Astronomers Have Detected a Galaxy Millions of Years Older Than Any Previously Observed

Researchers estimate that MoM z14 was created 280 million years after the Big Bang, 10 million years earlier than the previous most primitive galaxy recorded.

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 2σ dynamical upper mass limits of 4.9 M<SUB>Jup</SUB> for b and 13.6 M<SUB>Jup</SUB> for c. Adding astrometry from the newly proposed planet candidate PDS 70 d into our model, we determine 2σ dynamical upper mass limits of 5.3 M<SUB>Jup</SUB>, 7.5 M<SUB>Jup</SUB>, and 2.2 M<SUB>Jup</SUB> 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 <SUB>i</SUB>) of 9.5 k<SUB>B</SUB>/baryon and 8.4 k<SUB>B</SUB>/baryon, respectively. This places PDS 70 b and c on the growing list of directly imaged planets inconsistent with cold-start formation.

LSST Solar System Predictions

5 scientists on finding meaning in our Universe's 13.8-billion-year story

“We are an embodiment of the history of the Universe, literally history embodied in an incredibly emergent phenomenon here.”