J/ApJ/761/123 KELT-1 photometry and spectroscopy follow-up (Siverd+, 2012)
KELT-1b: a strongly irradiated, highly inflated, short period,
27 jupiter-mass companion transiting a mid-F star.
Siverd R.J., Beatty T.G., Pepper J., Eastman J.D., Collins K., Bieryla A.,
Latham D.W., Buchhave L.A., Jensen E.L.N., Crepp J.R., Street R.,
Stassun K.G., Gaudi B.S., Berlind P., Calkins M.L., Depoy D.L.,
Esquerdo G.A., Fulton B.J., Furesz G., Geary J.C., Gould A., Hebb L.,
Kielkopf J.F., Marshall J.L., Pogge R., Stanek K.Z., Stefanik R.P.,
Szentgyorgyi A.H., Trueblood M., Trueblood P., Stutz A.M., van Saders J.L.
<Astrophys. J., 761, 123 (2012)>
=2012ApJ...761..123S 2012ApJ...761..123S
ADC_Keywords: Stars, double and multiple ; Photometry, ugriz ; Radial velocities
Keywords: planetary systems ; stars: individual (KELT-1, TYC 2785-2130-1);
techniques: photometric; techniques: spectroscopic
Abstract:
We present the discovery of KELT-1b, the first transiting low-mass
companion from the wide-field Kilodegree Extremely Little
Telescope-North (KELT-North) transit survey. A joint analysis of the
spectroscopic, radial velocity, and photometric data indicates that
the V=10.7 primary is a mildly evolved mid-F star with
Teff=6516±49K, logg=4.228+0.014-0.021, and
[Fe/H]=0.052±0.079, with an inferred mass M*=1.335±0.063M☉
and radius R*=1.471+0.045-0.035R☉. The companion is a
low-mass brown dwarf or a super-massive planet with mass
MP=27.38±0.93MJup and radius RP=1.116+0.038-0.029RJup.
The companion is on a very short (∼29 hr) period circular orbit, with
an ephemeris Tc (BJDTDB)=2455909.29280±0.00023 and
P=1.217501±0.000018 days. KELT-1b receives a large amount of stellar
insolation, resulting in an estimated equilibrium temperature assuming
zero albedo and perfect redistribution of Teq=2423+34-27K.
Comparison with standard evolutionary models suggests that the radius
of KELT-1b is likely to be significantly inflated. Adaptive optics
imaging reveals a candidate stellar companion to KELT-1 with a
separation of 588±1mas, which is consistent with an M dwarf if it is
at the same distance as the primary. Rossiter-McLaughlin measurements
during transit imply a projected spin-orbit alignment angle
λ=2±16deg, consistent with a zero obliquity for KELT-1.
Finally, the vsinI*=56±2km/s of the primary is consistent at
∼2σ with tidal synchronization. Given the extreme parameters of
the KELT-1 system, we expect it to provide an important testbed for
theories of the emplacement and evolution of short-period companions,
as well as theories of tidal dissipation and irradiated brown dwarf
atmospheres.
Description:
We obtained high-precision follow-up photometry of KELT-1 with 6
different telescopes during 2011 Dec and 2012 Jan. We chose to include
only a subset of all observations for the final analysis, including
six transits and the three secondary eclipses. The light curves for
the transits are displayed in Figure 5 and the data are listed in
Tables 9-14, whereas the light curves for the secondary eclipse are
displayed in Figure 6 and the data are listed in Tables 15-17. The
combined and binned transit light curve is shown in Figure 7.
A total of 81 spectra of KELT-1 were taken using the TRES spectrograph
on the 1.5m Tillinghast Reflector at FLWO with R∼44000 for a bandpass
of 3900-8900Å. The RV and bisector data for the RM (RM effect:
Rossiter 1924; McLaughlin 1924) run on UT 2012 January 7 are listed in
Table 8. The RV and bisector data for 23 spectra are listed in Table
7. These observations span ∼88 days from UT 2011 November 9 through UT
2012 February 5.
Objects:
-----------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
-----------------------------------------------------------------
00 01 26.92 +39 23 01.7 KELT-1 = TYC 2785-2130-1 (1.2175)
-----------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table7.dat 42 23 KELT-1 RM radial velocities and bisectors with TRES
at FLWO on nights outside of transit
table8.dat 42 42 KELT-1 RM radial velocities and bisectors with TRES
at FLWO on the night of the transit on UT 2012-01-07
table9.dat 30 151 Relative photometry from PvdKO on UT 2011-12-03 (i)
table10.dat 30 110 Relative photometry from ULMO on UT 2011-12-03 (r)
table11.dat 30 266 Relative photometry from HAO on UT 2011-12-10 (i)
table12.dat 30 362 Relative photometry from FLWO on UT 2011-12-16 (z)
table13.dat 30 162 Relative photometry from ULMO on UT 2011-12-31 (r)
table14.dat 30 459 Relative photometry from FLWO on UT 2012-01-07 (i)
table15.dat 30 115 Relative photometry from ULMO on UT 2011-12-02 (i)
table16.dat 30 72 Relative photometry from FTN/LCOGT on UT 2011-12-30
(PS-Z)
table17.dat 30 121 Relative photometry from ULMO on UT 2012-01-04 (i)
--------------------------------------------------------------------------------
See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/ApJ/753/156 : T/Y brown dwarfs with WISE photometry (Kirkpatrick+, 2012)
J/PASP/123/412 : Exoplanet Orbit Database (Wright+, 2011)
J/ApJ/663/573 : Sloan gi light curves of HAT-TR-205-012 (Beatty+, 2007)
J/AJ/128/1761 : HATNET variability survey (Hartman+, 2004)
Byte-by-byte Description of file: table[78].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 --- BJD Barycentric Julian Date; TDB (1)
16- 23 F8.1 m/s RV [-18414/-9968] Radial velocity (2)
25- 29 F5.1 m/s e_RV [93/367] RV uncertainty (2)
31- 36 F6.1 m/s BS [-699.1/267] Bisector span
38- 42 F5.1 m/s e_BS [46/413] BS uncertainty
--------------------------------------------------------------------------------
Note (1): Times are for mid-exposure and are in the BJDTDB standard
(Eastman et al. 2010PASP..122..935E 2010PASP..122..935E).
Note (2): RVs are approximately on an absolute scale, and the uncertainties have
been scaled based on a global fit to the data. See Sections 3.3 and
5.2 for details.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat table1[0-7].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d BJD Barycentric Julian Date; TDB
16- 22 F7.5 --- RFlux [0.985/1.008] Relative flux (1)
24- 30 F7.5 --- e_RFlux Uncertainty in RFlux
--------------------------------------------------------------------------------
Note (1): This photometry has been corrected for a linear trend with airmass,
and normalized by the fitted out-of-transit flux. See Section 5.2.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Aug-2014