TY - JOUR
T1 - The enigma of Gaia18cjb
T2 - A possible rare hybrid of FUor and EXor properties
AU - Fiorellino, Eleonora
AU - Ábrahám, Péter
AU - Kóspál, Ágnes
AU - Kun, Mária
AU - Alcalá, Juan M.
AU - Caratti O Garatti, Alessio
AU - Cruz-Sáenz De Miera, Fernando
AU - García-Álvarez, David
AU - Giannini, Teresa
AU - Park, Sunkyung
AU - Siwak, Michal
AU - Szilágyi, Máté
AU - Covino, Elvira
AU - Marton, Gabor
AU - Nagy, Zsófia
AU - Nisini, Brunella
AU - Marianna Szabó, Zsófia
AU - Bora, Zsófia
AU - Cseh, Borbála
AU - Kalup, Csilla
AU - Krezinger, Máte
AU - Kriskovics, Levente
AU - Ogloza, Waldemar
AU - Pál, András
AU - Sódor, Ádám
AU - Sonbas, Eda
AU - Szakáts, Róbert
AU - Vida, Krisztián
AU - Vinkó, József
AU - Wyrzykowski, Lukasz
AU - Zielinski, Pawel
N1 - Publisher Copyright:
© The Authors 2024.
PY - 2024/6/1
Y1 - 2024/6/1
N2 - Context. Gaia18cjb is one of the Gaia-alerted eruptive young star candidates that has been experiencing a slow and strong brightening during the last 13 years, similarly to some FU Orionis-type objects. Aims. The aim of this work is to derive the young stellar nature of Gaia18cjb and determine its physical and accretion properties to classify its variability. Methods. We conducted monitoring observations using multi-filter optical and near-infrared (NIR) photometry, as well as NIR spectroscopy. We present an analysis of pre-outburst and outburst optical and IR light curves, color-magnitude diagrams in different bands, the detection of NIR spectral lines, and estimates of both stellar and accretion parameters during the burst. Results. The optical light curve shows an unusually long (over 8 years) brightening event of 5 mag in the last 13 years, before reaching a plateau indicating that the burst is still ongoing, suggesting a FU Orionis-like (FUor-like) nature. The same outburst is less strong in the IR light curves. The NIR spectra, obtained during the outburst, exhibit emission lines typical of highly accreting low-intermediate mass young stars with typical EX Lupi-type (EXor) features. The spectral index of Gaia18cjb SED classifies it as a Class I in the pre-burst stage and a flat-spectrum young stellar object (YSO) during the burst. Conclusions. Gaia18cjb is an eruptive YSO that exhibits FUor-like photometric features (in terms of brightening amplitude and length of the burst) as well as EXor-like spectroscopic features and accretion rate. Its nature appears similar to that of V350 Cep and V1647 Ori, which have been classified as objects in between FUors and EXors.
AB - Context. Gaia18cjb is one of the Gaia-alerted eruptive young star candidates that has been experiencing a slow and strong brightening during the last 13 years, similarly to some FU Orionis-type objects. Aims. The aim of this work is to derive the young stellar nature of Gaia18cjb and determine its physical and accretion properties to classify its variability. Methods. We conducted monitoring observations using multi-filter optical and near-infrared (NIR) photometry, as well as NIR spectroscopy. We present an analysis of pre-outburst and outburst optical and IR light curves, color-magnitude diagrams in different bands, the detection of NIR spectral lines, and estimates of both stellar and accretion parameters during the burst. Results. The optical light curve shows an unusually long (over 8 years) brightening event of 5 mag in the last 13 years, before reaching a plateau indicating that the burst is still ongoing, suggesting a FU Orionis-like (FUor-like) nature. The same outburst is less strong in the IR light curves. The NIR spectra, obtained during the outburst, exhibit emission lines typical of highly accreting low-intermediate mass young stars with typical EX Lupi-type (EXor) features. The spectral index of Gaia18cjb SED classifies it as a Class I in the pre-burst stage and a flat-spectrum young stellar object (YSO) during the burst. Conclusions. Gaia18cjb is an eruptive YSO that exhibits FUor-like photometric features (in terms of brightening amplitude and length of the burst) as well as EXor-like spectroscopic features and accretion rate. Its nature appears similar to that of V350 Cep and V1647 Ori, which have been classified as objects in between FUors and EXors.
KW - Accretion
KW - Accretion disks
KW - Stars: formation
KW - Stars: low-mass
KW - Stars: pre-main sequence
KW - Stars: protostars
KW - Techniques: imaging spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85195802409&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/202347777
DO - 10.1051/0004-6361/202347777
M3 - Article
AN - SCOPUS:85195802409
SN - 0004-6361
VL - 686
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A160
ER -