Band-like clouds seen over Sun’s neighbour-Luhman 16A

A group of international astrophysicists have identified cloud bands on the surface of Luhman 16A, one of a pair of binary brown dwarfs in the Vela constellation.

They have used an idea put forth Indian astrophysicist Sujan Sengupta, who is at the Indian Institute of Astrophysics, Bengaluru, that the light emitted by a cloudy brown dwarf, or reflected off an extrasolar planet, will be polarised.

He suggested that a polarimetric technique could serve as a potential tool to probe the environment of these objects.

Subsequently, many astronomers detected the polarisation of brown dwarfs. But what is special in the newest study of Luhman 16 is that the researchers have found the actual structure of the clouds — that they form bands over one of the pair (Luhman 16A) of brown dwarfs.

Luhman 16A

Luhman 16 is a binary star system, the third closest system to the Sun after Alpha Centauri and Barnard’s star.

At a distance of about 6.5 light years from the Sun, this pair of brown dwarfs referred to as Luhman 16A and Luhman 16B orbits each other, casting a dim light.

Brown Dwarfs

Brown dwarfs are objects which have a size between that of a giant planet like Jupiter and that of a small star. In fact, most astronomers would classify any object with between 15 times the mass of Jupiter and 75 times the mass of Jupiter to be a brown dwarf.

Given that range of masses, the object would not have been able to sustain the fusion of hydrogen like a regular star; thus, many scientists have dubbed brown dwarfs as "failed stars".

Starting in 1995, astronomers have been able to detect a few nearby brown dwarfs. All of the brown dwarfs discovered so far are parts of a binary system. A binary system is one in which two stars orbit around one another (just like the planets of our solar system orbit our star, the Sun).

It is believed that some of the more massive brown dwarfs fuse deuterium or lithium and glow faintly.

The faintness of the glow proved to be providential in finding the cloud bands. Unlike a star whose brightness would be too high, or an extrasolar planet orbiting a star, where the extra light from its star would have to be cut off to make the measurement, the light of the brown dwarfs was just right.

The group, by using the Very Large Telescope at European Southern Observatory, Chile, found that Luhman 16A had band-like clouds in its atmosphere, whereas the same was not true of Luhman 16B.

Source: TH/WEB

Join Our Telegram

Oceanic Anoxic Event 1a and MASS EXTINCTION

Oceanic Anoxic Event 1a and MASS EXTINCTION

25 Dec, 24
SHARE

Oceanic Anoxic Event 1a from the Paris Basin (Environment) Paper-3 PMP OAE 1a refers to a period during the Cretaceous Period (145 million years ago and ended 66 million years ago) when Earth's oceans became depleted of oxygen, causing a significant disruption in marine life. Cause: The event is believed to have been

Viksit Panchayat Karmayogi (Good governance)

26 Dec, 24
SHARE

Viksit Panchayat Karmayogi (Good governance) Governance GS PAPER-2 PMP Dr. Jitendra Singh launched the ‘Viksit Panchayat Karmayogi’ initiative on Good Governance Day, celebrated to mark the 100th birth anniversary of former Prime Minister Atal Bihari Vajpayee. The initiative, which is part of the broader ‘Prashasan Gaon

Major programmes to control Air Pollution

23 Dec, 24
SHARE

Major programmes to control Air Pollution National Clean Air Programme? It was launched by the Ministry of Environment, Forests and Climate Change (MoEFCC) in January 2019. It is the first-ever effort in the country to frame a national framework for air quality management with a time-bound reduction target. The

Air pollution and Air quality Measures in India

21 Dec, 24
SHARE

Air pollution and Air quality Measures in India (Environment) GS Paper-3 P-M-P Air pollution may be defined as the presence of any solid, liquid or gaseous substance including noise and radioactive radiation in the atmosphere in such concentration that may be directly and/or indirectly injurious to humans or other l

Geopolitical Significance of Ports

20 Dec, 24
SHARE

Geopolitical Significance of Ports (IR) Act as geopolitical assets: Ports enhance the projection of strategic reach, which helps strengthen the country’s control over important sea and energy supply routes. E.g. Indian Navy’s staging base at Agalega Islands will enable marine patrols