hygieia It is an asteroid found in the main asteroid belt of the solar system, located between the orbits of Mars and Jupiter. It was discovered on April 12, 1849 by the Italian astronomer Annibale de Gasparis at the Naples Astronomical Observatory. The name "Hygieia" comes from the Greek goddess of health and hygiene. Scientists doubt whether Hygieia can be a dwarf planet.
In this article we are going to tell you everything you need to know about the asteroid Higia, its characteristics, discovery and much more.
Key features
Hygiea is the fourth largest asteroid in the asteroid belt, but it is less visible than its 407 km diameter due to its dark surface (7% albedo). It weighs 8,85 × 1019 kg, or 3% of the mass of the asteroid belt. Hygieia is a relatively elongated object, which clearly indicates that Hygieia does not have enough mass to form a dwarf planet, since its own gravity is not strong enough to "clump" its constituent matter into a spherical shape.
As a carbonaceous asteroid, gravity is not strong enough to push rocks towards the center, and its density is very low: around 2100 kg/m3, a little more than twice the density of water. On its surface, the acceleration due to gravity is only 0,09 m/s2. In addition to noticing the minuscule gravity, if you were on its surface, you would see the sun rise every 27,6 hours, which is longer than the length of an Earth day and much longer than usual for asteroids of this size (they tend to spin on their axes much faster).
It is a C-type carbonaceous asteroid whose surface has been determined spectroscopically to have compounds produced by the interaction of water and rock, so it must be hot enough to melt ice at some point. Because the distance from the sun along the orbit varies greatly, the radiation it receives varies greatly in a circle. Of course, the temperature of the sunny side and the shadow side is very different, but it is always very low. The average temperature of Hygieia is approximately -110°C, reaching a "hot" -26°C at altitudes close to the sun.
The Hubble Space Telescope measured its sphericity. It is irregular in shape, with a diameter greater than 500 km and a diameter less than 350 km. These data explain its density as low as 2.100 kg/m3, which does not generate enough force to compact the material, with a surface gravity of 0,09 m/s². This irregularity makes the movement of rotation take 27,6 hours (a little more than an Earth day), while other spherical objects rotate around their axis at a much faster speed.
As a major asteroid, it is named after the Hygieia family, the smaller bodies located on its outer edge. At 17 km/s, it would take about five and a half years to describe its slightly eccentric orbit. (12% outside the circle) around the Sun.
Discovery of Hygieia
The discovery of the asteroid Hygieia took place on April 12, 1849 at the Astronomical Observatory in Naples, Italy. Italian astronomer Annibale de Gasparis was responsible for this significant finding in the history of astronomy.
Annibale de Gasparis was doing a careful observation of the heavens when he identified a celestial object that seemed to move through space independently. Noticing this unusual behavior, he deduced that it was an asteroid, a small rocky body that orbits the Sun in the main asteroid belt, between the orbits of Mars and Jupiter.
The procedure for the discovery of an asteroid involved the meticulous comparison of the positions of celestial objects at different times, accurately recording their movement over time. In the case of Hygieia, this meticulous process led to the confirmation of its asteroidal nature and the assignment of its name in honor of the Greek goddess of health and hygiene.
It must be borne in mind that in the XNUMXth century, technological advances in astronomy were not yet as developed as those we have today. Therefore, the discovery of asteroids like Hygieia implied an arduous work of manual observation and meticulous calculations by astronomers.
Why is Hygieia a dwarf planet?
Hygieia is considered a dwarf planet due to certain characteristics and criteria established by the International Astronomical Union (IAU) to classify celestial bodies in our solar system. The UAI is the organization in charge of defining the terms and criteria for the nomenclature and classification of astronomical objects.
To be classified as a dwarf planet, a celestial object must meet three main conditions:
- Orbit around the Sun: Hygieia meets this condition, since it is an asteroid that moves in an orbit around the Sun, just like the planets.
- Spherical shape: Dwarf planets must have enough mass for their gravity to allow them to assume a nearly spherical shape. Although Hygieia is not one of the largest bodies in the solar system, it is nearly spherical in shape, which meets this criteria.
- It has not cleared its orbit: This condition is essential to distinguish between planets and dwarf planets. The planets must have "cleared their orbit," meaning they have removed or swept away most of the material near their orbit. On the other hand, dwarf planets, such as Hygieia, have not achieved this process due to their smaller mass and size, and their orbit can be shared with other nearby objects.
If Hygieia is considered a dwarf planet, it would be the second planet in the asteroid belt, after Ceres, since the rest of the class is trans-Neptunian. The dwarf planet category was introduced in 2006 to accommodate Kuiper belt objects like Pluto and Eris, preventing the solar system from having dozens or hundreds of "planets" over time. As a result, Ceres was classified as a dwarf planet.
I hope that with this information you can learn more about Higía, its characteristics and how it was discovered.