Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: K2 spots rotation in the helium star HD144941   HD144941 is an evolved early-type metal-poor low-mass star with a
hydrogen-poor surface. It is frequently associated with other intermediate
helium-rich subdwarfs and extreme helium stars. Previous photometric studies
have failed to detect any variability. New observations with the K2 mission
show complex but periodic variations with a full amplitude of 4 parts per
thousand. It is proposed that these are due to an inhomogeneous surface
brightness distribution (spots) superimposed on a rotation period of 13.9+/-0.2
d. The cause of the surface inhomogeneity is not identified, although an
oblique dipolar magnetic field origin is plausible.

27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
19
The categories of this paper are: eess