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Messier 93 – the NGC 2447 Open Star Cluster

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Messier 93 – the NGC 2447 Open Star Cluster

Welcome again to Messier Monday! Right this moment, we proceed in our tribute to our expensive good friend, Tammy Plotner, by wanting on the globular cluster often called Messier 92!

Throughout the 18th century, famed French astronomer Charles Messier observed the presence of a number of “nebulous objects” whereas surveying the evening sky. Initially mistaking these objects for comets, he started to catalog them in order that others wouldn’t make the identical mistake. Right this moment, the ensuing record (often called the Messier Catalog) consists of over 100 objects and is among the most influential catalogs of Deep House Objects.

One in all these objects is named Messier 93, an open star cluster positioned roughly Three,600 light-years from Earth within the constellation Puppis. The cluster measures 20 to 25 light-years in diameter and is positioned in the identical space of the sky as Sirius. Mixed with its luminosity, which makes it observable on a transparent evening or with binoculars, this star cluster is comparatively straightforward to search out.


Hanging out in house some Three,600 light-years away and masking an expanse of practically 25 light-years, M93’s brightest stars are kind B9 blue giants of kind B9 with an estimated age of roughly 100 million years. However blue big stars aren’t the one kind you’ll discover right here. There are at the very least Three purple big stars as effectively. As S. Hamdani (et al) mentioned in a 2000 study:

“Chemical abundances of about fifteen components from oxygen to europium are measured in seven purple giants of the 2 open clusters NGC 2360 and NGC 2447. The efficient temperatures of the giants are decided spectroscopically by making the most of their recognized lots (~2 Mo in NGC 2360 and ~Three Mo in NGC 2447) and bolometric magnitudes. The typical iron abundances we receive for the 2 clusters are [Fe/H]=Zero.07 for NGC 2360 and [Fe/H]=Zero.03 for NGC 2447. Evolutionary stellar mannequin calculations are carried out within the mass vary 1-Four Mo as a way to analyze the floor Na and O abundances predicted after the primary dredge-up. The sodium abundance exhibits a effectively outlined correlation with stellar mass within the 2-Three Mo vary.

The settlement between our Na abundance determinations in NGC 2360 and our mannequin predictions at 2 Mo is superb. In distinction, the overabundance in one of many three stars in NGC 2447 exceeds that predicted at Three Mo by ~Zero.08 dex, which is critical in comparison with the observational error bars. The consequences of core overshooting, convection prescription, metallicity and nuclear response charges on the Na floor predictions of our fashions are investigated. An oxygen deficiency relative to iron by Zero.2 dex is measured in our stars, in disagreement with our mannequin predictions. Assuming that the Solar is Zero.1-Zero.Three dex enriched in oxygen relative to neighbor stars might clarify the discrepancy.”

m93atlast-505x580 Messier 93 - the NGC 2447 Open Star Cluster
Atlas mosaic picture obtained as a part of the Two Micron All Sky Survey (2MASS). Credit score: College of Massachusetts/IPAC/Caltech/NASA/NSS

So why are research just like the 2MASS undertaking so necessary relating to one thing like a open star cluster? Mentioned H.C. Lee in a 2005 study:

“We use Two Micron All-Sky Survey (2MASS) to check open clusters within the photo voltaic neighborhood. Dias (2003) compiles a catalogue of optical open clusters from literature. The error and consistency are tough to estimate attributable to completely different observational methods and sources. With a view to examine the impact of dynamical evolution and galactic location on open clusters, we use radial density profile from 2MASS level supply catalogue to reestimate the dimensions of clusters. We additionally talk about the distinction between completely different strategies. We discover that the sizes of previous open clusters are bigger, and the quantity densities of them are smaller. Previous open clusters are distributed greater from the disk. We work out the principle sequence luminosity operate and important sequence mass operate of 17 open clusters. We don’t discover the relation between age and luminosity operate and mass operate. We conclude that within the contest of important sequence luminosity operate and mass operate, 2MASS information is appropriate for clusters inside 2 kpc from the solar and age lower than Three×10 eight yr solely. Furthermore, we discover that an fascinating outcome, the ability index of field-star luminosity features on completely different areas are very related, the common worth is Zero.336±Zero.01″

Historical past of Remark:

Found on March 20th, 1781, by Charles Messier and logged as: “Cluster of small stars, with out nebulosity, between the Better Canine [Canis Major] and the prow of the ship [Puppis of Argo Navis].”, M93 would start the astronomy profession of 1 very particular woman – Caroline Herschel.

On February 26, 1783, Caroline Herschel did one thing no different lady had achieved earlier than her… used her personal telescope to positioned a deep house object and start her personal catalog of observations. In her notes, she wrote:

“Nebula, about 1 1/Four deg north previous the intense star within the Ship [or more exactly] previous the first Navis [Puppis] in direction of 23 Canis majoris. My Brother examined it with [magnification] 460 and located not lower than 20 stars, with 227 above 40. with a compound eyepiece maybe 100 and 150 very stunning, nothing nebulous amongst them. Messier has it not.”

Though Charles Messier will get the total credit score for discovery and logging M93, take pleasure in this vibrant and exquisite cluster of stars because the “Opening Night time” of the primary woman of astronomy!

m93atlast-505x580 Messier 93 - the NGC 2447 Open Star Cluster
The placement of Messier 93 within the constellation Puppis. Credit score: IAU and Sky & Telescope journal (Roger Sinnott & Rick Fienberg)

Finding Messier 93:

Because of what looks as if the brighter stars of the winter constellations, M93 isn’t too arduous to search out… All you want to do is get Sirius! Barely lower than a fist-width southeast of one of many brightest stars within the evening sky, you’ll spy fainter north/south pairing of Omicron 1 and Omicron 2 Canis Majoris. M93 is positioned alongside the similar parallel (declination).

Now proceed your starhop one other fist-width (10 levels) to Xi Puppis and also you’ll catch it to the north. Very vibrant and resolvable, M93 works effectively with any dimension optics (binoculars or telescopes) and makes a splendid city goal and holds up very effectively to “moon air pollution”!

And listed below are the fast information on this Messier Object that will help you get began:

Object Identify: Messier 93
Various Designations: M93, NGC 2447
Object Kind: Kind g Open Star Cluster
Constellation: Puppis
Proper Ascension: 07 : 44.6 (h:m)
Declination: -23 : 52 (deg:m)
Distance: Three.6 (kly)
Visible Brightness: 6.Zero (magazine)
Obvious Dimension: 22.Zero (arc min)

Now we have written many fascinating articles about Messier Objects right here at Universe Right this moment. Right here’s Tammy Plotner’s Introduction to the Messier Objects, M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.

Be to certain to take a look at our full Messier Catalog. And for extra info, take a look at the SEDS Messier Database.


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