Observation of an Accreting Planetary-Mass Companion with Signs of Disk-Disk Interaction in Orion

TL;DR

The paper reports the discovery of a planetary-mass companion, V2376 Ori b, at a projected separation of about 71 au from V2376 Ori in the Orion D association, identified in JWST NIRCam imaging and confirmed spectroscopically with VLT/MUSE. SED fitting yields an effective temperature around 2100 K and a luminosity of roughly 0.004 L_sun, implying a mass near 10–30 M_Jup for an age of about 7 ± 3 Myr. MUSE spectroscopy reveals multiple accretion tracers and yields an accretion luminosity of about 10^-3.6 L_sun and a mass accretion rate near 10^-6.5 M_Jup/yr, with additional detections of [O II] and [CI] lines. Extended [O II] emission suggests a tidal interaction or mass transfer between circumstellar/circumplanetary disks, evidenced by a bridge and arc-like structure; these observations demonstrate JWST’s power to uncover young PMCs and motivate further high-resolution follow-up to study disk–disk interactions in forming planetary systems.

Abstract

Young ($\lesssim 10$ Myr) planetary-mass companions (PMCs) provide valuable insights into the formation and early evolution of planetary systems. To date, only a dozen such objects have been identified through direct imaging. Using JWST/NIRCam observations towards the Orion Nebula, obtained as part of the \textit{PDRs4All} Early Release Science program, we have identified a faint point source near the M-type star V2376 Ori. Follow-up spectroscopic observations with the MUSE instrument on the VLT confirm that the source, V2376 Ori b, is indeed a young planetary-mass companion. It is a member of Orion D, around 80\,pc in the foreground of the Trapezium cluster of Orion and with an age of approximately $7 \pm 3$ Myr. We fit the SED of V2376 Ori b to infer a mass of $ \sim 20~M_{\rm Jup}$. The MUSE spectrum reveals several accretion tracers. Based on the H$α$ line intensity, we estimate an accretion rate of $\sim$10$^{-6.5 \pm 0.7}~\rm M_{Jup}\,yr^{-1}$, which is comparable to that of young PMCs such as PDS~70b. In addition, the MUSE data cube reveals extended emission in the [O\,\textsc{ii}] doublet at 7320 and 7330~Å, which is interpreted as evidence of a dynamical interaction between the two sources that, potentially, involves mass transfer between their individual accretion disks. These results demonstrate that JWST/NIRCam imaging surveys of young stellar associations can uncover new PMCs, which can then be confirmed and characterized through ground-based spectroscopic follow-up.

Figures (10)

• Figure 1: V2376 Ori observations. (A to E) HST ACS/WFC optical image ricci_hubble_2008. (F to L) JWST near-infrared images habart_pdrs4all_2024. The red dashed circle (pointed by the red arrow) in panel (G) indicates the aperture shape used to extract the V2376 Ori b fluxes. The wavelength and physical assignment of each image are labeled above each panel for the narrowband filters. Black pixels are saturated.
• Figure 2: (A to C) Continuum-subtracted maps. (A) Integrated cube (6908-9158 Å). (B) [Ci] $\lambda$8272 integrated map. (C) Sum of the integrated maps of the [Oii] doublet at 7320 and 7330 Å. White dashed contours indicate intensity levels. Their spacing are indicated with the whites lines on the colorbars. (D) MUSE spectrum (blue) and HST photometry (orange dots) of V2376 Ori b. HST filter widths are indicated by orange bars. Green lines mark recombination features, other lines are labeled in black.
• Figure 3: Spectral energy distribution (SED) of V2376 Ori b from HST (triangles) and JWST (dots) photometry, shown as black markers with error bars (invisible when smaller than markers). The green dashed line is the best-fit blackbody ($T = 2100$ K), with red and blue dotted lines showing the $T = 1800$ K and 2300 K limits. The orange line shows the best-fit BT-Cond model ($T = 2400$ K, $\log g = 4$).
• Figure 4: Contours of the HST F435W image (continuous blue lines) and JWST F187N image (red dashed lines). Both images are north-aligned, centered on V2376 Ori and oversampled on a grid with pixel sizes of 0.003". The full width half maxima of the point spread functions are shown with circles in the bottom-left corner, for each instrument.
• Figure 5: Evolutionary tracks from the model of baraffe_evolutionary_2003 showing the temporal evolution of (top) the luminosity and (bottom) the effective temperature ($T_{\rm eff}$) for cool brown dwarfs and giant exoplanets. Each curve corresponds to a specific mass (in $\rm M_\odot$), as labeled at the end of the tracks. The red data point represents the companion V2376 Ori b, plotted with its age and luminosity (top panel), and its effective temperature (bottom panel), with associated uncertainties, using the black body model fitted to the SED.