Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An upper boundary in the mass-metallicity plane of exo-Neptunes   With the progress of detection techniques, the number of low-mass and
small-size exoplanets is increasing rapidly. However their characteristics and
formation mechanisms are not yet fully understood. The metallicity of the host
star is a critical parameter in such processes and can impact the occurence
rate or physical properties of these planets. While a frequency-metallicity
correlation has been found for giant planets, this is still an ongoing debate
for their smaller counterparts. Using the published parameters of a sample of
157 exoplanets lighter than 40 Mearth, we explore the mass-metallicity space of
Neptunes and Super-Earths. We show the existence of a maximal mass that
increases with metallicity, that also depends on the period of these planets.
This seems to favor in situ formation or alternatively a metallicity-driven
migration mechanism. It also suggests that the frequency of Neptunes (between
10 and 40 Mearth) is, like giant planets, correlated with the host star
metallicity, whereas no correlation is found for Super-Earths (<10 Mearth).

31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an