Two inner dust clumps in PDS 70
Year: 2026
Type: article
Abstract: Context . The wide cavity in the PDS 70 protoplanetary disk harbors two directly imaged confirmed protoplanets. Several studies have proposed the existence of a third inner planet candidate at ~13 au, labeled as PDS 70 d. While its motion is consistent with a Keplerian orbit, its unusually blue spectrum challenges a planetary interpretation. Aims . We investigated the presence and nature of a third inner planet using new SPHERE and GRAVITY observations. Methods . Using the star-hopping strategy, we obtained new coronagraphic SPHERE/IRDIS observations of PDS 70 in dual-polarization imaging mode in the H band, as well as non-coronagraphic observations with SPHERE/IRDIFS covering the YJHK bands. We also searched for a planetary-like signal using GRAVITY+ in astrometric mode with the four-unit-telescope configuration. Results . We consistently detect two inner emission features with SPHERE: one corresponding to the previously proposed planet candidate at ~13 au and another that appears to share the same orbit but leads it by ~120° (clockwise) with a more elongated morphology. Both features exhibit dust-scattered light spectra while displaying different colors, which may indicate differences in dust grain sizes. We show that such a configuration is consistent with co-orbital dust accumulated at the stable Lagrangian regions of a yet undetected planet, distinct from the previously proposed candidate. The analysis of GRAVITY data at the predicted position of this newly proposed planet has resulted in a marginal (3 σ ) detection located between the two clumps along the same orbit ( ρ = 76.2 ± 0.29 mas, and position angle PA = 226.50 ± 0.21°), and consistent with a ~3 M Jup planet. This planet-like signal aligns with a narrow shadow detected in the outer disk with SPHERE. Additionally, with SPHERE we detect polarized emission very close to the star, which likely arise from the inner disk, with an inclination of 50° and a PA of ~135°. The fact that the two dust clumps appear embedded within this polarized emission motivates an inner disk-related alternative scenario. Conclusions . We conclude that the emission from the previously reported third planet candidate could arise either from a dust clump trailing a yet undetected planet along the same orbit, or from a rotating substructure within the inner disk. Additional observations are required to further test these two proposed scenarios. In particular, confirming the new GRAVITY planet-like signal would support the use of co-orbital substructures as indirect tracers of embedded planets.
Source: Astronomy and Astrophysics
Institutions: Centro de Astrobiología, Centre National de la Recherche Scientifique, University of Liège, Université Paris Cité, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, Astrophysique, Instrumentation et Modélisation, KU Leuven, Max Planck Institute for Astronomy, European Southern Observatory, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, European Southern Observatory, CY Cergy Paris Université, Herzberg Institute of Astrophysics, University of Victoria, University of Florida, Pontificia Universidad Católica de Chile, University of Geneva, Indiana University, Queen Mary University of London, University of Cambridge, University of Arizona
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Awards: G1175115578, G121809054, G1401168639, G1594096898, G1855990336, G210041235, G2262748287, G2309174360, G2350454921, G2575235166, G2601397997, G2660406951, G279363373, G300979063, European Project on Mendelian Forms of Parkinson’s Disease, G34346518, G3480869486, G3518538256, G3681454997, G3690828678, G3909124325, G4008337681, G4042783231, G425668148, G430777504, G4442677895, G4484233699, G4526231891, G464105488, G5080475149, G5195188938, G5421974903, G5721199125, G5731992407, G6394348679, G6874468849, G7084143925, G745419941, G7516519635, G8308124115, G8575141037, G8684520763, G8920660035, G897484643, G99296377
OpenAlex ID: W7202125625