J/A+A/627/A28 beta Pic BRITE, bRing, SMEI light curves (Zwintz+, 2019)
Revisiting the pulsational characteristics of the exoplanet host star
β Pictoris.
Zwintz K., Reese D.R., Neiner C., Pigulski A., Kuschnig R., Muellner M.,
Zieba S., Abe L., Guillot T., Handler G., Kenworthy M., Stuik R.,
Moffat A.F.J., Popowicz A., Rucinski S.M., Wade G.A., Weiss W.W.,
Bailey J.I. III, Crawford S., Ireland M., Lomberg B., Mamajek E.E.,
Mellon S.N., Talens G.J.
<Astron. Astrophys. 627, A28 (2019)>
=2019A&A...627A..28Z 2019A&A...627A..28Z (SIMBAD/NED BibCode)
ADC_Keywords: Combined data; Magnetic fields; Models; Photometry, CCD;
Space observations; Stars, A-type; Stars, variable
Keywords: asteroseismology - stars: individual: beta Pictoris -
stars: interiors - stars: variables: delta Scuti -
stars: magnetic field
Abstract:
Exoplanet properties crucially depend on the parameters of their host
stars: more accurate stellar parameters yield more accurate exoplanet
characteristics. When the exoplanet host star shows pulsations,
asteroseismology can be used for an improved description of the
stellar parameters.
We aim to revisit the pulsational properties of β Pic and
identify its pulsation modes from normalized amplitudes in five
different passbands. We also investigate the potential presence of a
magnetic field.
We conducted a frequency analysis using three seasons of
BRITE-Constellation observations in the two BRITE filters, the about
620-day-long bRing light curve, and the nearly 8-year-long SMEI
photometric time series. We calculated normalized amplitudes using all
passbands and including previously published values obtained from
ASTEP observations. We investigated the magnetic properties of β
Pic using spectropolarimetric observations conducted with the HARPSpol
instrument. Using 2D rotating models, we fit the normalized amplitudes
and frequencies through Monte Carlo Markov chains.
We identify 15 pulsation frequencies in the range from 34 to 55d-1,
where two, F13 at 53.6917d-1 and F11 at 50.4921d-1, display clear
amplitude variability. We use the normalized amplitudes in up to five
passbands to identify the modes as three l=1, six l=2, and six l=3
modes. β Pic is shown to be non-magnetic with an upper limit of
the possible undetected dipolar field of 300 Gauss.
Multiple fits to the frequencies and normalized amplitudes are
obtained, including one with a near equator-on inclination for β
Pic, which corresponds to our expectations based on the orbital
inclination of β Pic b and the orientation of the circumstellar
disk. This solution leads to a rotation rate of 27% of the Keplerian
breakup velocity, a radius of 1.497±0.025R☉, and a mass of
1.797±0.035M☉. The ∼2% errors in radius and mass do not
account for uncertainties in the models and a potentially erroneous
mode-identification.
Description:
Reduced light curves for beta Pictoris obtained with the
BRITE-Constellation satellites from 16 March 2015 to 2 June 2015 with
BHr (brite1.dat), from 15 December 2016 to 21 June 2017 with BLb
(brite2.dat), from 4 November 2016 to 17 June 2017 with BHr and BTr
(combined; brite3.dat) and from 9 November 2017 to 25 April 2018 with
BHr (brite4.dat).
The first column lists heliocentric Julian Date for
mid-exposure-2456000.0, the second column is reduced and decorrelated
instrumental BRITE magnitude.
Reduced light curve for beta Pictoris obtained with SMEI from 6
February 2003 to 30 December 2010 (smei.dat) where the first column
lists heliocentric Julian Date-2450000.0, the second column is the
corrected SMEI magnitude and the third column provides the uncertainty
of column 2.
Reduced light curve for beta Pictoris obtained with bRing from 2
February 2017 to 16 October 2018. The first column lists the time in
Julian Date (JD) and the second column is the reduced flux in
instrumental magnitudes.
Objects:
----------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------
05 47 17.09 -51 03 59.4 beta Pic = HR 2020
----------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
brite1.dat 21 44236 BRITE time, magnitudes
brite2.dat 21 74306 BRITE time, magnitudes
brite3.dat 21 67578 BRITE time, magnitudes
brite4.dat 21 53262 BRITE time, magnitudes
bring.dat 35 67121 BRING time, magnitudes
smei.dat 29 28623 SMEI time, magnitudes and uncertainties
--------------------------------------------------------------------------------
See also:
J/A+A/299/557 : Light variations on Beta Pic (Lecavelier des Etangs+, 1995)
J/A+A/542/A18 : βPic Harps radial velocity data (Lagrange+, 2012)
J/ApJ/823/108 : A dust model for bet Pic from 0.58 to 870um (Ballering+, 2016)
J/A+A/607/A25 : beta Pic HARPS spectrum (Vidal-Madjar+, 2017)
Byte-by-byte Description of file: brite1.dat brite2.dat brite3.dat brite4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.9 d Time HJD-2456000.0
15- 21 F7.3 mmag Flux Reduced instrumental magnitudes
--------------------------------------------------------------------------------
Byte-by-byte Description of file: bring.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 21 F21.12 d Time Julian Date
22- 35 F14.7 mmag Flux Reduced instrumental magnitudes
--------------------------------------------------------------------------------
Byte-by-byte Description of file: smei.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.8 d Time HJD-2450000.0
14- 21 F8.5 mag Flux Reduced instrumental magnitudes
22- 29 F8.5 mag e_Flux Error of reduced instrumental magnitudes
--------------------------------------------------------------------------------
Acknowledgements:
Konstanze Zwintz, konstanze.zwintz(at)uibk.ac.at
(End) Konstanze Zwintz [Univ. Innsbruck], Patricia Vannier [CDS] 03-Jun-2019