J/A+A/551/A11 Light curves of HAT-P-8 (Mancini+, 2013)
A lower radius and mass for the transiting extrasolar planet HAT-P-8b.
Mancini L., Southworth J., Ciceri S., Fortney J.J., Morley C.V.,
Dittmann J.A., Tregloan-Reed J., Bruni I., Barbieri M., Evans D.F.,
D'Ago G., Nikolov N., Henning T.
<Astron. Astrophys. 551, A11 (2013)>
=2013A&A...551A..11M 2013A&A...551A..11M
ADC_Keywords: Stars, double and multiple ; Planets ; Photometry
Keywords: planets and satellites: fundamental parameters -
stars: fundamental parameters - stars: individual: HAT-P-8
Abstract:
The extrasolar planet HAT-P-8 b was thought to be one of the more
inflated transiting hot Jupiters. Aims. By using new and existing
photometric data, we computed precise estimates of the physical
properties of the system. Methods. We present photometric observations
comprising eleven light curves covering six transit events, obtained
using five medium-class telescopes and telescope-defocussing
technique. One transit was simultaneously obtained through four
optical filters, and two transits were followed contemporaneously from
two observatories. We modelled these and seven published datasets
using the jktebop code. The physical parameters of the system were
obtained from these results and from published spectroscopic
measurements. In addition, we investigated the theoretically-predicted
variation of the apparent planetary radius as a function of
wavelength, covering the range 330-960nm. Results. We find that
HAT-P-8 b has a significantly lower radius (1.321RJup) and mass
(1.275MJup) compared to previous estimates (1.50RJup and
1.52MJup respectively). We also detect a radius variation in the
optical bands that, when compared with synthetic spectra of the
planet, may indicate the presence of a strong optical absorber,
perhaps TiO and VO gases, near the terminator of HAT-P-8 b.
Conclusions. These new results imply that HAT-P-8 b is not
significantly inflated, and that its position in the planetary
mass-radius diagram is congruent with those of many other transiting
extrasolar planets.
Description:
Light curves of four transits of the extrasolar planetary system
HAT-P-8 are presented, obtained with substantial telescope defocussing
in order to improve the photometric precision of the observations.
Four of the datasets were obtained using the CA 2.2m telescope, BUSCA
camera and sdss-u, Gunn-g, Gunn-r, Gunn-z filters at CAHA (Spain) in
2012. Three of the datasets were obtained using the Cassini 1.5m
telescope, BFOSC camera and Gunn-r, Gunn-i and Johnson-I filters at
INAF/OAB (Loiano, Italy) in 2009, 2011 and 2012.Two of the datasets
were obtained using the CA 1.23m telescope, CCD camera and Johnson-r
and I filters at CAHA (Spain) in 2011 and 2012. One of the datasets
was obtained using the 2.5m NTT, WFC and Stromgren-y filter at La
Palma (Spain) in 2010. One of the datasets was obtained using the
Kuiper 1.55m telescope, CCD camera and Arizona-y filter at Mt. Bigelow
(Arizona, USA) in 2009.
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
22 52 09.86 +35 26 49.6 HAT-P-8 = TYC 2757-1152-1
----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
ca123cm1.dat 37 166 Photometry of HAT-P-8 on 2011-10-05 (R CA 1.23m)
ca123cm2.dat 37 373 Photometry of HAT-P-8 on 2012-10-02 (I CA 1.23m)
ca220cmg.dat 37 157 Photometry of HAT-P-8 on 2012-08-26 (g CA 2.3m)
ca220cmr.dat 37 159 Photometry of HAT-P-8 on 2012-08-26 (r CA 2.3m)
ca220cmu.dat 37 160 Photometry of HAT-P-8 on 2012-08-26 (u CA 2.3m)
ca220cmz.dat 37 162 Photometry of HAT-P-8 on 2012-08-26 (z CA 2.3m)
cassini1.dat 37 103 Photometry of HAT-P-8 on 2009-11-12 (r Cassini)
cassini2.dat 37 469 Photometry of HAT-P-8 on 2011-10-05 (i Cassini)
cassini3.dat 37 245 Photometry of HAT-P-8 on 2012-10-02 (I Cassini)
int.dat 37 138 Photometry of HAT-P-8 on 2010-08-28 (y INT)
kuiper.dat 37 1083 Photometry of HAT-P-8 on 2009-10-22 (I Kuiper)
--------------------------------------------------------------------------------
See also:
J/MNRAS/408/1680 : Transiting planetary system WASP-2 (Southworth+, 2010)
J/MNRAS/396/1023 : Transiting planetary system WASP-5 (Southworth+, 2009)
J/MNRAS/399/287 : Transiting planetary system WASP-4 (Southworth+, 2009)
J/A+A/527/A8 : Transiting planetary system WASP-7 (Southworth+, 2011)
J/ApJ/707/167 : Transiting planetary system WASP-18 (Southworth+, 2009)
J/MNRAS/426/1338 : Transiting planetary system WASP-17 (Southworth+, 2012)
J/MNRAS/422/3099 : Transiting planetary system HAT-P-5 (Southworth+, 2012)
J/MNRAS/420/2580 : Transiting planetary system HAT-P-13 (Southworth+, 2012)
J/A+A/549/A10 : Transiting planetary system GJ1214 (Harpsoe+, 2013)
Byte-by-byte Description of file: *.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.7 d BJD Barycentric JD for the midpoint of observation
(TDB, BJD-2400000)
16- 26 F11.8 mag mag Differential magnitude of WASP-2
29- 37 F9.7 mag e_mag Measurement error of magnitude
--------------------------------------------------------------------------------
Acknowledgements:
Luigi Mancini, Max Planck Institute for Astronomy, Germany,
mancini(at)mpia.de
(End) Luigi Mancini [Max Planck Inst.], Patricia Vannier [CDS] 29-Jan-2013