Astronomers have mapped the changes in the rotation speed of the Sun’s chromosphere for the first time using 100 years of daily records of the Sun at the Kodaikanal Solar Observatory. This research can help in presenting a complete picture of the inner workings of the Sun.
According to this study, the Sun’s equatorial region rotates much faster than its polar regions . Because, the Sun’s poles take 35 days to complete one rotation, while the equatorial region takes only 25 days to complete one complete rotation.
Such findings are important for understanding solar dynamics and their impact on Earth.
About the research
Mapping of Differential Rotation
- The research used daily records collected over 100 years at the Kodaikanal Solar Observatory, one of only two global observatories to archive such extensive solar data .
- The extensive data collected here allowed researchers to analyse solar features such as plumes and network cells, providing insights into the Sun’s rotational activity.
Indian Institute of Astrophysics
- It was established in Madras (now Chennai) in the year 1786. It was established as an autonomous institution in the year 1971. It is headquartered in Bengaluru.
- Its main observation complexes (facilities) are located at Kodaikanal, Kavalur, Gauribidanur and Hanle .
Importance of chromospheric characteristics
- Plages and network cells are the key components in this study. These features are continuously present on the solar surface, unlike sunspots, which occur transiently and at limited latitudes , allowing scientists to measure rotation rates even at the poles.
- Plages are bright areas with weak magnetic fields. They are reflected in the chromosphere and are much larger than sunspots. Their size is 3 to 10 times larger than sunspots.
- Network cells are convective structures with weak magnetic fields. They are about 30,000 kilometers in diameter. They are slightly larger than individual sunspots, but smaller than sunspot groups.
- Their analysis revealed a clear differential rotation, indicating that the rotation rate was about 13.98 degrees per day at the equator and 10.5 degrees per day near the poles .
Rotation of the earth and the sun
- Rotation of the Earth: The Earth rotates as a rigid body, and completes one full rotation every 24 hours, uniformly at all locations.
- Differential rotation of the Sun: Unlike the Earth, the Sun rotates at different speeds depending on the latitude. The Sun is a giant ball of plasma. Due to which differential rotation is observed here i.e. it rotates faster in the equator and slower at the poles.
Importance of Differential Rotation
- The Sun’s differential rotation is important in understanding its internal dynamics, as it drives the solar dynamo responsible for the 11-year solar cycle .
- This interaction between differential rotation and the Sun’s magnetic field is responsible for intense solar activity, such as solar flares and magnetic storms, which can affect Earth’s space environment.
layers of the sun’s atmosphere
The Sun’s atmosphere is composed of several layers, primarily the photosphere, the chromosphere, and the corona.
1. Photosphere
- Description: It is the visible surface of the Sun that emits light.
- Size: About 500 kilometres (310 mi).
- Temperature: about 5,500°C (9,932°F)
2. Chromosphere
- Description: It is the upper layer of the photosphere, visible during a solar eclipse.
- Size: About 2,000 kilometres (1,240 miles).
- Temperature: Its lower part is heated up to 4,500°C (8,132°F) and the upper part is about 20,000°C (36,032°F).
3.Corona
- Description: It is the uppermost layer of the Sun’s atmosphere, visible during a total solar eclipse.
- Size: It extends millions of kilometres into space.
- Temperature: It is extremely hot. Its temperature ranges from 1 to 3 million degrees Celsius (1.8 to 5.4 million degrees Fahrenheit).
Speciality
- Solar wind: A stream of energetically charged particles (mostly electrons and protons) moving outward from the Sun.
- Coronal mass ejections (CMEs): These are massive eruptions of solar winds and magnetic fields that rise from the solar corona or travel into space.