Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic field, differential rotation and activity of the hot-Jupiter
  hosting star HD 179949   HD 179949 is an F8V star, orbited by a giant planet at ~8 R* every 3.092514
days. The system was reported to undergo episodes of stellar activity
enhancement modulated by the orbital period, interpreted as caused by
Star-Planet Interactions (SPIs). One possible cause of SPIs is the large-scale
magnetic field of the host star in which the close-in giant planet orbits.
  In this paper we present spectropolarimetric observations of HD 179949 during
two observing campaigns (2009 September and 2007 June). We detect a weak
large-scale magnetic field of a few Gauss at the surface of the star. The field
configuration is mainly poloidal at both observing epochs. The star is found to
rotate differentially, with a surface rotation shear of dOmega=0.216\pm0.061
rad/d, corresponding to equatorial and polar rotation periods of 7.62\pm0.07
and 10.3\pm0.8 d respectively. The coronal field estimated by extrapolating the
surface maps resembles a dipole tilted at ~70 degrees. We also find that the
chromospheric activity of HD 179949 is mainly modulated by the rotation of the
star, with two clear maxima per rotation period as expected from a highly
tilted magnetosphere. In September 2009, we find that the activity of HD 179949
shows hints of low amplitude fluctuations with a period close to the beat
period of the system.

33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga