Amateur Astronomer Discovers New Moon of Jupiter

The newbie astronomer who final year recovered four lost Jovian moons has turn into the primary newbie to find a beforehand unknown moon. Kai Ly reported the invention to the Minor Planet Mailing List on June thirtieth and has submitted it for publication as a Minor Planet Electronic Circular.

Ly’s quest was a spin-off of their earlier identification of pre-recovery photographs of lately found Jovian moons together with Valetudo, Ersa, and Pandia whereas analyzing knowledge taken in 2003 with the three.6-meter Canada-France-Hawaii Telescope (CFHT).  David Jewitt and Scott Sheppard (University of Hawai‘i) had led a group that used these images to discover 23 new moons. The images remain available online, and Ly thought that more undiscovered moons might be hiding in the 2003 data set.

Jupiter moon orbits
Jupiter has 79 moons acknowledged by the International Astronomical Union’s Minor Planet Center, but an amateur astronomer has just discovered another one (not shown here). Most of the planet’s prograde moons (purple, blue) orbit relatively close to Jupiter, while its retrograde moons (red) orbit farther out. One exceptions is Valetudo (green), a prograde-moving body discovered in 2018 that’s far out.
Carnegie Inst. for Science / Roberto Molar Candanosa

After planning their search in May, Ly in early June started examining images taken in February 2003, when Jupiter was at opposition and its moons were brightest. They examined three survey images covering the same region of the sky at different times on the night of February 24th and found three potential moons moving at 13 to 21 arcseconds per hour during the night.

Ly could not recover two of the potential moons on other nights, but did find the third, temporarily designated EJc0061, on survey observations on February 25 to 27, and on images taken with the Subaru Telescope on February 5 and 6. That established a 22-day arc that suggested the object was bound to Jupiter. 

Ly thus had enough information to trace the moon’s orbit on survey photographs from March 12 to April 30. “From there on, the orbit and ephemeris quality was decent enough for me to begin searching observations beyond 2003,” Ly says. They discovered the moon close to its predicted place in later photographs from the Subaru, CFHT, and Cerro Tololo Inter-American Observatory taken by means of early 2018. The faint moon ranges from  magnitude 23.2 to 23.5.

The finish outcome was an arc of 76 observations over 15.26 years (5,574 days), sufficient for Ly to contemplate its orbit well-secured for many years. The knowledge observe the moon — provisionally designated S/2003 J 24 pending publication — by means of practically eight 1.9-year orbits of Jupiter, says David Tholen (University of Hawai‘i), more than enough to show it’s a moon. Tholen has not checked the images, but says the evidence seems solid: “It would be nearly impossible for artifacts to fit a Jovicentric orbit over so many different nights using different cameras.” 

Jupiter, Ganymede, Europa and double shadows, March 25, 2019
Ganymede and Europa, two of Jupiter’s large Galilean moons, were both casting their shadows onto the planet when Damian Peach took this image (south is up). Newly discovered moons are much farther out and much smaller, and thus much harder to find.

“I’m proud to say that that is the primary planetary moon found by an newbie astronomer!” says Ly. But in any other case, they admit, “it’s just a typical member of the retrograde Carme group.” This group consists of 22 different small moons orbiting Jupiter in the other way of its spin with intervals of round two years. Their orbits are comparable sufficient to counsel they have been all fragments from a single impression. They’re most likely chips off Carme, the primary of the group to be found and at 45 kilometers throughout, by far the most important.

Such small retrograde Jovian moons might have lots of firm awaiting discovery. Last year, Edward Ashton, Matthew Beaudoin, and Brett J. Gladman (University of British Columbia, Canada) noticed some 4 dozen objects as small as 800 meters throughout that seemed to be orbiting Jupiter. They didn’t observe them lengthy sufficient to show the objects have been Jovian moons, however from their preliminary observations, they steered that Jupiter could have some 600 satellites no less than 800 meters in diameter. The improvement of larger and extra delicate telescopes will create room for brand spanking new discoveries, Tholen says.

Carme (moon)
Near-infrared observations present Jupiter’s moon Carme, the most important of the Carme group of retrograde satellites. The ultimate body reveals a composite of all photographs stacked to visibly present the moon within the middle.
IPAC Infrared Science Archive / NASA / JPL-Caltech

Ly describes their moon-hunting as “a summer hobby before I return to school.” They hope to seek out extra, however with extra knowledge than they will course of by themselves from the  February 2003 observations alone, they determined to publicize their outcomes to boost curiosity.

Amateur Sam Deen is “quite impressed” with Ly’s accomplishment. He provides that when observatories submit survey knowledge overtly, it creates extra alternatives for amateurs to make discoveries. “The main obstacle is just getting to know what you’re doing and having the tolerance to go looking through the data for hours before turning up anything worthwhile,” he says.

Software and companies can assist in decoding the outcomes, together with the Find_Orb orbit determination software, the interactive Aladin Sky Atlas, the Minor Planet Center‘s many companies, and the Canadian Astronomical Data Center’s Solar System Object Image Search. The discipline is open for newbie astronomers to make their very own discoveries.


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