Starship Asterisk*

[size=120][b]Heron Galaxy (NGC 5394-5)[/b][/size]
[url]https://www.astrobin.com/t64ynf/0/[/url]
Copyright: Steven Miller
[attachment=0]IBxnYE8oVwpf_16536x0_ieTZ0INm.jpg[/attachment]

[size=120][b]IC 5332[/b][/size]
[url]http://www.atacama-photographic-observatory.com/page_photo.php?id=243[/url]
Copyright: Thiery Demange, Richard Galli and Thomas Petit
[attachment=0]IC5332.jpg[/attachment]

[size=120][b]Abell 773 and Abell 782[/b][/size]
[url]https://www.astrobin.com/wiaxgg/[/url]
Copyright: Ronald Hedden
[attachment=0]a6shCe8DHPQ3_16536x0_k2WM-q9H.jpg[/attachment]

[size=120][b]M56[/b][/size]
[url]https://www.astrobin.com/nlh06o/[/url]
Copyright: Fabian Rodriguez Frustaglia
[attachment=0]PKOSU8OKmkZO_16536x0_IZ4pzqsL.jpg[/attachment]

[size=120][b]Jewel Box Cluster (NGC 4755)[/b][/size]
[url]https://www.astrobin.com/12d3vx/[/url]
Copyright: Alexandre Fagundes
[attachment=0]hbcwV4g7Jw1B_2560x0_esdlMP5Y.jpg[/attachment]

[size=120][b]M10[/b][/size]
[url]https://www.astrobin.com/v1xwcf/[/url]
Copyright: Pete Bouras
[attachment=0]1vKRlRGRVCrg_2560x0_iyBCSgTs.jpg[/attachment]

[size=120][b]M48[/b][/size]
[url]https://www.astrobin.com/0ygrb2/[/url]
Copyright: Uwe Deutermann
[attachment=0]viULTqcHgTH-_16536x0_ieTZ0INm.jpg[/attachment]

[size=120][b]Aurora[/b][/size]
[url]https://www.astrobin.com/dut25c/[/url]
Copyright: Julien Cadena
[attachment=0]23v1ZYefPC8j_16536x0_ieTZ0INm.jpg[/attachment]

[size=120][b]Sh2-73[/b][/size]
[url]http://www.astrosurf.com/ilizaso/orriak/3maila/Sh2-73-LBN105_FSQ_U16m.htm[/url]
Copyright: Iñaki Lizaso
[attachment=0]Sh2-73.jpg[/attachment]

[size=120][b]M17[/b][/size]
[url]https://www.astrobin.com/5u5axa/[/url]
Copyright: Patrick Chevalley
[attachment=0]O-ZpfhgoPXzq_2560x0_n1wMX-gx.jpg[/attachment]

[size=120][b]NGC 6946 and NGC 6939[/b][/size]
[url]https://www.astrobin.com/kxnhen/B/[/url]
Copyright: Chris Sullivan
[attachment=0]K7uyF8QxhSzH_16536x0_g1E1qxQB.jpg[/attachment]

[size=120][b]CTA 1 and NGC 40[/b][/size]
[url]https://www.astrobin.com/txrhgn/[/url]
Copyright: Rolf Dietrich
[attachment=0]uVa4HWE5-Jsj_16536x0_w70q2OVT.jpg[/attachment]

[size=120][b]Hu 2[/b][/size]
[url]https://www.astrobin.com/j4fkc8/[/url]
Copyright: Earle Waghorne
[attachment=0]EdjOnC9HREB-_16536x0_0BaKJj-0.jpg[/attachment]
In the sky, Hu 2 is located in the vicinity of the supernova remnant CTA 1.

[size=120][b]KinPau 1[/b][/size]
[url]https://www.astrobin.com/h8la3v/[/url]
Copyright: Sven Eklund
[attachment=0]ae-5XBD8nRnQ_16536x0_DNzvvtIX.jpg[/attachment]

[size=120][b]Murrell 1[/b][/size]
[url]https://www.astrobin.com/7xk1y1/[/url]
Copyright: Andrew Murrell
[attachment=0]HMrJ3kFdGSjN_16536x0_Rr9Vgg-0.jpg[/attachment]

[size=120][b]Longmore 18[/b][/size]
[url]https://members.pcug.org.au/~stevec/longmore18_STXL6303_2023.htm[/url]
Copyright: Steve Crouch
[attachment=0]longmore18.jpg[/attachment]

[quote=starsurfer post_id=339537 time=1717799056 user_id=137896]
[size=120][b]M37[/b][/size]
[url]https://www.astrobin.com/e90jkf/[/url]
Copyright: Antoine and Dalia Grelin
kkYsOQppC5W6_2560x0_qNFj77Wg.jpg
M37 is one of the few open clusters known to [url=https://arxiv.org/abs/2208.06101]contain a planetary nebula[/url], which is catalogued as IPHASX J055226.2+323724.
[/quote]

Amazing! When I first saw the pink cloud in M37, I just couldn't understand what it was. It's a planetary nebula! It is very large, it is very old (the oldest known planetary?), it sits in a ~500 million year old cluster, and the progenitor star had a mass of about ∼2.8 M[sub]☉[/sub], which would make it a star of late type B (B8 or B9).

The huge planetary nebula in M37 has been a planetary nebula for a long time (a million years???), but its presence in this cluster still tells us something about how long a late type B star with a mass of some 2.8 M[sub]☉[/sub] can be expected to live, its red gianthood included.

Ann

[size=120][b]NGC 4449[/b][/size]
[url]https://www.astrobin.com/ltlyep/[/url]
Copyright: Timothy Prospero
[attachment=0]KVMBTES7XVfQ_16536x0_17tICBCa.jpg[/attachment]

[size=120][b]M81[/b][/size]
[url]https://www.astrobin.com/xzrgxm/[/url]
Copyright: Ronald Hedden
[attachment=0]QEzW7sxeDjZK_16536x0_dnBRd2GS.jpg[/attachment]

[size=120][b]NGC 4725[/b][/size]
[url]https://www.astrobin.com/a0093f/[/url]
Copyright: Andre Vilhena
[attachment=0]MrLvFVn_YVIy_16536x0_rjxI6NUP.jpg[/attachment]

[size=120][b]NGC 5907[/b][/size]
[url]https://www.astrobin.com/ybhuyp/[/url]
Copyright: Michael Schmidt
[attachment=0]KLaVfz2MfNFS_16536x0_ieTZ0INm.jpg[/attachment]

[size=120][b]NGC 4945[/b][/size]
[url]https://www.astrobin.com/6hk1n6/[/url]
Copyright: Bruno Rota Sargi
[attachment=0]dkB88vt3JG0k_16536x0_ieTZ0INm.jpg[/attachment]

[size=120][b]NGC 7129 and G107.0+9.0[/b][/size]
[url]https://www.astrobin.com/diwu7q/[/url]
Copyright: Nicolas Martino
[attachment=0]qmVOdNGvFGv4_16536x0_ieTZ0INm.jpg[/attachment]
A scientific paper about G107.0+9.0 can be found [url=https://arxiv.org/abs/2008.05620]here[/url].

[size=120][b]IC 4601[/b][/size]
[url]http://www.astrostudio.at/1_Deep%20Sky%20Objects.php?img=images/1_Deep%20Sky%20Objects/293_IC4601.jpg[/url]
Copyright: Gerald Rhemann
[attachment=0]IC4601.jpg[/attachment]

[size=120][b]M37[/b][/size]
[url]https://www.astrobin.com/e90jkf/[/url]
Copyright: Antoine and Dalia Grelin
[attachment=0]kkYsOQppC5W6_2560x0_qNFj77Wg.jpg[/attachment]
M37 is one of the few open clusters known to [url=https://arxiv.org/abs/2208.06101]contain a planetary nebula[/url], which is catalogued as IPHASX J055226.2+323724.