Starship Asterisk*

[quote=bystander post_id=330379 time=1681384803 user_id=112005]
[quote=De58te post_id=330378 time=1681384423 user_id=141631]
If this globular cluster, pictured, is considered 'mostly stealthy', I can't wait for you to show me a globular cluster that is considered a 'big showoff.'
[/quote]
It's the Lynx constellation, not the globular cluster, that is "mostly stealthy". Although, I must admit, I don't know why that is, either.
[/quote]

From the [url=http://en.wikipedia.org/wiki/Lynx_%28constellation%29]Lynx[/url] link at Wikipedia:

[quote]Naming it Lynx because of its faintness, he challenged future stargazers to see it, declaring that only the lynx-eyed (those with good sight) would have been able to recognize it[/quote]

[quote="Roger Venable" post_id=330382 time=1681390827]
You may notice blue stars scattered throughout this globular cluster. Since globulars are very old, the presence of blue stars needed an explanation, which astronomers figured out: some of the old stars sometimes collide in the densely populated central regions, resulting in a hotter, blue star. These are called "blue stragglers". NGC 2419 has more blue stragglers than most globulars and they are less centrally located, and astronomers consider this to be interesting regarding the evolution of this particular cluster. See, for example, https://iopscience.iop.org/article/10.1086/588462/fulltext/74121.text.html .
[/quote]


[float=left][attachment=1]M55 blue stragglers and turnoff point.png[/attachment][c][size=85][color=#0040FF]M55 Color Magnitude Diagram
B.J. Mochejska, J. Kaluzny, 1m Swope Telescope[/color][/size][/c][/float][float=right][img3="Color magnitude diagram for NGC 2419. Note the well-populated blue straggler branch. However, most of the blue stars in NGC 2419 belong to the horizontal branch. Credit: E. Dalessandro et al."]https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0004-637X/681/1/311/revision1/medium-fg3.gif?AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&Expires=1681995023&Signature=hBpmEYWTD0rETHCmY5hlKwPrArQ%3D[/img3][/float]
[clear][/clear]


And if you can't find the blue stragglers...


[attachment=0]Blue straggler stars in NGC 2419 Dalessandro et al.png[/attachment]


Ann

You may notice blue stars scattered throughout this globular cluster. Since globulars are very old, the presence of blue stars needed an explanation, which astronomers figured out: some of the old stars sometimes collide in the densely populated central regions, resulting in a hotter, blue star. These are called "blue stragglers". NGC 2419 has more blue stragglers than most globulars and they are less centrally located, and astronomers consider this to be interesting regarding the evolution of this particular cluster. See, for example, https://iopscience.iop.org/article/10.1086/588462/fulltext/74121.text.html .

Is it globular?
How come we see a ring in the place of a dense core?
[hide][attachment=1]hubble_ngc2419_potw1908a-.jpg[/attachment]
[attachment=0]hubble_ngc2419_potw1908a[1].jpg[/attachment][/hide]
[imghover=https://asterisk.apod.com/download/file.php?id=47223&mode=view]https://asterisk.apod.com/download/file.php?id=47224&mode=view[/imghover]

[quote=De58te post_id=330378 time=1681384423 user_id=141631]
If this globular cluster, pictured, is considered 'mostly stealthy', I can't wait for you to show me a globular cluster that is considered a 'big showoff.'
[/quote]
It's the Lynx constellation, not the globular cluster, that is "mostly stealthy". Although, I must admit, I don't know why that is, either.

If this globular cluster, pictured, is considered 'mostly stealthy', I can't wait for you to show me a globular cluster that is considered a 'big showoff.'

[url=https://apod.nasa.gov/apod/ap230413.html] [img]https://apod.nasa.gov/apod/calendar/S_230413.jpg[/img] [size=150]NGC 2419: Intergalactic Wanderer[/size][/url]

[b] Explanation: [/b] Stars of the globular cluster NGC 2419 are packed into this [url=https://www.nasa.gov/image-feature/goddard/2023/hubble-spies-a-multi-generational-cluster]Hubble Space Telescope[/url] [url=https://esahubble.org/images/potw1908a/]field of view[/url] toward the mostly stealthy constellation [url=http://en.wikipedia.org/wiki/Lynx_%28constellation%29]Lynx[/url]. The two brighter spiky stars near the edge of the frame are within our own galaxy. [url=http://messier.seds.org/xtra/ngc/n2419.html]NGC 2419[/url] itself is remote though, some 300,000 light-years away. In comparison, the Milky Way's satellite galaxy, the [url=https://apod.nasa.gov/apod/ap130528.html]Large Magellanic Cloud[/url], is only about 160,000 light-years distant. Roughly similar to other large globular star clusters like [url=https://apod.nasa.gov/apod/ap140529.html]Omega Centauri[/url], NGC 2419 is intrinsically bright, but appears faint because it is so far away. Its extreme distance makes it difficult to [url=https://arxiv.org/abs/1902.01416]study[/url] and compare its properties with other globular clusters that roam the halo of our Milky Way galaxy. Sometimes called "the Intergalactic Wanderer", [url=http://arxiv.org/abs/1310.4499]NGC 2419[/url] really does seem to have come from beyond the Milky Way. [url=https://ui.adsabs.harvard.edu/abs/2017A%26A...598L...9M/abstract]Measurements[/url] of the cluster's motion through space suggest it once belonged to the [url=https://en.wikipedia.org/wiki/Sagittarius_Dwarf_Spheroidal_Galaxy]Sagittarius dwarf spheroidal galaxy[/url], another small satellite galaxy being disrupted by repeated encounters with the much larger Milky Way.


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