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JHKstands forJ-H-K Infrared Photometric System
Full Form of JHK
What is JHK?
The JHK refers to the J, H, and K infrared photometric bands, a standardised system used by astronomers worldwide to measure the brightness of celestial objects at near-infrared wavelengths. The J-band centres around 1.25 micrometres, the H-band around 1.65 micrometres, and the K-band around 2.2 micrometres, together covering a portion of the electromagnetic spectrum where cooler stars, dust-embedded protostars, and distant galaxies become observable. In India, the JHK system is extensively used by institutions such as the Indian Institute of Astrophysics in Bengaluru and the Physical Research Laboratory in Ahmedabad, particularly through observatories like the Himalayan Chandra Telescope at Hanle in Ladakh, which operate at high altitudes to minimise atmospheric water vapour absorption. The system allows Indian astronomers to study stellar populations, star-forming regions, and the structure of the Milky Way with remarkable precision. For students preparing for CSIR-NET in Physical Sciences, UPSC, or postgraduate astrophysics entrance exams, familiarity with JHK photometry is considered essential, as questions on photometric systems frequently appear in both the general astronomy and instrumentation sections.
JHK का फुल फॉर्म
जे-एच-के अवरक्त प्रकाशमितीय तंत्र
Example
Researchers at the Indian Institute of Astrophysics recently published JHK photometry of young stellar objects in the star-forming cloud near NGC 7538, revealing previously undetected low-mass protostars.
JHK — frequently asked questions
What is the full form of JHK in astronomy?
JHK stands for the J, H, and K infrared photometric bands, which together form a standard near-infrared photometric system used to measure the brightness of stars and other celestial objects.
Why is the JHK photometric system important?
It allows astronomers to observe cooler objects, penetrate dust clouds, and study star-forming regions that are invisible in optical wavelengths, making it indispensable for infrared astronomy.
Where is the JHK system used in India?
Indian observatories such as the Himalayan Chandra Telescope at Hanle in Ladakh and the Vainu Bappu Observatory in Tamil Nadu routinely use JHK photometry for stellar and galactic research.