11364 Hs

The Mysterious Asteroid 11364 Hs

Asteroid 11364 Hs is a rocky body orbiting the Sun in the main asteroid belt between Mars and Jupiter. Not much is known about this small asteroid, but what we do know raises some fascinating questions.

Discovery and Naming

11364 Hs was discovered on March 23, 1998 by the Lincoln Near-Earth Asteroid Research (LINEAR) team in New Mexico. The asteroid was given the provisional designation 1998 FQ144 before being officially numbered and named 11364 Hs in 2007.
The name Hs stands for the Hsüan Yeh astronomical observatory in Taiwan, which has discovered numerous asteroids over the years. Naming asteroids after observatories is a common practice to honor their contributions to studying these space rocks.

Orbit and Classification

11364 Hs orbits the Sun in the central main belt at an average distance of 2.56 astronomical units. With an eccentricity of 0.159, its orbit is moderately elliptical, ranging from 2.14 AU at perihelion (closest approach to the Sun) to 2.99 AU at aphelion (farthest distance).
Based on its spectrum, 11364 Hs is classified as an S-type asteroid. This means its composition likely consists of silicates and metals – basically, your typical rocky asteroid material.

Size and Rotation

Estimates for 11364 Hs’s diameter range from 5.1 to 11.5 kilometers. So it’s likely a medium-sized asteroid, albeit on the smaller end of the scale.
As for its rotation, that’s where things get really interesting. Observations suggest 11364 Hs has an exceptionally slow spin rate, taking about 1 year to complete one full rotation! This makes it one of the slowest rotating asteroids we’ve ever discovered.

The Mystery of the Sluggish Spin

Why does 11364 Hs rotate so slowly compared to most asteroids, which typically have spin periods measured in hours or days? Astronomers aren’t exactly sure.
One possibility is that 11364 Hs has a rubble pile structure – meaning it’s not a solid boulder, but rather a loose “pile” of rocks and debris held together by gravity. Rubble pile asteroids often rotate slowly due to internal friction dissipating their kinetic energy.
However, 11364 Hs doesn’t show definite signs of being a rubble pile in terms of its lightcurve (how its brightness varies over time). So the reason for its sluggish spin remains an open question.

YORP Effect

Another process that can alter an asteroid’s spin over long timescales is the YORP effect. This phenomenon is caused by sunlight asymmetrically heating the asteroid’s surface as it rotates, giving it a gentle “torque” over millions of years.
In some cases, the YORP effect can actually speed up an asteroid’s rotation until it breaks apart. So could 11364 Hs be an asteroid that had its spin dramatically slowed by the YORP effect in the past? More observations are needed to test this hypothesis.

Past Collision?

Finally, astronomers have speculated that 11364 Hs could have had its spin altered by a past collision with another asteroid. If it was hit just right, the impact could have transferred angular momentum away and slowed the asteroid’s rotation substantially.
Again, no strong evidence for such an impact exists yet in 11364 Hs’s shape or surface features. But a past collision can’t be definitively ruled out either.

Opportunities for Future Study

11364 Hs presents a fascinating target for continued asteroid research. Further lightcurve observations and modeling are needed to better constrain its size, shape, composition, and the possible explanations for its exceptionally slow spin rate.
If it does turn out to have a rubble pile structure, 11364 Hs would provide a great chance to study such loose asteroid aggregations in more detail compared to faster rotating rubble piles. Rubble pile asteroids are thought to be quite common, so solving the mystery of 11364 Hs could have broader implications.

Spacecraft Visit?

Looking ahead, perhaps a future spacecraft could visit 11364 Hs, map its surface with images, and even land on it to test its interior structure directly! After the recent successes of missions like NEAR Shoemaker, Hayabusa2, and OSIRIS-REx visiting asteroids, an exploratory mission to 11364 Hs doesn’t seem out of the question someday.