It is currently Tue, 04-08-20, 14:26 GMT

All times are UTC

Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Wed, 15-04-20, 16:05 GMT 

Joined: Wed, 05-12-18, 22:11 GMT
Posts: 19

I'm working on adding some globular clusters from the Magellanic Cloud. First one I'm doing is Hodge 11.

Globular "Hodge 11:ESO 57-76:KMHK 1700:LW 437"
   RA               6.23970  # [hours]
   Dec            -69.84858  # [degrees]
   Distance       1.631e+05  # [ly]
   Radius                64  # [ly], mu25 Isophote
   CoreRadius         0.250  # [arcmin]
   KingConcentration   1.09  # c = log10(r_t/r_c)
   AbsMag           -6.5649  # [V mags]
   InfoURL  " 11"

I'm reasonably confident that I have most of the parameters correct. I got the CoreRadius and KingConcentration parameters from Table 3 of Lanzoni et al. (2019).

I am the least confident about my Radius parameter. I got it by using the angular size listed on SIMBAD, but by looking at the references, I couldn't really tell whether it was the mu25 isophote diameter. I heard somewhere that the mu25 isophote is a standard for measuring the diameters of objects, so is it okay to use the diameter listed on SIMBAD?

Thanks in advance,

PostPosted: Wed, 15-04-20, 20:09 GMT 
Site Admin
User avatar

Joined: Fri, 31-08-07, 7:01 GMT
Posts: 4675
Location: Hamburg, Germany
Hi Luke,

from my original 2008 work on globular clusters for Celestia

[Click on image to make it better readable:]
Screenshot_20200415_214439.png [ 35.68 KiB | Viewed 561 times ]

and now the missing definition
Screenshot_20200415_214524.png [ 49.67 KiB | Viewed 561 times ]



PostPosted: Thu, 16-04-20, 22:47 GMT 

Joined: Wed, 05-12-18, 22:11 GMT
Posts: 19
Hi, thanks for the response,

I did come across those two posts of yours ;) Unfortunately, the image comparison of M4 with the moon is now gone. But that's fine, I just did a comparison of my own using Celestia:

M4-moon-comparison.png [ 429.93 KiB | Viewed 543 times ]

Unfortunately, my confusion about the mu25 isophote remains; specifically, where to find it. In the literature, I've found apparent diameters for star clusters, but rarely do they explicitly say whether it's the mu25 isophote or some other isophote. What do I do in that scenario?

Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC

Who is online

Users browsing this forum: No registered users and 2 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group