Chajnantor

Chajnantor
Name	Chajnantor Plateau
Native name	Altiplano de Chajnantor
Country	Chile
Region	Antofagasta Region
Province	El Loa Province
Elevation m	5100
Coordinates	23°01′S 67°45′W
Population	0 (uninhabited)

Chajnantor Chajnantor is a high Andean plateau in northern Chile noted for hosting major millimeter and submillimeter astronomical facilities. Located on the Altiplano, the plateau’s exceptional elevation and arid climate make it a premier site for observatories operated by institutions such as the National Radio Astronomy Observatory, European Southern Observatory, National Astronomical Observatory of Japan, and consortia managing the Atacama Large Millimeter/submillimeter Array. The site is proximate to landmarks including the Atacama Desert, Salar de Atacama, and the Puna de Atacama.

Geography and Climate

The plateau lies within the Andes mountain chain near the border of Chile and Bolivia and is part of the Altiplano-Puna volcanic complex region. Chajnantor’s coordinates place it above 5,000 metres, comparable to peaks like Licancabur and regions around Sairecabur, with views toward the Salar de Atacama and the Cordillera de la Sal. Climate is hyperarid influenced by the Humboldt Current, South Pacific Anticyclone, and radiative cooling at night; this produces low precipitable water vapor values shared with locations like Mauna Kea and Summit Station. Soils and surfaces reflect Andean geomorphology, including volcanic formations related to the Central Volcanic Zone and nearby calderas such as those in the Puna.

Astronomy and Observatories

Chajnantor hosts arrays and single-dish telescopes central to millimeter and submillimeter astronomy, drawing collaborations from institutions including the Smithsonian Astrophysical Observatory, Max Planck Society, National Institute of Standards and Technology, and the National Science Foundation. Prominent facilities on or near the plateau include the Atacama Large Millimeter/submillimeter Array (ALMA), the Atacama Pathfinder Experiment, and prototypes linked to projects like the Large Millimeter Telescope. Research programs involve agencies such as the European Southern Observatory and the Japan Aerospace Exploration Agency through partnerships with organizations like the Academia Sinica Institute of Astronomy and Astrophysics and the Rijksuniversiteit Groningen. The site’s altitude and atmospheric stability enable observations comparable to those from Submillimeter Array sites and complement radio telescopes such as the Very Large Array and Green Bank Telescope.

History and Development

Exploration of Chajnantor accelerated with twentieth-century surveys by teams from United States Geological Survey and multinational science consortia, influenced by comparative site studies involving Cerro Tololo Inter-American Observatory, Paranal Observatory, and Cerro Pachón. Development milestones include construction phases led by stakeholders like European Southern Observatory and international consortia that established the Atacama Large Millimeter/submillimeter Array and other instruments. Funding and governance intersect with agencies such as the National Science Foundation, European Research Council, and national ministries from Chile, Japan, Taiwan, and Spain, while technical contributions came from corporations including Thales Alenia Space and research groups at Massachusetts Institute of Technology and Max Planck Institute for Radio Astronomy.

Infrastructure and Access

Access and logistics are coordinated with regional authorities like the Antofagasta Region administration and transport agencies working alongside contractors from companies such as Skanska and engineering groups associated with Caterpillar operations. Access routes connect via roads from towns including San Pedro de Atacama and Calama, with air access historically supported by airports at El Loa Airport and logistics from Calama. Power, data, and cryogenic supply chains involve partners like Siemens, ABB Group, and telecommunications providers coordinating with networks such as RedCLARA and satellite services from operators like SES. On-site facilities are designed with standards from organizations such as the International Organization for Standardization and safety protocols aligned with the World Health Organization guidance for high-altitude operations.

Scientific Research and Discoveries

Research conducted at facilities on the plateau has contributed to discoveries in areas linked to institutions like the Harvard–Smithsonian Center for Astrophysics, Max Planck Institute for Astronomy, and universities such as University of Chile and University of Cambridge. Key results include high-resolution imaging of protoplanetary disks studied by groups at California Institute of Technology and mapping of molecular gas in galaxies connected to teams from University of Tokyo and Harvard University. Observations have informed cosmological studies overlapping with work at Planck (spacecraft), Herschel Space Observatory, and collaborations involving the European Space Agency and National Aeronautics and Space Administration. Projects coordinated with the Event Horizon Telescope consortium leverage millimeter capabilities to probe black hole environments studied by researchers at Princeton University and Massachusetts Institute of Technology.

Environmental and Cultural Impact

Environmental management engages Chilean institutions such as the Ministry of the Environment (Chile) and heritage considerations involve organizations like the National Monuments Council (Chile) due to proximity to indigenous territories historically inhabited by Aymara and Quechua communities. Conservation efforts align with research from groups at Pontifical Catholic University of Chile and international NGOs such as Conservation International, addressing concerns similar to those at Atacama Desert conservation sites and protected areas like the Salar de Atacama. Cultural impact assessments have involved anthropologists from University of California, Berkeley and legal frameworks including instruments adopted by the United Nations Educational, Scientific and Cultural Organization and regional offices of the International Union for Conservation of Nature.

Category:Plateaus of Chile