Lyrid meteor shower: Leftovers of Comet Thatcher

The Lyrids are a prominent meteor shower that peaks in late April. While the shower is not as flashy as others during the year, the Lyrids have been known to have unusual peaks of activity. A typical shower displays between five and 20 meteors an hour at the peak, but some of the more spectacular shows have 100 or more meteors an hour.

This year, the shower will pass by Earth around April 16-25, and the peak is expected to be shortly before dawn on April 22.

Related: Lyrid meteor shower 2020: When and how to see it

Chinese astronomers recorded the shower as far back as 687 B.C., according to NASA. The source for the meteors is Comet Thatcher, which was discovered by amateur astronomer A.E. Thatcher on its last closest approach to the solar system in 1861. The comet is expected to return in 2276.

Historical Lyrids sightings

The Lyrids have been chronicled in many cultures over the past 2,700 years. Chinese astronomers noted prominent displays in 687 B.C. and 15 B.C. Also, in 1136, a report from Korea chronicled the shower with the words “many stars flew from the northeast,” according to Space.com’s skywatching columnist Joe Rao.

In 1803, residents of Richmond, Virginia, went outside late at night after a fire alarm. A report from that time noted that the meteors resembled rockets in the sky.

“Shooting stars. This electrical [sic] phenomenon was observed on Wednesday morning last at Richmond and its vicinity, in a manner that alarmed many, and astonished every person that beheld it. From 1 until 3 in the morning, those starry meteors seemed to fall from every point in the heavens, in such numbers as to resemble a shower of sky rockets,” wrote a journalist at the time, in an account republished on Space Weather.

NASA stated that similarly impressive shower sightings took place in 1922 in Greece, 1945 in Japan, and 1982 in the United States.

The shower’s radiant is located at the center of this stellar map, in the constellation Lyra. (Image credit: © Dominic Ford/In-The-Sky.org)Where the Lyrids are

The Lyrids look like they’re coming from Vega, a bright start in the constellation Lyra, which the shower is named after. The “radiant” point is easy to spot in the summer sky because Vega is one of the brightest stars, making it visible even in spots with light pollution. The meteors, however, are best viewed under dark skies. 

Lyra’s precise location is:

Right ascension: 19 hoursDeclination: 40 degreesLatitudes: Between 90 and -40 degrees

NASA recommends that skywatchers go outside after Lyra rises (after 9 p.m. local time), and after moonset, to watch the show, which runs until dawn. Allow 30 minutes for eyes to adjust, and look away from the radiant, where longer and more spectacular meteors will be visible. Gazing at Lyra directly will show short meteors due to a phenomenon known as foreshortening.

While the Lyrids are not the brightest ones out there, NASA said the meteors “are known for their luminous dust trains, which can be observable for several seconds.” A typical meteor from that shower moves about 30 miles (49 kilometers) per second.

Although the shower appears to come out of Lyra, the meteors are actually chunks that have sloughed off of Comet Thatcher.

Related: The greatest comet close encounters of all time

Comets disintegrate as the sun’s heat causes ice and other debris to break off from the core. This leaves a trail of rubble in space. In the case of Thatcher’s path of debris, the Earth runs into it once a year and produces the sky show known as the Lyrid meteor shower.

It’s hard for astronomers to predict which years will produce more spectacular showers, the North American Meteor Network noted in a report from 1999.

“The orbit determination relies heavily on photographic and radar results, which are seldom obtainable every year — hence gaps in the data and our knowledge of the shower,” the network wrote. “Studies of the years with higher Lyrid activity have found, however, that outbursts of fainter meteors occurred prior to the normal meteor maximum.”

Additional resources:

This article was update on April 16, 2020 by Space.com Reference Editor Kimberly Hickok. 

Source: space.com

Tags: 2020, all, best, dark, Data, hard, how to, Image, it, japan, M, Map, moves, NASA, or, place, see, show, shows, Sky, Space, update, year

Thanks! You've already liked this
136 views