2018A&A...615L..14M

Context. VLA 1623-2417 is a triple protostellar system deeply embedded in Ophiuchus A. Sources A and B have a separation of 1.1'', making their study difficult beyond the submillimeter regime. Lack of circumstellar gas emission suggested that VLA 1623-2417 B has a very cold envelope and is much younger than source A, which is generally considered the prototypical Class 0 source.
Aims. We explore the consequences of new ALMA Band 9 data on the spectral energy distribution (SED) of VLA 1623-2417 and their inferred nature.
Methods. We constructed and analyzed the SED of each component in VLA 1623-2417 using dust continuum observations spanning from centimeter to near-infrared wavelengths.
Results. The ALMA Band 9 data presented in this work show that the SED of VLA 1623-2417 B does not peak at 850um as previously expected, but instead presents the same shape as VLA 1623-2417 A at wavelengths shorter than 450um.
Conclusions. The results presented in this work indicate that the previous assumption that the flux in Herschel and Spitzer observations is solely dominated by VLA 1623-2417 A is not valid, and instead, VLA 1623-2417 B most likely contributes a significant portion of the flux at λ<450um. These results, however, do not explain the lack of circumstellar gas emission and puzzling nature of VLA 1623-2417 B.