VVV CL001
{{Short description|One of the most metal poor globular clusters}}
{{Infobox globular cluster|name=VVVCL001|constellation=Sagittarius|dist_pc=8.22 kpc|dist_ly=26,800 ly|notes=One of the most metal poor globular clusters|age=11.9 gya|ra=17h 54m 37.17s|dec=-24° 4' 51.34"|image=Globular Cluster VVV CL001.jpg|caption=A image from the Vista Variables in the Via Lactea (VVV) survey showing VVV CL001 located inconspicuously to the left while UKS 1 is on the right}}
VVV CL001 is a globular cluster located around 8.22 kiloparsecs from Earth in the constellation of Sagittarius.{{Cite web |last=information@eso.org |title=VISTA view of the newly discovered globular cluster VVV CL001 and its brighter companion |url=https://www.eso.org/public/images/eso1141a/ |access-date=2025-06-12 |website=www.eso.org |language=fr}} It is the most metal poor globular cluster discovered around the Milky Way. {{Citation |last=Fernández-Trincado |first=José G. |title=VVV CL001: Likely the Most Metal-Poor Surviving Globular Cluster in the Inner Galaxy |date=2021-02-03 |url=http://arxiv.org/abs/2102.01088 |access-date=2025-06-12 |publisher=arXiv |doi=10.48550/arXiv.2102.01088 |id=arXiv:2102.01088 |last2=Minniti |first2=Dante |last3=Souza |first3=Stefano O. |last4=Beers |first4=Timothy C. |last5=Geisler |first5=Doug |last6=Bidin |first6=Christian Moni |last7=Villanova |first7=Sandro |last8=Majewski |first8=Steven R. |last9=Barbuy |first9=Beatriz}} It is an old globular cluster with an age of 11.9 billion years. VVV CL001 is likely an ancient relic that was left behind by a past galactic merger by a massive galaxy early in the evolution of the Milky Way galaxy. It has a mass of 1.5x10^5 solar masses.{{Cite web |title=VVV-CL001 |url=https://people.smp.uq.edu.au/HolgerBaumgardt/globular/fits/vvvcl001.html |access-date=2025-06-12 |website=people.smp.uq.edu.au}}
It may be in a physical binary with another globular cluster known as UKS 1 however it is still being decided if they are an actual binary or have similar radial velocity.{{Cite journal |last=Minniti |first=D. |last2=Hempel |first2=M. |last3=Toledo |first3=I. |last4=Ivanov |first4=V. D. |last5=Alonso-García |first5=J. |last6=Saito |first6=R. K. |last7=Catelan |first7=M. |last8=Geisler |first8=D. |last9=Jordán |first9=A. |last10=Borissova |first10=J. |last11=Zoccali |first11=M. |last12=Kurtev |first12=R. |last13=Carraro |first13=G. |last14=Barbuy |first14=B. |last15=Clariá |first15=J. |date=2011-03-01 |title=Discovery of VVV CL001 - A low-mass globular cluster next to UKS 1 in the direction of the Galactic bulge |url=https://www.aanda.org/articles/aa/abs/2011/03/aa15795-10/aa15795-10.html |journal=Astronomy & Astrophysics |language=en |volume=527 |pages=A81 |doi=10.1051/0004-6361/201015795 |issn=0004-6361}}
Discovery
File:Area of the Milky Way mapped by the VVV and VVVX surveys (eso2413g).jpg mapped by the VVV and VVVX surveys]]
VVV CL001 was discovered by using the VISTA Variables in the Via Lactea (VVV) survey. It has several aims such as resolving the three-dimensional structure of the Milky Way galaxy by precisely measuring the distribution of RR Lyrae, Cepheids, and red clump stars.{{Cite journal |last=Saito |first=R. K. |last2=Hempel |first2=M. |last3=Alonso-García |first3=J. |last4=Lucas |first4=P. W. |last5=Minniti |first5=D. |last6=Alonso |first6=S. |last7=Baravalle |first7=L. |last8=Borissova |first8=J. |last9=Caceres |first9=C. |last10=Chené |first10=A. N. |last11=Cross |first11=N. J. G. |last12=Duplancic |first12=F. |last13=Garro |first13=E. R. |last14=Gómez |first14=M. |last15=Ivanov |first15=V. D. |date=2024-09-01 |title=The VISTA Variables in the Vía Láctea extended (VVVX) ESO public survey: Completion of the observations and legacy |url=https://www.aanda.org/articles/aa/abs/2024/09/aa50584-24/aa50584-24.html |journal=Astronomy & Astrophysics |language=en |volume=689 |pages=A148 |doi=10.1051/0004-6361/202450584 |issn=0004-6361}} Another aim of the VVV survey is to accurately measure the physical parameters of known globular clusters and search for new ones. It was this which discovered VVV CL001.