Ceres

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This image of Ceres taken by spacecraft Dawn at a distance of 13641 km. image shows bright crater,  Haulani at right. Image Credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / Justin Cowart
Image1: Ceres, Taken by Dawn

Ceres is the only dwarf Planet located in the inner solar system. It is largest object in main asteroids belt that lie in between the orbits of Mars and Jupiter. It was the first member of asteroid belt discovered by Giuseppe Piazzi in January 1, 1801 and declared to be planet in the solar system. But after the discovery of several similar objects in the asteroid belt, rocky Ceres was reclassify as Asteroid in the 1850s and later dwarf planet in 2006. Pluto named after the Roman goddess of Corn and Harvests.

It covers 25 % of the asteroid belt total mass and has Core, Mantle, and Crust. The surface of Ceres is a mixture of water ice and various hydrated minerals such as carbonate and clay with a mean density of 2.162 g/cm3. It has a tenuous atmosphere of water vapor.

Orbit and Rotation

Ceres’s orbit is closer to the orbit of mars and lies between the orbit of Mars and Jupiter, within the asteroid belt. Ceres takes 4.6 earth years to complete one orbit around the sun. it is in a near 1:1 mean motion orbital resonance with Pallas.

Ceres take 9 hours and 4 minutes to rotate on their own axis. Its orbit is about 4o inclined relative to the ecliptic and has moderate eccentric of 0.08. This means that it doesn’t experience a session as other tilted planets do.

Ceres is the vantage point to the transition of Mercury, Venus, Earth, and Mars across the Sun. The most common transits are of Mercury and recently happen in 2006 and 2010. The transit of earth was in 1814 and next will be 2081.

Surface and Structure

Ahuna Mons is only Prominent mountain of Ceres and estimated that it is 5 km high on its steepest side. this Image is taken by spacecraft dawn from 385 km.
Image2: The Ahuna Mons, imaged by Dawn from 385 km

Ceres is primarily made of carbonates and ammoniated phyllosilicates and has Craters, Mountain, and Several bright spots. On a global scale the surface of Ceres is homogeneous.

The surface of Ceres is heavily cratered but none are larger than 280 km in diameter. An unexpectedly large number of Cererian craters have central pits, perhaps due to cryovolcanic processes, and many have central peaks. Ahuna Mons is the only prominent mountain of Ceres and estimated that it is 5 km high on its steepest side.

Bright spot on the surface of Ceres, located in the middle of an 80 km crater called Occator. it is imaged by spacecraft Dawn from 385 km.
Image3: Bright spot in crater Occator, imaged by Dawn from 385 km

Several bright spots of Ceres are caused by a substance on the surface, possibly ice or salts, reflecting sunlight. The brightest spot is located in the middle of an 80 km crater called Occator. Scientists reported that these bright spots on Ceres may be related to a type of salt, particularly a form of brine containing magnesium sulfate hexahydrite.

                       Ceres probably has a solid core, water – ice mantle, and crust. The density of Core and Mantle is estimated to be about 2.46-2.90 and 1.68-1.95 g/cm3. The 40-km thick solid outer crust is a mixture of ice, salts, and hydrated minerals. Under that is a layer that may contain a small amount of brine. This extends to a depth of at least the 100-km limit of detection.

Size and Distance

This image shows the size compression of Ceres with earth and Moon. Ceres is only 27% the radius of earth's moon and approx one thirteenth of the earth's radius.
Image4: Size compression of Ceres with the Earth and the Moon

The mean radius of Ceres is 476 km. It is 27% the radius of the earth’s moon and more than one thirteenth of the earth’s radius. Among Solar System bodies, It is intermediate in size between the smaller asteroid Vesta and the larger moon Tethys. Its surface area is approximately the same as the land area of India. Its mass (9.4×1020 kg) is only 1.3% that of the Earth’s moon.

From an average distance of 257 million miles (413 million kilometers), Ceres is 2.8 astronomical units away from the Sun. From this distance, it takes Sunlight 22 minutes to travel from the Sun to Ceres.

Atmosphere

Ceres has a tenuous water vapor atmosphere. This water vapor may be due to surface ice sublimation or ice volcanoes. The surface of Ceres has unstable water ice within the crater. These ices can sublimate when energetic particles from the sun hit the exposed ice within the crater. Water ice can migrate from the deep layers of Ceres to the surface but escapes in a very short time.

Orbital and escape velocity

The average orbital speed of Ceres is 17.905km/s (61% earth’s orbital speed) and its escape velocity is 0.51 km/s (4.5% earth’s escape velocity).

Magnetosphere

Yet there is no abidance of magnetic field.

 Moons

Ceres does not have any moons.

Rings

There is no known ring found around Ceres.

Habitability

There is no possible sign of life on Ceres, but in past, Ceres’s condition is not the same as today. Scientists believe that there was a subsurface water ocean in the past and life could maybe exist there in the form of very small microbes. The remote detection of organic compounds and the presence of water with 20% carbon by mass in its near surface could provide conditions favorable to organic chemistry.

Human Touch

The dawn spacecraft is the first and so far the only spacecraft to explore Ceres directly. It was launched on 27 September 2007 and reached Ceres on 6 March 2015. The spacecraft took several images and provide lots of information about Ceres’s shape & elemental composition, and its atmosphere.

Dawn entered its first observational orbit around Ceres at an altitude of 13,500 km on 23 April 2015, staying for only approximately one orbit (fifteen days). The spacecraft subsequently reduced its orbital distance to 4,400 km for its second observational orbit (“survey”) for three weeks, then down to 1,470 km for two months and then down to its final orbit at 375 km for at least three months.

During a series of circular orbit around the Ceres, dawn takes several high resolution images. Dawn took the first image of Ceres on 13 January 2015 revealing impact craters and a small high-albedo spot on the surface.  Additional imaging sessions, at an increasingly better resolution, took place on 25 January 4, 12, 19, and 25 February 1 March, and 10 and 15 April, providing information about a bright spots,  Cryovolcanoes, Ahuna Mons, crater occator, etc. The Dawn mission ended on 1 November 2018 after the spacecraft ran out of fuel.

Mythology

In Roman mythology, Ceres was a Goddess of Agriculture, grain crops, the harvest, fertility, motherhood, and the earth. She was the daughter of Saturn and Ops.

She was originally the central deity in Rome’s so-called plebeian or Aventine Triad and then was paired with her daughter Proserpina in what Romans described as “the Greek rites of Ceres”. The Romans saw her as the counterpart of the Greek goddess Demeter, whose mythology was reinterpreted for Ceres in Roman art and literature.

Quick Discover :

Planet Type:

dwarf Planet


Distance from the sun:

2.8 Astronomical unit


Radius:

476 KM


PlutoYear:

4.61 Earth Years


Earth Day:

220 hours


Axial tilt:

4o


Surface gravity:

0.2845 m/s2


Mean density:

2.162g/cm3


Mass:

9.3835×1020 Kg


Moon:

No


Rings:

no


Potantial for Life:

No life

image credit :

image1: https://upload.wikimedia.org/wikipedia/commons/7/76/Ceres_-RC3Haulani_Crater%2822381131691%29_%28cropped%29.jpg

image2: https://upload.wikimedia.org/wikipedia/commons/2/22/PIA20348_crop_-_Ceres%27_Ahuna_Mons_top_view.jpg

image3: https://upload.wikimedia.org/wikipedia/commons/f/f0/PIA20350_crop_-_Occator_from_LAMO.jpg

image4: https://upload.wikimedia.org/wikipedia/commons/1/12/Ceres%2C_Earth_%26_Moon_size_comparison.jpg

Author: ANIKET KUMAR

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