Familiar-Looking Messenger from Another Solar System
by Staff Writers
Tucson AZ (SPX) Nov 21, 2017
The visit of the interstellar interloper 1I/2017 U1, recently spotted streaking through the solar system, gives the people of Earth their first chance to study up close an object from another planetary system.
In a study carried out with the WIYN telescope at Kitt Peak National Observatory and the Nordic Optical Telescope in the Canary Islands, astronomers find that despite its foreign origins, U1 is familiar in appearance - its size, rotation, and color are similar to that of asteroids in our solar system. Its familiar appearance supports the long-held view that our solar system once ejected its own flotilla of such messengers out into interstellar space.
Discovered on 18 October 2017 as it sped away from the Sun, the interstellar interloper U1 was quickly recognized, from its hyperbolic orbit, to have originated outside the solar system. Its fortuitous close passage to Earth, first noticed by the Pan-STARRS telescope, attracted the attention of astronomers eager to take a close look at an object formed elsewhere in the galaxy.
In a sequence of images taken over 5 nights with the One Degree Imager on the 3.5-m WIYN telescope at Kitt Peak National Observatory and with the 2.5-m Nordic Optical Telescope on La Palma in the Canary Islands, U1 was found to be slightly red and to vary in brightness with an 8-hour period. Both properties are similar to those of asteroids in the inner solar system.
Like a Rotating Fire Extinguisher
"With such an elongated shape, U1 probably needs a little cohesive strength to hold it together. But that's not really unusual," remarked study coauthor Jayadev Rajagopal (National Optical Astronomy Observatory). Commenting on its size, rotation, and color, Rajagopal mused that, "the most remarkable thing about U1 is that, except for its shape, how familiar and physically unremarkable it is."
Seeing Our History in a Familiar Face
As the giant planets formed, they jostled leftover asteroids and comets into increasingly eccentric orbits. Some asteroids and comets impacted the inner planets leaving craters. Others are thought to have been ejected from the solar system entirely.
The pock-marked surfaces of the inner solar system help to verify this story. However, there has been no direct evidence to date that comets and asteroids were once ejected from the solar system. If planets form around other stars the same way they did in the solar system, many objects the size of U1 are predicted to be ejected in the process.
"U1 may provide the first direct evidence that planetary systems around other stars ejected objects as they formed," concluded Rajagopal.
Are Others Out There?
That perspective suggests that our solar system may, in fact, be flooded with interstellar interlopers that pass through the solar system undetected. The authors estimate that based on the properties of U1, there are about ten thousand U1-sized objects closer to the Sun than Neptune at any given time.
"Each one whizzes through the solar system in about 10 years," says Jewitt, "and every 10 years or so, we have a completely new bunch of these objects, a few of which we can hope to see."
Future surveys designed to detect moving objects, such as the wide, fast, deep survey to be carried out with the Large Synoptic Survey Telescope, are likely to discover more of these interlopers, giving us further opportunities to study objects from beyond the solar system.
"Interstellar Interloper 1I/2017 U1: Observations from the NOT and WIYN Telescopes," David Jewitt et al., 2017, submitted to Astrophysical Journal Letters
Paris (ESA) Nov 15, 2017
A temperate Earth-sized planet has been discovered only 11 light-years from the Solar System by a team using ESO's unique planet-hunting HARPS instrument. The new world has the designation Ross 128 b and is now the second-closest temperate planet to be detected after Proxima b. It is also the closest planet to be discovered orbiting an inactive red dwarf star, which may increase the likeli ... read more
National Optical Astronomy Observatory
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.