Differentiating formation models with new dynamical masses for the PDS 70 protoplanets
Hot- and cold-start planet formation models predict differing luminosities for the young, bright planets that direct-imaging surveys are most sensitive to. However, precise mass estimates are required to distinguish between these models observationally. The presence of two directly imaged planets, PDS 70 b and c, in the PDS 70 protoplanetary disk provides us a unique opportunity for dynamical mass measurements since the masses of these planets are currently poorly constrained. Fitting orbital parameters to new astrometry of these planets, taken with VLTI/GRAVITY in the K band, we find 2 σ dynamical upper mass limits of 4.9 M Jup for b and 13.6 M Jup for c. Adding astrometry from the newly proposed planet candidate PDS 70 d into our model, we determine 2 σ dynamical upper mass limits of 5.3 M Jup , 7.5 M Jup , and 2.2 M Jup for b, c, and the candidate d, respectively. However, N -body analysis of the orbits’ fit in this case suggests that the inclusion of d makes the system unstable. Using the upper mass limits for b and c, we rule out the coldest-start formation models for both planets, calculating minimum post-formation entropies ( S i ) of 9.5 k B / baryon and 8.4 k B / baryon, respectively. This places PDS 70 b and c on the growing list of directly imaged planets inconsistent with cold-start formation.
Authors
- Jens Kammerer (ORCID: https://orcid.org/0000-0003-2769-0438)
- Gabriel-Dominique Marleau (ORCID: https://orcid.org/0000-0002-2919-7500)
- Jonas Sauter
- S. Lacour (ORCID: https://orcid.org/0000-0002-6948-0263)
- Sasha Hinkley (ORCID: https://orcid.org/0000-0001-8074-2562)
- M. Houllé (ORCID: https://orcid.org/0000-0001-5633-2010)
- D. Mesa (ORCID: https://orcid.org/0000-0001-8467-1933)
- Emily Rickman (ORCID: https://orcid.org/0000-0003-4203-9715)
- Laura Kreidberg (ORCID: https://orcid.org/0000-0003-0514-1147)
- Sarah Blunt (ORCID: https://orcid.org/0000-0002-3199-2888)
- G. P. P. L. Otten (ORCID: https://orcid.org/0000-0002-6717-1977)
- Remo Burn (ORCID: https://orcid.org/0000-0002-9020-7309)
- Valentin Christiaens (ORCID: https://orcid.org/0000-0002-0101-8814)
- David Trevascus (ORCID: https://orcid.org/0000-0003-4497-6622)
- Iain Hammond (ORCID: https://orcid.org/0000-0003-1502-4315)
- R. Gratton (ORCID: https://orcid.org/0000-0003-2195-6805)
- Elisabeth C. Matthews (ORCID: https://orcid.org/0000-0003-0593-1560)
- A. Vigan (ORCID: https://orcid.org/0000-0002-5902-7828)
- G. Chauvin
- Jason Wang (ORCID: https://orcid.org/0000-0003-0774-6502)
- Mickael Bonnefoy
- J. Sánchez-Bermúdez (ORCID: https://orcid.org/0000-0002-9723-0421)
- Wolfgang Brandner (ORCID: https://orcid.org/0000-0003-1939-6351)
- Mathias Nowak
- William O. Balmer (ORCID: https://orcid.org/0000-0001-6396-8439)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-04-23
- DOI
- https://doi.org/10.1051/0004-6361/202553936
- Citations
- 5
- Primary Topic
- Astro and Planetary Science
- Type
- article
- Field-Weighted Citation Impact
- 5.77