Astronomers and engineers at the Atacama Large Millimeter/submillimeter Array (ALMA) have brought the observatory’s capabilities to the highest resolution yet. They were able to see features separated by 5 milliarcseconds in observations of the ancient star R Leporis. This is equivalent to seeing a school bus on the moon’s surface, a 15-fold improvement over previous observations of the same object.
The team achieved this by placing antennas in a configuration spanning 16 kilometers (10 miles) and using the highest frequency on the receiver (so-called Band 10). They also used a new calibration method that helped improve the observations.
The work pays off. The observations provide the most detailed look yet at the maser around R Leporis. A maser is just like a laser, but it emits microwaves. In this case, it is a hydrogen cyanide emission found in the cloud surrounding R Leporis.
A schematic view of how the calibration device can be used to determine atmospheric fluctuations allows the team to greatly improve accuracy.
Image source: ALMA (ESO/NAOJ/NRAO)/Y. Asaki et al.)
“This remarkable achievement in high-resolution imaging through ALMA’s advanced capabilities represents a major milestone in our quest to understand the universe. The success of Band 10’s high-resolution observation demonstrates our commitment to innovation and reinforces ALMA’s position as a leader in astronomical discoveries. This project: “We are excited about new possibilities for the scientific community.” statement.
Other new details of the material cloud around R Leporis have emerged at higher resolution; The team was also able to study the movement of this gas. The maser’s emission is at a specific wavelength, and by looking for a Doppler shift — such as the pitch of a siren changing if an ambulance is approaching or moving away — the team can tell whether the gas is coming toward us or away.
An animation shows the motion of hydrogen cyanide as it moves around the star R Leporis
Image credit: Y. Asaki & N. Lira – ALMA (ESO/NAOJ/NRAO)
“It is very exciting to demonstrate the technical feasibility and scientific potential of high-frequency observations on ALMA’s longest baselines,” added John Carpenter, observatory scientist. “We continue to advance ALMA’s capabilities to reveal the secrets of the universe, now with a clearer view than ever before.”
Located 1,350 light-years away, R Leporis is a well-known variable star that shines about 6,700 times as bright as the Sun.
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