Multiwavelength detection of an ongoing FUOr-type outburst on a low-mass YSO

Zhen Guo, P. W. Lucas, R. G. Kurtev, J. Borissova, V. Elbakyan, C. Morris, A. Bayo, L. Smith, A. Caratti o Garatti, C. Contreras Peña, D. Minniti, J. Jose, M. Ashraf, J Alonso-García, N. Miller, H. D. S. Muthu

Research output: Contribution to journalArticlepeer-review

15 Downloads (Pure)


During the pre-main-sequence evolution, Young Stellar Objects (YSOs) assemble most of their mass during the episodic accretion process. The rarely seen FUOr-type events are valuable laboratories to investigate the outbursting nature of YSOs. Here, we present multiwavelength detection of a high-amplitude eruptive source in the young open cluster VdBH 221 with an ongoing outburst, including optical to mid-infrared time series and near-infrared spectra. The initial outburst has an exceptional amplitude of >6.3 mag in Gaia and 4.6 mag in Ks, with a peak luminosity up to 16 L⊙ and a peak mass accretion rate of 1.4 × 10-5 M⊙ yr-1. The optical to infrared spectral energy distribution of this object is consistent with a low-mass star (0.2 M⊙) with a modest extinction (AV < 2 mag). A 100-d delay between optical and infrared rising stages is detected, suggesting an outside-in origin of the instability. The spectroscopic features of this object reveal a self-luminous accretion disc, very similar to FU Orionis, with a low line-of-sight extinction. Most recently, there has been a gradual increase in brightness throughout the wavelength range, possibly suggesting an enhancement of the mass accretion rate.

Original languageEnglish
Article numberslad201
Pages (from-to)L115-L122
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
Early online date26 Jan 2024
Publication statusPublished - 1 Mar 2024


  • astro-ph.SR
  • astro-ph.GA
  • stars: pre-main sequence
  • infrared: stars
  • stars: variables: T Tauri, Herbig Ae/Be
  • stars: protostar
  • accretion, accretion discs


Dive into the research topics of 'Multiwavelength detection of an ongoing FUOr-type outburst on a low-mass YSO'. Together they form a unique fingerprint.

Cite this