What is AGB in astronomy?

Published by Charlie Davidson on

What is AGB in astronomy?

The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (0.6–10 solar masses) late in their lives.

What is the AGB phase?

As the star evolves through the AGB phase, it cools, expands, and grows in brightness, burning its nuclear fuel faster and faster. For massive AGB stars larger than a few solar masses, the star can cool to such an extent that dust begins to condense in the outer convective envelope.

What is a post AGB star?

Post-AGB stars are luminous objects of low and intermediate initial mass (M* ≤ 8–9 M⊙) in a final stage of evolution: they ended their Asymptotic Giant Branch (AGB) evolution by a phase of very strong mass loss (10−7–10−4 M⊙ yr−1), evolve on a fast track to hotter effective temperatures at roughly constant luminosity …

How do AGB stars lose mass?

During a star’s post-main-sequence (MS) evolution, it will lose much of its starting mass through stellar winds. In addition, all of this excess material being blown off of the star means that AGB stars are often surrounded by a lot of dust.

What does AGB stand for?

AGB

Acronym Definition
AGB Automatic Gear Box
AGB Autonomous Guided Bomb
AGB Air Guard Base (US military)
AGB American Guitar & Band

What color is a red supergiant?

Red supergiants look red because of their low surface temperatures. They range from about 3,500 – 4,500 Kelvin. According to Wien’s law, the color at which a star radiates most strongly is directly related to its surface temperature.

Where is a star born?

Orion Nebula
Stars are born within the clouds of dust and scattered throughout most galaxies. A familiar example of such as a dust cloud is the Orion Nebula. Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction.

What does AGB stand for medical?

Amounts Generally Billed
Amounts Generally Billed (AGB) – AGB refers to a method of reviewing past claim insurance payments and dividing by total billed claim amounts. The AGB number is used to calculate total financial responsibility thresholds for patients that are eligible for financial assistance. The AGB is recalculated every year.

What happens to a star during the AGB phase?

For M-type AGB stars, the stellar winds are most efficiently driven by micron-sized grains. Thermal pulses produce periods of even higher mass loss and may result in detached shells of circumstellar material. A star may lose 50 to 70% of its mass during the AGB phase.

What kind of stars are in the asymptotic giant branch?

H–R diagram for globular cluster M5, with known AGB stars marked in blue and some of the more luminous red giant branch stars in red. The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars.

Which is the main source of energy in the AGB stage?

AGB stage. The AGB phase is divided into two parts, the early AGB (E-AGB) and the thermally pulsing AGB (TP-AGB). During the E-AGB phase, the main source of energy is helium fusion in a shell around a core consisting mostly of carbon and oxygen.

What happens to the atmosphere of a born again star?

The outer atmosphere of the born-again star develops a stellar wind and the star once more follows an evolutionary track across the Hertzsprung–Russell diagram. However, this phase is very brief, lasting only about 200 years before the star again heads toward the white dwarf stage.

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