J/AJ/150/12 Radial velocity of HD 33643 (Bieryla+, 2015)
KELT-7b: a hot Jupiter transiting a bright V = 8.54 rapidly rotating F-star.
Bieryla A., Collins K., Beatty T.G., Eastman J., Siverd R.J., Pepper J.,
Gaudi B.S., Stassun K.G., Canas C., Latham D.W., Buchhave L.A.,
Sanchis-Ojeda R., Winn J.N., Jensen E.L.N., Kielkopf J.F., McLeod K.K.,
Gregorio J., Colon K.D., Street R., Ross R., Penny M., Mellon S.N.,
Oberst T.E., Fulton B.J., Wang J., Berlind P., Calkins M.L., Esquerdo G.A.,
DePoy D.L., Gould A., Marshall J., Pogge R., Trueblood M., Trueblood P.
<Astron. J., 150, 12 (2015)>
=2015AJ....150...12B 2015AJ....150...12B
ADC_Keywords: Planets ; Stars, double and multiple ; Stars, F-type ;
Radial velocities
Keywords: planetary systems - stars: individual (KELT) -
techniques: photometric - techniques: spectroscopic
Abstract:
We report the discovery of KELT-7b, a transiting hot Jupiter with a
mass of 1.28±0.18MJ, radius of 1.533+0.046-0.047RJ, and an
orbital period of 2.7347749±0.0000039days. The bright host star
(HD33643; KELT-7) is an F-star with V=8.54, Teff=6789+50-49K,
[Fe/H]=0.139+0.075-0.081, and logg=4.149±0.019. It has a mass of
1.535+0.066-0.054M☉, a radius of
1.732+0.043-0.045R☉, and is the fifth most massive, fifth
hottest, and the ninth brightest star known to host a transiting
planet. It is also the brightest star around which Kilodegree
Extremely Little Telescope (KELT) has discovered a transiting planet.
Thus, KELT-7b is an ideal target for detailed characterization given
its relatively low surface gravity, high equilibrium temperature, and
bright host star. The rapid rotation of the star (73±0.5km/s)
results in a Rossiter-McLaughlin effect with an unusually large
amplitude of several hundred m/s. We find that the orbit normal of the
planet is likely to be well-aligned with the stellar spin axis, with a
projected spin-orbit alignment of λ=9.7°±5.2°. This
is currently the second most rapidly rotating star to have a reflex
signal (and thus mass determination) due to a planetary companion
measured.
Description:
The Kilodegree Extremely Little Telescope (KELT) transit survey
(Pepper et al., 2007PASP..119..923P 2007PASP..119..923P) was designed to detect transiting
planets around bright (8<Vmag<10) stars. The KELT-North (KELT-N)
telescope targets this range using a small-aperture (42mm) camera with
a a wide field of view (FOV) of 26°*26°. It observes 13 fields
at declination of 31.7°, roughly equally spaced in right
ascension, in total covering approximately 40% of the Northern sky.
The KELT-N survey has been in operation since 2006 and candidates have
been actively vetted since 2011 April. The KELT-N survey has already
announced four planet discoveries (KELT-1b, Siverd et al. 2012, cat.
J/ApJ/761/123; KELT-2Ab, Beatty et al., 2012ApJ...756L..39B 2012ApJ...756L..39B; KELT-3b,
Pepper et al., 2013ApJ...773...64P 2013ApJ...773...64P; KELT-6b, Collins et al.,
2014AJ....147...39C 2014AJ....147...39C). KELT-7b was discovered and confirmed as a hot
Jupiter transiting the bright V=8.54 star HD33643. KELT-7 is in KELT-N
survey field 04, which is centered on (α=05h:54m:14.71s,
δ=+31d:39m:55.10s; J2000). Field 04 was monitored from
2006 October 26 to 2011 April 1. We obtained follow-up time-series
photometry of KELT-7 between 2012 October and 2014 January.
We used the Tillinghast Reflector Echelle Spectrograph (TRES), on the
1.5m telescope at the Fred Lawrence Whipple Observatory (FLWO) on Mt.
Hopkins, Arizona, to obtain spectra. We obtained a total of 64 TRES
spectra between UT 2012 January 31 and UT 2014 February 21. The
spectra have a resolving power of R=44000. Of the 64 total spectra, 28
were taken on the night of UT 2013 October 19 to measure the
Rossiter-McLaughlin effect (RM; McLaughlin, 1924ApJ....60...22M 1924ApJ....60...22M;
Rossiter, 1924ApJ....60...15R 1924ApJ....60...15R) effect and determine the projected
obliquity of the system.
Objects:
--------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
--------------------------------------------------------------
05 13 10.93 +33 19 05.4 KELT-7 = HD 33643 (P=2.7347749)
--------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 47 64 Radial velocity (RV) observations of KELT-7
--------------------------------------------------------------------------------
See also:
J/AJ/149/149 : Photometry and spectroscopy of HAT-P-54 (Bakos+, 2015)
J/AJ/147/84 : Photometry and spectroscopy of HAT-P-49 (Bieryla+, 2014)
J/ApJ/761/123 : KELT-1 photometry and spectroscopy follow-up (Siverd+, 2012)
J/ApJ/757/18 : RVs for 16 hot Jupiter host stars (Albrecht+, 2012)
J/ApJ/720/1118 : i-band photometry of HAT-P-16 (Buchhave+, 2010)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d BJD Barycentric Julian Date (BJDTDB)
16- 19 I4 m/s RV [-610/265] Relative radial velocity
21- 23 I3 m/s e_RV [48/174] Uncertainty in RV
25- 28 I4 m/s BS [-262/336] Bisector span
30- 32 I3 m/s e_BS [37/209] Uncertainty in BS
34- 41 F8.4 --- Phase [-0.31/275] Phase
43- 47 F5.1 --- S/N [68/298] Signal-to-Noise per resolution element (1)
--------------------------------------------------------------------------------
Note (1): Which takes into account the resolution of the instrument. S/N is
calculated near the peak of the echelle order that includes the MgB lines.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 22-Jul-2015