Nine new open clusters found in the Sun's neighborhood

August 16, 2016 by Tomasz Nowakowski report
Distances and ages of the newly found clusters within 500 pc. (The new clusters are shown as black squares, whereas the MWSC clusters (Kharchenko et al. 2013) are shown as crosses. The open squares mark the age spread of the cluster RSG9. Credit: arXiv:1608.02704 [astro-ph.SR]

(Phys.org)—Astronomers from Heidelberg University in Germany and the Observatory of Strasbourg in France have detected nine new open star clusters within 1,500 light years from the sun. The discovery, presented in a paper published Aug. 9 on arXiv.org, improves our knowledge of star cluster population in the vicinity of our solar system.

Studying star clusters is crucial for our understanding of star formation and of the history of our Milky way galaxy. Open clusters, formed from the same giant molecular cloud, are groups of stars loosely gravitationally bound to each other. So far, more than 1,000 of them have been discovered within the Milky Way, and scientists are still looking for more, especially within the larger solar neighborhood, hoping to find a variety of these stellar groupings.

However, recent observations and studies have shown that old open clusters are very rare within about 3,000 from the sun. This under-density was subject of an investigation by a team of astronomers led by Siegfried Röser of the University of Heidelberg. The researchers have analyzed Tycho-2 and URAT1 astronomical catalogs in order to look for target objects.

Tycho-2 is an astrometric reference catalog containing positions and proper motions as well as two-color photometric data for the 2.5 million brightest stars in the sky. In order to test what proper motions, more precise than those of Tycho-2, can do for open studies, the scientists have also used the URAT1 catalog containing positional data on about 228 million stars with a magnitude ranging from 3.0 to 18.5.

"We derived proper motions from a combination of Tycho-2 with URAT1. (…) We detected nine hitherto unknown open clusters in the vicinity of the sun with ages between 70 million years and 1 billion years, and distances between 200 and 500 parsecs," the researchers wrote in the paper.

The newly found clusters were designated RSG1 to RSG9. According to the study, RSG2 is the nearest cluster, only 650 light years away, with the largest proper motion. The most distant is RSG7, located some 1,490 light years from the sun. With an age of about one billion years, RSG3 is the oldest cluster of all nine.

The team noted that it was not their intention to determine the most accurate astrophysical parameters of these clusters as they are expected to be provided by European Space Agency's (ESA) Gaia astrometric space observatory. Launched in 2013, Gaia aims to create the largest and most precise 3D space catalog ever made, containing approximately one billion astronomical objects. Röser and his colleagues rather wanted to prove that even a moderate progress in the precision of proper motions allows to reveal previously unknown open clusters in the solar neighborhood.

"Our results show that with highly precise proper motions and carefully selected search parameters it is still possible to reveal hitherto unknown even in the closer neighborhood of the sun up to 500 parsecs," the paper reads.

The scientists also underlined that the findings contribute substantially to our current knowledge of the nearby open cluster population, including old clusters.

"Although we could only search on 67 percent of the sky, our results increase the total number of clusters within 500 parsecs by 10 percent. (…) RSG3 adds one more cluster to this old cluster generation," the researchers concluded.

Explore further: Seven new embedded clusters detected in the Galactic halo

More information: Nine new open clusters within 500 pc from the Sun, arXiv:1608.02704 [astro-ph.SR] arxiv.org/abs/1608.02704

Abstract
One of the results of the Milky Way Star Clusters (MWSC) survey by Kharchenko et al. (2013) was the detection of a slight under-density of old (ca. 1 Gyr) clusters within the nearest kilo-parsec from the Sun. This under-density may be due to an ineffectiveness in the detection of larger structures with lower surface brightness. We report on our attempts to reveal such clusters. We derived proper motions from a combination of Tycho-2 with URAT1, and obtained a mean precision of about 1.4 mas/y per co-ordinate for 1.3 million stars north of -20 degree declination. We cut the sky into narrow proper motion slices and searched for spatial over-densities of stars in each slice. In optical and near-infrared colour-magnitude diagrams stars from over-densities were than examined to determine if they are compatible with isochrones of a cluster. We estimated the field star contamination using our data and the Besancon Galactic model.We detected 9 hitherto unknown open clusters in the vicinity of the Sun with ages between 70 Myr and 1 Gyr, and distances between 200 and 500 pc.

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Benni
1 / 5 (9) Aug 16, 2016
Nine new open clusters found in the Sun's neighborhood


Astronomers need to cease with publishing this kind of stuff, just shut the hell up about ti. As they keep observing more & more of this visible matter it is continuing to quell the enthusiasm for Envelopes of Dark Matter that Zwicky claimed surrounds all Spiral Galaxies such as ours.
RealityCheck
1 / 5 (6) Aug 16, 2016
Hi Benni. :)

Please stop slagging off Zwicky, mate. He only postulated ORDINARY then-undetected MATTER, not the EXOTIC/NON-ORDINARY imaginary stuff that later theoretical/mathematical astronomers/relativists turned it into. :)

I already reminded you that the ORDINARY matter being found now, in great abundances, is EXACTLY what Zwicky postulated. So he was SPOT ON.

So save your anger for those who turned Zwicky's most reasonable postulated ORDINARY matter into all sorts of IMAGINARY mathematical/philosophical 'stuff' to explain their own ignorance of what REAL stuff was actually 'out there' that is only recently being detected by newer telescopes....all via EM spectrum!

So, mate, please lay off Zwicky; it's not his fault. He was correct; and the latest ordinary matter finds prove him so. It's the later 'NON-EM DARK-MATTER-inventing' theoretical/mathematical cosmologists/relativists that have some serious apologizing to do TO Zwicky's memory!

Cheers. :)
RealityCheck
2.1 / 5 (7) Aug 16, 2016
PS: @ Benni.

Please also note that in the above article the stars were already known to be there. It was only improved study of their proper motions which 'discovered' that their proper motions were of the kind which showed they were interacting with each other gravitationally as if they were an 'open type' cluster of stars.

As far as I can tell, no 'new' stars/material was 'discovered', only 'new' system of motions as in open cluster by the stars already known to be there.

So don't use this article for your 'new ordinary dark matter discovery' arguments, mate! Cheers. :)
RealityCheck
1 / 5 (5) Aug 16, 2016
PPS: @ Benni.

Of course, it may be that there may be some stars of lesser magnitude which previous observations missed but which are now involved in the open cluster identified as above. I have not seen any info on that aspect yet. Let me know if you/anyone has any such info. Thanks. :)
Bigbangcon
1.4 / 5 (10) Aug 16, 2016
"However, recent observations and studies have shown that old open clusters are very rare within about 3000 light years from the sun."

Open clusters are VERY RARE everywhere in the universe, because these break up and dissipate with time. This discovery of the outward flow of galactic objects by Ambartsumian was the first blow to the idea of unidirectional condensation of matter to form galaxies after the so-called Big Bang. Arp's discordant redshift was the next. http://redshift.v...2MAL.pdf

The unbiased new findings of official physicists themselves are bringing them increasing nightmares both in the realm of astrophysics and particle physics. The fog and the fantasies of mathematical idealism are also rapidly dissipating like the open star clusters! How sad!
RNP
4.6 / 5 (9) Aug 17, 2016
This discovery of the outward flow of galactic objects by Ambartsumian was the first blow to the idea of unidirectional condensation of matter to form galaxies after the so-called Big Bang. Arp's discordant redshift was the next. http://redshift.v...2MAL.pdf

You claim this, but Ambartsumian would not have agreed with you. (He did a lot of work on star and galaxy formation in which he assumed the very model that you are condemning). Arp's "discordant redshift" has, time after time, been shown to be a statistical anomaly (an example of cosmic variance).

The unbiased new findings of official physicists themselves are bringing them increasing nightmares both in the realm of astrophysics and particle physics.....

What new findings? Why do you say "increasing nightmares" - we know more today today than we did yesterday, and will in all likelihood know more still tomorrow.

The fog and the fantasies.....

What DO you mean by that?
BongThePuffin
Aug 17, 2016
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