Comet C/2025 A6 (Lemmon): View of Dynamic Gas & Dust Tails from Arizona

Comet C/2025 A6 (Lemmon): View of Dynamic Gas & Dust Tails from Arizona

Astrophotographer Andrew McCarthy: "Captured last night—probably the coolest comet shot I've ever gotten. I've never seen such a dynamic tail on a come. Incredible active, and moving quickly, which makes photographing it a challenge." 

Comet Lemmon was discovered early this year as it headed into the inner Solar System. The comet reached its closest point to the Sun on November 8, 2025. It passed nearest to the Earth—about half of the Earth-Sun distance—on October 21.

A comet tail is a projection of material from a comet that often becomes visible when illuminated by the Sun, while the comet passes through the inner Solar System. As a comet approaches the Sun, solar radiation causes the volatile materials within the comet to vaporize and stream out of the comet nucleus, carrying dust away with them.

Blown by the solar wind, these materials typically form two separate tails that extend outwards from the comet's orbit: the dust tail, composed of comet dust, and the gas or ion tail, composed of ionized gases. They become visible through different mechanisms: the dust tail reflects sunlight directly, while the gas tail glows because of the ionization.

Larger dust particles are less affected by solar wind and tend to persist along the comet's trajectory, forming a dust trail which, when seen from Earth in certain conditions, appears as an anti-tail (or antitail) extending in the opposite directions to the main tail.

Initially, a comet's tail may be difficult to observe, but as the comet heats up, it vaporizes its icy nucleus, releasing gas and dust particles that form the tail. This process is known as sublimation, where the heat causes the comet's volatile materials to vaporize and stream out, creating a cloud of gas and dust around the nucleus.

The tail typically points away from the Sun due to the solar wind's influence, but as the comet approaches perihelion, the tail becomes more prominent and extends further away from the Sun.  As the comet recedes from the Sun, the tail's length may decrease, and its direction may change based on the comet's trajectory and the effects of solar wind.

Arizona is a landlocked state in the Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the northwest and California to the west, and shares an international border with the Mexican states of Sonora and Baja California to the south and southwest. 

Image Credit: Andrew McCarthy

Andrew's website: https://cosmicbackground.io

Image Date: Oct. 26, 2025

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