KIM 3: AN ULTRA-FAINT STAR CLUSTER in the CONSTELLATION of CENTAURUS

Dongwon Kim; Helmut Jerjen; Dougal Mackey; Gary S. Da Costa; Antonino P. Milone

doi:10.3847/0004-637X/820/2/119

KIM 3: AN ULTRA-FAINT STAR CLUSTER in the CONSTELLATION of CENTAURUS

Dongwon Kim, Helmut Jerjen, Dougal Mackey, Gary S. Da Costa, Antonino P. Milone

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40 Citations (Scopus)

Abstract

We report the discovery of an ultra-faint star cluster in the constellation of Centaurus. This new stellar system, Kim 3, features a half-light radius of r_h= 2.29_-0.52^+1.28 pc and a total luminosity of M_V=+0.7 ± 0.3. Approximately 26 stars are identified as candidate member stars down to four magnitudes below the main-sequence turn-off, which makes Kim 3 the least luminous star cluster known to date. The compact physical size and extreme low luminosity place it close to faint star clusters in the size-luminosity plane. The stellar population of Kim 3 appears to be relatively young (9.5_-1.7^+3.0 Gyr) and metal-poor ([Fe/H] = -1.6_-0.30^+0.45) at a heliocentric distance of 15.14_-0.28^+1.00 kpc. The cluster lacks a well-defined center, and a small but prominent group of stars consistent with the Kim 3 isochrone is present approximately 9.7 pc in projection south of the cluster center. Both are signs of the cluster being in the final stage of tidal disruption.

Original language	English
Article number	119
Journal	Astrophysical Journal
Volume	820
Issue number	2
DOIs	https://doi.org/10.3847/0004-637X/820/2/119
Publication status	Published - 1 Apr 2016

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title = "KIM 3: AN ULTRA-FAINT STAR CLUSTER in the CONSTELLATION of CENTAURUS",

abstract = "We report the discovery of an ultra-faint star cluster in the constellation of Centaurus. This new stellar system, Kim 3, features a half-light radius of rh= 2.29-0.52+1.28 pc and a total luminosity of MV=+0.7 ± 0.3. Approximately 26 stars are identified as candidate member stars down to four magnitudes below the main-sequence turn-off, which makes Kim 3 the least luminous star cluster known to date. The compact physical size and extreme low luminosity place it close to faint star clusters in the size-luminosity plane. The stellar population of Kim 3 appears to be relatively young (9.5-1.7+3.0 Gyr) and metal-poor ([Fe/H] = -1.6-0.30+0.45) at a heliocentric distance of 15.14-0.28+1.00 kpc. The cluster lacks a well-defined center, and a small but prominent group of stars consistent with the Kim 3 isochrone is present approximately 9.7 pc in projection south of the cluster center. Both are signs of the cluster being in the final stage of tidal disruption.",

keywords = "Galaxy: halo, globular clusters: general, globular clusters: individual (Kim 3)",

author = "Dongwon Kim and Helmut Jerjen and Dougal Mackey and {Da Costa}, {Gary S.} and Milone, {Antonino P.}",

year = "2016",

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doi = "10.3847/0004-637X/820/2/119",

language = "English",

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T2 - AN ULTRA-FAINT STAR CLUSTER in the CONSTELLATION of CENTAURUS

AU - Kim, Dongwon

AU - Jerjen, Helmut

AU - Mackey, Dougal

AU - Da Costa, Gary S.

AU - Milone, Antonino P.

PY - 2016/4/1

Y1 - 2016/4/1

N2 - We report the discovery of an ultra-faint star cluster in the constellation of Centaurus. This new stellar system, Kim 3, features a half-light radius of rh= 2.29-0.52+1.28 pc and a total luminosity of MV=+0.7 ± 0.3. Approximately 26 stars are identified as candidate member stars down to four magnitudes below the main-sequence turn-off, which makes Kim 3 the least luminous star cluster known to date. The compact physical size and extreme low luminosity place it close to faint star clusters in the size-luminosity plane. The stellar population of Kim 3 appears to be relatively young (9.5-1.7+3.0 Gyr) and metal-poor ([Fe/H] = -1.6-0.30+0.45) at a heliocentric distance of 15.14-0.28+1.00 kpc. The cluster lacks a well-defined center, and a small but prominent group of stars consistent with the Kim 3 isochrone is present approximately 9.7 pc in projection south of the cluster center. Both are signs of the cluster being in the final stage of tidal disruption.

AB - We report the discovery of an ultra-faint star cluster in the constellation of Centaurus. This new stellar system, Kim 3, features a half-light radius of rh= 2.29-0.52+1.28 pc and a total luminosity of MV=+0.7 ± 0.3. Approximately 26 stars are identified as candidate member stars down to four magnitudes below the main-sequence turn-off, which makes Kim 3 the least luminous star cluster known to date. The compact physical size and extreme low luminosity place it close to faint star clusters in the size-luminosity plane. The stellar population of Kim 3 appears to be relatively young (9.5-1.7+3.0 Gyr) and metal-poor ([Fe/H] = -1.6-0.30+0.45) at a heliocentric distance of 15.14-0.28+1.00 kpc. The cluster lacks a well-defined center, and a small but prominent group of stars consistent with the Kim 3 isochrone is present approximately 9.7 pc in projection south of the cluster center. Both are signs of the cluster being in the final stage of tidal disruption.

KW - Galaxy: halo

KW - globular clusters: general

KW - globular clusters: individual (Kim 3)

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DO - 10.3847/0004-637X/820/2/119

M3 - Article

SN - 0004-637X

VL - 820

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 119

ER -

KIM 3: AN ULTRA-FAINT STAR CLUSTER in the CONSTELLATION of CENTAURUS

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