Geminids Meteor Shower

What are the Geminids?

Every year, between mid-November and late December, our planet Earth intersects a region of its orbit populated by various space debris. Unlike other meteor showers, whose meteoroids originate from comet ejections, the Geminids originate from the debris of an active asteroid, 3200 Phaethon.

The name Geminids derives from the fact that various events in the sky appear to radiate from the constellation Gemini.

The Geminids in 2024

The Geminids are visible between November and December with their peak on the night of the 13th to the 14th. The radiant in the constellation of Gemini makes the observation of many events easy, this is because the radiant transits the meridian at around 2:30 in the morning.

The ZHR value corresponds to “Zenith Hourly Rate” which estimates the number of events that an observer can observe per hour in a dark, moonless sky with the radiant at the zenith.

What is asteroid 3200 Phaethon?

The asteroid 3200 Phaethon was discovered on October 11, 1983 by the Infrared Astronomical Satellite. It was Fred Whipple who later associated the activity of the Geminids with the orbit of the asteroid.

This is a “Near Earth Asteroid” from the Apollo group characterized by the inclusion of bodies originating from the asteroid belt between Mars and Jupiter that have orbits with high eccentricity and whose perihelia are located below 1.017 AU. These bodies will have sides ejected from the belt due to gravitational interactions with Jupiter. 3200 Phaethon, with 6.2 km in diameter and a rotation period of just over 3 hours, is one of more than 1600 known asteroids that occupy these orbits.

Radar images of asteroid 3200 Phaethon, captured by the Arecibo Observatory's planetary radar system. Image credit: NASA.

Orbital elements

Reference: NASA-JPL database ( JPL Solar System Dynamics (nasa.gov) ), updated 03/01/2002.

The debris

What makes the asteroid so fascinating is the fact that it shares behaviors similar to comets, namely the ejection of material when it approaches the Sun, something rare that gives it the classification of an active asteroid. The nature of the ejected material is still the subject of study today, having been discovered in 2023, in an article published by Qicheng Zhang et al. – “Sodium Brightening of (3200) Phaethon near Perihelion” that the asteroid's tail is composed of sodium gases and not dust. There are several proposals to explain the origin of the debris, such as the possibility that the body suffered a fracture due to thermal stress during repeated passages at perihelion or a collision with another body. Although some asteroids in the Apollo group are extinct comets, the spectral properties of 3200 Phaethon do not favor this origin.

Reference: Global Meteor Network . Geminids data for 2020, 2021 and 2022. Published on April 21, 2023.

The Geminids ZHR shows a gradual increase to peak intensity and a very rapid decrease in the following days.

How and when to observe the Geminids on OLA in 2024?

The Geminids, like the Perseids, are undoubtedly one of the best meteor showers of the year. Unlike the Perseids, the Geminids have slower velocities and are more likely to have events in each area. In 2024, the period of greatest activity coincides with the week of the full moon, so the best time to catch the debris from asteroid 3200 Phaethon is the week before its peak.

We recommend the week of December 4th to 7th. The second session of the night will always be the best.

Astronomical Observations

You can consult our Astronomical Observation page for more information.