Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Seeing double with K2: Testing re-inflation with two remarkably similar
  planets around red giant branch stars   Despite more than 20 years since the discovery of the first gas giant planet
with an anomalously large radius, the mechanism for planet inflation remains
unknown. Here, we report the discovery of EPIC228754001.01, an inflated gas
giant planet found with the NASA K2 Mission, and a revised mass for another
inflated planet, K2-97b. These planets reside on ~9 day orbits around host
stars which recently evolved into red giants. We constrain the irradiation
history of these planets using models constrained by asteroseismology and
Keck/HIRES spectroscopy and radial velocity measurements. We measure planet
radii of 1.31 +\- 0.11 Rjup and and 1.30 +\- 0.07 Rjup, respectively. These
radii are typical for planets receiving the current irradiation, but not the
former, zero age main sequence irradiation of these planets. This suggests that
the current sizes of these planets are directly correlated to their current
irradiation. Our precise constraints of the masses and radii of the stars and
planets in these systems allow us to constrain the planetary heating efficiency
of both systems as 0.03% +0.03%/-0.02%. These results are consistent with a
planet re-inflation scenario, but suggest the efficiency of planet re-inflation
may be lower than previously theorized. Finally, we discuss the agreement
within 10% of stellar masses and radii, and planet masses, radii, and orbital
periods of both systems and speculate that this may be due to selection bias in
searching for planets around evolved stars.

14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg