TY - JOUR
T1 - Discovery of the first symbiotic star in NGC 6822
AU - Kniazev, Alexei Y.
AU - Väisänen, Petri
AU - Whitelock, Patricia A.
AU - Menzies, John W.
AU - Feast, Michael W.
AU - Grebel, Eva K.
AU - Buckley, David A.H.
AU - Hashimoto, Yas
AU - Loaring, Nicola
AU - Romero-Colmenero, Encarni
AU - Sefako, Ramotholo
AU - Burgh, Eric B.
AU - Nordsieck, Kenneth
PY - 2009/5
Y1 - 2009/5
N2 - We report the discovery of the first symbiotic star (V = 21.6, K S = 15.8 mag) in the Local Group dwarf irregular galaxy NGC 6822. This star was identified during a spectral survey of Hα emission-line objects using the Southern African Large Telescope during its performance-verification phase. The observed strong emission lines of H i and He ii suggest a high electron density and T* < 130 000 K for the hot companion. The infrared colours allow us to classify this object as an S-type symbiotic star, comprising a red giant losing mass to a compact companion. The red giant is an asymptotic giant branch (AGB) carbon star, and a semiregular variable, pulsating in the first overtone with a period of 142 d. Its bolometric magnitude is Mbol = -4.4 mag. We review what is known about the luminosities of extragalactic symbiotic stars, showing that most, possibly all, contain AGB stars. We suggest that a much larger fraction of Galactic symbiotic stars may contain AGB stars than was previously realized.
AB - We report the discovery of the first symbiotic star (V = 21.6, K S = 15.8 mag) in the Local Group dwarf irregular galaxy NGC 6822. This star was identified during a spectral survey of Hα emission-line objects using the Southern African Large Telescope during its performance-verification phase. The observed strong emission lines of H i and He ii suggest a high electron density and T* < 130 000 K for the hot companion. The infrared colours allow us to classify this object as an S-type symbiotic star, comprising a red giant losing mass to a compact companion. The red giant is an asymptotic giant branch (AGB) carbon star, and a semiregular variable, pulsating in the first overtone with a period of 142 d. Its bolometric magnitude is Mbol = -4.4 mag. We review what is known about the luminosities of extragalactic symbiotic stars, showing that most, possibly all, contain AGB stars. We suggest that a much larger fraction of Galactic symbiotic stars may contain AGB stars than was previously realized.
KW - Binaries: symbiotic
KW - Galaxies: individual: NGC 6822
KW - Stars: mass-loss
UR - https://www.scopus.com/pages/publications/65349095172
UR - https://www.scopus.com/pages/publications/65349095172#tab=citedBy
U2 - 10.1111/j.1365-2966.2009.14617.x
DO - 10.1111/j.1365-2966.2009.14617.x
M3 - Article
AN - SCOPUS:65349095172
SN - 0035-8711
VL - 395
SP - 1121
EP - 1126
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -