Year: 2026
Type: preprint
Abstract: Unstable mass accretion in young stellar objects (YSOs) often leads to observable outbursts, which play a key role in stellar mass assembly during pre-main-sequence evolution. The highest-amplitude, longest-duration events are classified as FUors. Until recently, only 50 FUor events had been confirmed. Many occur in embedded protostars, which are difficult to monitor in optical surveys. We present photometric and spectroscopic observations of SPICY 30021, an eruptive young star discovered in the mid-infrared (MIR) NEOWISE time series. We aim to construct its spectral energy distribution and characterise its eruptive nature. We compiled multi-wavelength photometric time series from NEOWISE, VVV and VVV-RENEW, and obtained photometric and spectroscopic observations during the outburst with SOAR, Magellan and VLT, including data from the ESO public survey VVVX-GalCen. We identified the outbursting source, separated it from nearby companions, and estimated the line-of-sight extinction from spectroscopic features. Stellar parameters were constrained using radial velocity, proper motions and stellar evolution models. SPICY 30021 is an optically obscured FUor with a total interstellar and circumstellar extinction of Av = 12.5 mag. Its spectrum closely resembles those of classical FUors. Multiple methods yield a distance of 1.7+_0.4 kpc. Its accretion luminosity is Lacc = 32 L_sol, moderate among FUors. Quiescent near-infrared photometry is consistent with a young 0.9 M_sol progenitor, although the mass depends on the adopted model and distance. We confirm SPICY 30021 as a bona fide FUor event. Its MIR precursor suggests an outside-in triggering mechanism.
Source: arXiv (Cornell University)
Authors: Guo, Zhen, Morris, Calum, Fermiano, Vitor, Lizana-Vidal, Carolina, Aliaga, Aldo, Osses, Javier, Navarete, Felipe, Lucas, Philip, Saito, Roberto K., Carvalho, Adolfo, Elbakyan, Vardan, Peña, Carlos Contreras, Singh, Koshvendra, Fang, Min, Weber, Philipp, Zhao, He, Magakian, Tigran Yu., Movsessian, Tigran A., Gomez, Matias, Minniti, Dante, Ivanov, Valentin, Navarro, Maria Gabriela, Federle, Sara, Petralia, Ilaria, Luna, Alonso, Corral-Santana, Jesus, Garro, Elisa R., Points, Sean D., Briceño, Cesar, Zhang, Zenghua, Kurtev, Radostin, Borissova, Jura, Fernández-Trincado, Jose G., Alonso-García, Javier, Cáceres, Claudio, Obasi, Casmir O., Galdeano, Daniela, Baravalle, Laura, Giannini, Teresa, Zhu, Zhikai
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, Michigan State University, Chinese Academy of Sciences South America Center for Astronomy, European Commission, Ministério da Ciência, Tecnologia e Inovação, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Ministry of Science and Higher Education of the Russian Federation, Universidad Andrés Bello, Agencia Nacional de Investigación y Desarrollo, Jet Propulsion Laboratory, College of Engineering, Michigan State University, University of North Carolina at Chapel Hill, Agencia Estatal de Investigación, NextGenerationEU
Awards: CONSTRAINING THE ORIGIN OF O-TYPE STARS THROUGH THEIR PROGENITOR IDENTIFICATION., G166539506, G1757217292, G1799927510, MILLENNIUM NUCLEUS ON YOUNG EXOPLANETS AND THEIR MOONS, G2945112853, G318412399, INVESTIGATE THE EPISODIC ACCRETION BEHAVIOUR ON YOUNG STELLAR OBJECTS: A NEW POSTDOCTORAL POSITION AT THE UNIVERSIDAD DE VALPARAISO_X000D_, RAPID: Fast Mobility Particle Size Measurements during the 4th Fire Lab at Missoula Experiment (FLAME IV) Study, G4008337681, G4728539003, G4993905653, G5195188938, G5461701949, G5779771523, G5794854969, G6520718613, TRACKING DOWN THE ROOTS OF THE GLOBULAR CLUSTER - BLACK HOLE RELATION, G7610025757, UNVEILING THE HIDDEN GALACTIC PLANE A NEAR-INFRARED VIEW OF THE STELLAR POPULATIONS AND THE STAR CLUSTERS AT LOW-GALACTIC LATITUDES, G863151887, CENTRO DE ASTROFISICA Y TECNOLOGIAS AFINES (CATA), G8890173333, G9000173888
OpenAlex ID: W7222349483