Quote:

---

JaFu 2 (diameter of 5" = 0.22 pc) in NGC 6441 is very likely a cluster member, having similar velocity (37 km/s), and extinction (E_B-V=0.4), in addition to being close to the cluster center (37").

---

Quote:

---

that the classification of NGC 6441 into one or the other of the usual Oosterhoff groups is difficult. The long periods of the RRab stars and the relatively large proportion of c-type pulsators are more typical of Oosterhoff II than Oosterhoff I systems, although we again note that 〈Pab〉 is unusually large even for Oosterhoff II. In contrast, the mean luminosity of the NGC 6441 RRc stars, as found by applying the Simon & Clement (1993a, 1993b) method (see § 5.1), is consistent with values found in Oosterhoff I clusters such as M3.

---

Quote:

---

NGC 6441 stands out as one of the more unique globular clusters of our Galaxy. NGC 6441 is confirmed to be a metal-rich globular cluster exhibiting an unusual HB morphology. (and) NGC 6441 was shown to stand apart from other Galactic globular clusters in that it does not fit in the Oosterhoff classification scheme. The mean periods of the RRab stars in the cluster are as long as or even longer than the typical, more metal-poor, Oosterhoff type II clusters. This contradiction in the trend of increasing period with decreasing metallicity for a given amplitude implies that the metallicity-luminosity relationship for RRLs is not universal—if, in fact, the RRLs in NGC 6441 do share the cluster's relatively high overall metallicity.

---

So, again, I have to thanks for bringing up this globular and allowing me the opportunity to increase my own understanding of the many wonders that this object holds. That is one thing I love about this hobby, the opportunity to learn something everytime I research an object I or someone else has observed and to find out some interesting facts about the object from the scientific community.

Here is a link to the second article incase someone wants it in PDF instead of the HTML I used: HTML or PDF Article

Edit: If your looking for planetary nebula's to view here is a list of summer objects: Planetary Nebula Obervers Guide BTW you can click on the home on the top (horrible midi music) and then go to the left and find seasonal PN's and get more by season or download his database.

--------------------
Jay in Utah
---------------------------
Location: Lat: 40.514N Long: -112.032W

Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth.
— Ptolemy, c.150 AD



My Blog

Edited by JayinUT (07/03/09 11:55 AM)

Post Extras