 1861. When the comet visits the inner Solar System it is heated by the Sun, melting the ices that make up its surface and releasing a trail of dust, which continues to follow the path of the comet. The Earth passes through this trail in April each year, creating a light show as the dust particles burn in the upper atmosphere.

The orbit and current position of Comet C/1861 G1 Thatcher. JPL Small Body Database.

Comet C/1861 G1 Thatcher completes one orbit every 415 years on an eccentric orbit tilted at 79.8° to the plane of the Solar System, that takes it from 0.92 AU from the Sun (92% of the average distance at which the Earth orbits the Sun) to 106 AU from the Sun (110 times as far from the Sun as the Earth, and more than three times the distance at which the planet Neptune orbits the Sun). The comet last visited the Inner Solar System in 1891, and is expected to return again in 2306. As a comet with an orbital period of more than 200 years it is considered to be a Long Period Comet.

See also...

Follow Sciency Thoughts on Facebook.

The Lyrid Meteors.

The Lyrid Meteors will be at peak visibility between 21 and 22 April  this year, though this is close to a full moon (which occurs on the 25th), so the display will not be good. The meteors, which appear to radiate from the constellation of Lyra, have been visible since the 16th, and will continue till 26 April. At its peak the Lyrid Meteor shower typically produces about 20 meteors per hour, though higher rates have been recorded.

The origin point of the Lyrid Meteors. SpaceWeather.com.

The Lyrid Meteors are comprised of debris from the comet C/1861 G1 Thatcher (named after the astronomer A. E. Thatcher, not the politician). This is a long-period comet that spends most of its time in the Oort Cloud, only visiting the inner Solar System once every 415 years, the last occasion being in 1861. When the comet visits the inner Solar System it is heated by the Sun, melting the ices that make up its surface and releasing a trail of dust, which continues to follow the path of the comet. The Earth passes through this trail in April each year, creating a light show as the dust particles burn in the upper atmosphere.

The orbit and current position of C/1861 G1 Thatcher. Image created using the JPL Small-Body Database Browser.

See also Fireball over Wyoming, Comet C/2011 L4 (PANSTARRS) to reach its closest point to Earth this week, The Earth approaches its perihelion, The Southern Solstice and Possible second meteor shower to coincide with the Geminids.

Follow Sciency Thoughts on Facebook.

The Lyrid Meteors.

Tomorrow, Saturday 21 April 2012, the Earth will cross the orbit of the comet C/1861 G1 (Thatcher), and be showed in material shed from the comet's tail and still following (roughly) the same path. We will not pass particularly close to the comet, which is currently sixty times as far from the Sun as the Earth - outside the main Kuiper Belt.

The orbit of C/1861 (Thatcher). Wolfram Alpha.

C/1861 G1 (Thatcher) is named after its discoverer, A. E. Thatcher (nothing to do with the politician) who discovered it in 1861. It takes 415 years to orbit the Sun, coming at its closest slightly within the orbit of the Earth (0.921 AU compared to Earth's 1.00 AU) and at its furthest reaches 110 times the distance at which the Earth orbits the sun. It last came closest to the Sun in 1861, and will do this again in 2276.

When C/1861 G1 (Thatcher) reaches the inner part of its orbit it is heated by the Sun's radiation, causing the ices in its makeup (water, carbon dioxide and carbon monoxide) to evaporate away. This causes chunks of the surface to break away, as the rocky parts are no longer glued together by the ice. This forms a stream of small rocky particles that continues to follow the orbit of the comet. Each April the Earth passes through this stream, creating a display of meteors, as the rocky particles burn up in our atmosphere. Because these are all following more-or-less the same path, they all appear to originate at the same point in the sky, in the constellation of Lyra, close to the star Vega.

The radial point from which the Lyrid Meteors all appear to originate. NASA/Windows to the Universe/National Earth Science Teachers Association.

See also Images of Vesta, Asteroid 2012 DA14 may pass within 21 000 km of the Earth, Comet C/2011 W3 (Lovejoy) survives a close encounter with the sun, Evidence for a Younger Dryas impact event? and The stability of Neptune's Trojan Asteroids.

Follow Sciency Thoughts on Facebook.

Kepler-19: new planetary system discovered.

On 7 September 2011 a paper appeared on the arXiv astrophysics database at Cornell University Library by a team lead by Sarah Ballard of the Harvard Smithsonian Centre for Astrophysics describing the discovery of a new planetary system, Kepler-19. Kepler-19 is 650 light years fro Earth in the constellation of Lyra and was formerly identified as KOI-84 (Kepler Object of Interest 84). If is a fairly sun-like star, with a slightly lower mass and radius as our sun, it is also slightly cooler and dimmer, and only about half as old.

The Kepler Space Telescope was able to detect a regular dimming of this star, which seemed to imply the transit of a planet with a radius 2.2 times that of the Earth, every 9.29 days. However this dimming was not completely regular; it sped up and slowed down by 5 minutes on a 316 day cycle. This implied the presence of another body, either an unseen additional planet or an undetected star, possibly directly behind Kepler-19.

Ballard et al. constructed a computer model of the Kepler-19 system, using the initial Kepler observations and follow-up observations from the Spitzer Space Telescope, which they used to model a number of different scenarios.

They came to the conclusion that the dimming was caused by a planet, dubbed Kepler-19b, passing in front of the star. This planet, as initially suspected has a radius of 2.2 times that of the earth, though its composition and mass are impossible to determine. This planet orbits its star every 9.29 days, at a distance of slightly less than 0.1 AU (1 AU = the distance between the Earth and the sun so Kepler-19b obits its star at slightly less than 10% of the distance between the Earth and the sun).

This Orbit is perturbed by the presence of a second planet, named Kepler-19c and dubbed the 'Invisible Planet' or the 'Phantom Planet' in the media. This planet would have a maximum size of six times that of Jupiter and a maximum orbital time of 160 days, though this is considered unlikely, the most probably scenario being a planet Earth-sized or smaller, orbiting the star at most once every 30 days. It is thought not to orbit in the same plane as Kepler-19b, as it does not appear to transverse the surface of Kepler-19 as seen from the Earth; this is different to our solar system, where all planets orbit in essentially the same plane of axis.

Model of the Kepler-19 system, showing the orbit of Kepler-19b (black), and possible orbits for Kepler-19c (coloured).

See also PSR J1719-1438b. The Diamond Planet, New Exoplanet: TrES-5 and Exoplanets on Sciency Thoughts YouTube.