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Webb traces details of complex planetary nebula – More than one star contributes to the irregular shape of NGC 6072

Webb’s newest look at planetary nebula NGC 6072 in the near- and mid-infrared shows what may appear as a very messy scene resembling splattered paint. However, the unusual, asymmetrical scene hints at more complicated mechanisms underway, as the star central to the scene approaches the very final stages of its life and expels shells of material, losing up to 80 percent of its mass.

Since their discovery in the late 1700s, astronomers have learned that planetary nebulae, or the expanding shell of glowing gas expelled by a low-intermediate mass star late in its life, can come in all shapes and sizes. Most planetary nebulae present as circular, elliptical, or bi-polar, but some stray from the norm, as seen in new high-resolution images of the planetary nebula NGC 6072 by the NASA/ESA/CSA James Webb Space Telescope.

colourful mostly red image of near-infrared light from a glowing cloud with a distorted, asymmetrical shape, illuminated from within by a bright central star. The asymmetrical shape resembles paint splattered on the ground. In the centre of this image, a light blue glow casts over areas of dark pockets that appear dark blue and are traced with orange material. It has a clumpy appearance. The shells become a deeper red with distance from the centre. The shells appear as lobes that push gas toward the equatorial plane, forming a disc. The background of the image is black and speckled with tiny bright stars and distant galaxies. — The NASA/ESA/CSA James Webb Space Telescope’s view of planetary nebula NGC 6072 in the near-infrared shows a complex scene of multiple outflows expanding out at different angles from a dying star at the centre of the scene. These outflows push gas toward the equatorial plane, forming a disc.
Astronomers suspect there is at least one other star interacting with the material cast off by the central dying star, creating the abnormal appearance of this planetary nebula.
In this image, the red areas represent cool molecular gas, for example, molecular hydrogen.
Credit: NASA, ESA, CSA, STScI

In Webb’s NIRCam (Near-Infrared Camera) view of the object, it’s readily apparent that this nebula is multi-polar. This means there are several different elliptical outflows jetting out either way from the centre. These outflows compress gas towards the equatorial plane and create a disc. Astronomers say this is evidence that there are likely at least two stars at the centre of this scene. Specifically, a companion star is interacting with an aging star that had already begun to shed some of its outer layers of gas and dust.

The central region of the planetary nebula glows from the hot stellar core, seen as a light blue hue in near-infrared light. The dark orange material, which is made up of gas and dust, follows pockets or open areas that appear dark blue. This clumpiness could be created when dense molecules formed while being shielded from hot radiation from the central star. There could also be a time element at play. Over thousands of years, inner fast winds could be ploughing through the halo cast off from the main star when it first started to lose mass.

colourful, mostly blue, image of mid-infrared light from a glowing cloud with a distorted, asymmetrical shape. A star at the centre of the image is a small point of pinkish-white light. The asymmetrical shape of the expanding cloud of gas and dust resembles paint splattered on the ground. The filaments of the expanding shells are wispy, and mostly white and blue. The shells appear as lobes that push gas toward the equatorial plane, forming a disc. A perfect circle of white-ish blue dust traces the outer edges of the shells. The background of the image is black and speckled with tiny bright stars and distant galaxies. — The mid-infrared view of planetary nebula NGC 6072 from the NASA/ESA/CSA James Webb Space Telescope shows expanding circular shells around the outflows from the dying central star, which astronomers suspect is that pinkish white dot at the centre of the image. The longer wavelengths captured by Webb’s MIRI (Mid-Infrared Instrument) highlight the dust being cast off by the central dying star.
In this image, the blue represents cool molecular gas seen in red in the image from Webb’s NIRCam (Near-Infrared Camera) due to colour mapping.
Credit: NASA, ESA, CSA, STScI

The longer wavelengths captured by Webb’s MIRI (Mid-Infrared Instrument) are highlighting dust, revealing the star researchers suspect could be central to this scene. It appears as a small pink-white dot in this image. Webb’s look in the mid-infrared wavelength also reveals concentric rings expanding from the central region, the most obvious circling just past the edges of the lobes.

This may be additional evidence of a secondary star at the centre of the scene hidden from our view. The secondary star, as it circles repeatedly around the original star, could have carved out rings of material in a spiral pattern as the main star was expelling mass during an earlier stage of its life.

The red areas in NIRCam and blue areas in MIRI both trace cool molecular gas (likely molecular hydrogen) while central regions trace hot ionized gas.

Planetary nebulae will remain a topic of study for astronomers using Webb who hope to learn more about the full life cycle of stars and how they impact their surrounding environments. As the star at the centre of a planetary nebula cools and fades, the nebula will gradually dissipate into the interstellar medium — contributing enriched material that helps form new stars and planetary systems, now containing those heavier elements.

Webb’s imaging of NGC 6072 opens the door to studying how the planetary nebulae with more complex shapes contribute to this process.

Webb image of NGC 6072 with compass arrows, scale bar, and colour key. It has a mostly red image of near-infrared light from a glowing cloud with a distorted, asymmetrical shape, illuminated from within by a bright central star. In the centre of this image, a light blue glow casts over areas of dark pockets that appear dark blue and are traced with orange material. It has a clumpy appearance. The shells become a deeper red with distance from the center. At the bottom right is a scale bar labeled .5 light-years. The length of the scale bar is about one fifth of the total image. At the bottom right are compass arrows indicating the orientation of the image on the sky. Below the image is a colour key showing which NIRCam filters were used to create the image and which visible-light colour is assigned to each filter. — This image of NGC 6072, captured by the James Webb Space Telescope’s NIRCam (Near-Infrared Camera), shows compass arrows, scale bar, and colour key for reference.
The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped to the direction arrows on a map of the ground (as seen from above). The scale bar is labeled in light-years, which is the distance that light travels in one Earth-year (it takes 0.5 years for light to travel a distance equal to the length of the scale bar). One light-year is equal to about 9.46 trillion kilometers. This image shows invisible near-infrared wavelengths of light that have been translated into visible-light colours. The colour key shows which NIRCam filters were used when collecting the light. The colour of each filter name is the visible light colour used to represent the infrared light that passes through that filter.
Credit: NASA, ESA, CSA, STScI

Press release from ESA Webb.

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Wilhelm Schickard invented the mechanical calculator 400 years ago

A letter from Tübingen universal scientist Wilhelm Schickard to the famous astronomer Johannes Kepler on September 20, 1623, documents the invention of the first mechanical calculator:

“Moreover, I have recently attempted the same by mechanical means as you have done mathematically, and constructed a machine consisting of eleven complete and six modified small wheels.”

With delicate lines, Schickard sketched the design of his invention.

Replica of Wilhelm Schickard’s calculator. Location: University of Tübingen Mueum. Credit: MUT/V. Marquardt

Using up to six-digit figures, the construction could undertake all types of basic calculation: addition, subtraction, multiplication and division. Its greatest feature however was the automatic carrying of tens, at which point a small bell apparently rang as the last digit changed from 9 to 0. Schickard was now able to calculate the movements of heavenly bodies faster and more easily than was possible manually.

The central element of the mechanical calculator was an adding machine with six cogwheels which could be used to set numbers from 0 to 9. This added up if rotated clockwise, while turning anticlockwise subtracted. For multiplication, Schickard integrated a system reminiscent of the calculating rods of Scottish scholar John Napier, and combined them with the cogs of the mechanical adder, which defined the multiplier. The numbers simply had to be set and the results could be read out – the machine did the actual calculating.

The Tübingen calculating machine was closely related chronologically to the revolution in natural sciences at the start of the 17^th century. The work of astronomers Tycho Brahe, Galileo Galilei and Johannes Kepler had shown that natural phenomena – such as the movement of the planets – could be precisely predicted through observation, measurement and calculation. The sciences were also being taken seriously and promoted in political circles, with many at that time believing that the future could also be foretold from the positions of heavenly bodies. However, the mathematical challenges were increasing with the ever more complex calculations involved in the still-young sciences. Yet undertaking calculations with large numbers is prone to mistakes.

“In particular when adding long series of numbers, Schickard’s calculating machine could have been a great relief, as it could help to avoid miscalculations,” explains Tübingen computer scientist, Professor Herbert Klaeren.

“Schickard’s construction contains the core elements of computer science,” says Professor Oliver Bringmann, speaker of the Department of Computer Science at the University of Tübingen. “It defines calculation rules and applies them in an automated process.” Calculating machines with greater capacity were not built until the 18^th century.

Constructing the machine and experimenting with it accompanied Schickard’s work at the University of Tübingen. In 1619 the theologian was appointed Professor of Hebrew and other biblical languages. He developed a study aid for his students consisting of rotating stacked discs with Hebraic verbs and endings to enable them to learn the complicated conjugations more easily. Even Isaac Newton had one. In 1631 Schickard was appointed to the Chair of Astronomy, Mathematics and Geodesics as the successor to astronomer and mathematician Michael Mästlin. Using a hand-held planetarium of his own invention, he showed the movements of the sun, the earth and the moon, and a conical star chart simplified identification of the constellations. As a school warden, he inspected Latin schools in Württemberg and surveyed the state while on his travels. From this data he drew far more precise maps than had previously been possible.

Johannes Kepler, who like Schickard studied at the University of Tübingen, became aware of his younger colleague as early as 1617. Kepler clearly recognized young Schickard’s powerful intellect and passion for mathematics at this time, and encouraged him to study science. From then on, Kepler and Schickard corresponded, and they met up again when Kepler returned to Württemberg in 1620 to assist his mother who was on trial for witchcraft. The astronomer valued Schickard’s skills as a craftsman and an artist, and engaged him to make copperplates and woodcuts for his revolutionary work “Harmonice mundi”, in which Kepler formulated the laws of planetary movements. Schickard for his part knew how much time Kepler spent calculating planetary orbits, and wanted to make the task easier for his friend.

Presentation of 20 euro commemorative coin and stamp

So Schickard commissioned the construction of a “calculating clock”, as he called it, by the craftsman-mechanic Johann Pfister, who built one model for Schickard in 1623 and later a second model intended for Kepler. However, Kepler’s model was destroyed by a fire in Pfister’s workshop.

Schickard’s life had a tragic end. In the early days of the Thirty Years’ War, the City of Tübingen escaped destruction by paying huge amounts of money. Yet once the battle of Nördlingen was lost in 1634, imperial troops were quartered in Tübingen and brought the plague with them. First, it took Schickard’s wife and three daughters. Schickard himself fell ill, but recovered. In October 1635 he caught the plague again, and this time died, just one day before his nine year old son.

Wilhelm Schickard invented the mechanical calculator 400 years ago. Portrait of Wilhelm Schickard from 1632. In his right hand he holds the hand-held planetarium he invented, in his left, a conical map of the moon’s orbit. Credit: MUT / V. Marquardt

Following the death of Schickard and his family in the Black Death, the knowledge of his calculating machine and Schickard’s own model were lost in the chaos of the Thirty Years’ War. Erroneously, historians credited the French philosopher Blaise Pascal with inventing the first mechanical calculator, some twenty years later. Much later, Schickard’s sketches resurfaced, and after the Second World War the machine was reconstructed at the University of Tübingen thereby proving its effectiveness. In 1960 it was presented in public. Today, there are replicas in the computer collection of the University of Tübingen and the Tübingen city museum, among other places.

On September 14, 2023, the University of Tübingen will be celebrating the 400^th anniversary of Schickard’s invention with a ceremony in the Neue Aula. At the event, the Federal Ministry of Finance together with the University will showcase a 20 euro commemorative coin and an 85 cent commemorative stamp in honor of Wilhelm Schickard and his invention. Afterward, the University of Tübingen’s Department of Computer Science will be holding a symposium on the theme “From the mechanical calculator to quantum computing”.

Press release from the University of Tübingen

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