J/ApJ/750/84 Follow-up photometry and velocity of Qatar 2 (Bryan+, 2012)
Qatar-2: a K dwarf orbited by a transiting hot Jupiter and a more massive
companion in an outer orbit.
Bryan M.L., Alsubai K.A., Latham D.W., Parley N.R., Collier Cameron A.,
Quinn S.N., Carter J.A., Fulton B.J., Berlind P., Brown W.R.,
Buchhave L.A., Calkins M.L., Esquerdo G.A., Furesz G., Jorgensen U.G.,
Horne K.D., Stefanik R.P., Street R.A., Torres G., West R.G., Dominik M.,
Harpsoe K.B.W., Liebig C., Calchi Novati S., Ricci D., Skottfelt J.F.
<Astrophys. J., 750, 84 (2012)>
=2012ApJ...750...84B 2012ApJ...750...84B
ADC_Keywords: Planets ; Stars, double and multiple ; Radial velocities ;
Photometry, VRI
Keywords: planetary systems - stars: individual: (Qatar-2) -
techniques: photometric - techniques: radial velocities -
techniques: spectroscopic
Abstract:
We report the discovery and initial characterization of Qatar-2b, a
hot Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with
a short period, Pb= 1.34 days. The mass and radius of Qatar-2b are
MP = 2.49 MJ and RP= 1.14 RJ, respectively. Radial-velocity
monitoring of Qatar-2 over a span of 153 days revealed the presence of
a second companion in an outer orbit. The Systemic Console yielded
plausible orbits for the outer companion, with periods on the order of
a year and a companion mass of at least several MJ. Thus, Qatar-2
joins the short but growing list of systems with a transiting hot
Jupiter and an outer companion with a much longer period. This system
architecture is in sharp contrast to that found by Kepler for
multi-transiting systems, which are dominated by objects smaller than
Neptune, usually with tightly spaced orbits that must be nearly
coplanar.
Description:
We monitored the spectrum of Qatar-2 using the Tillinghast Reflector
Echelle Spectrograph (TRES), mounted on the 1.5 m Tillinghast
Reflector at the Fred L. Whipple Observatory on Mount Hopkins,
Arizona. Over a period of 153 days from 2011 January 18 to June 21 we
obtained 44 spectra with a signal-to-noise ratio per resolution
element (SNRe) of at least 20 in the continuum at the center of the
order containing the Mg b features (near 518 nm). We used the medium
fiber, which yields a resolving power of R∼44000.
Light curves for four transits of Qatar-2b were obtained by use of
KeplerCam on the 1.2 m telescope at the Fred Lawrence Whipple
Observatory on Mount Hopkins, Arizona. We observed transit events of
Qatar-2b on the nights of 2011 February 26, 2011 March 6, 2011 March
14, and 2011 March 18. A Sloan Digital Sky Survey (SDSS) i-band filter
was used for three of the transits, and an SDSS g-band filter was used
for the fourth.
Four partial transit events were observed with a 0.8 m telescope
operated by the Las Cumbres Observatory Global Telescope (LCOGT) at
the Byrne Observatory at Sedgwick Reserve near Santa Ynez, CA. We
observed in the SDSS r band with exposure times of 120 s.
The 400 mm focal length Canon lenses used by the QES cameras produce
images with a typical FWHM of 7.5". To push to even lower limits, we
obtained high-resolution images with the Danish 1.54m telescope at
the European Southern Observatory on La Silla (See section 5).
Objects:
------------------------------------------------------------------------
RA (2000) DE Designation(s) (Qatar-2b period)
------------------------------------------------------------------------
13 50 37.41 -06 48 14.4 Qatar 2 = GSC 04974-00112 (P=1.34)
------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 43 44 Relative radial velocities of Qatar-2
table5.dat 47 1952 Light curves for the transits of Qatar-2b
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See also:
J/A+A/556/A150 : SWEETCat I. Stellar parameters for host stars (Santos+, 2013)
J/A+A/552/A119 : Planet-star and moon-planet interaction (Saur+, 2013)
J/PASP/123/412 : Exoplanet Orbit Database (Wright+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Barycentric Julian Date
16- 21 F6.1 m/s RV Radial velocity (1)
23- 26 F4.1 m/s e_RV The 1σ error in RV (2)
28- 32 F5.1 m/s BS Bisector span (3)
34- 37 F4.1 m/s e_BS The 1σ error in BS
39- 43 F5.1 m/s cRV Zero point correction
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Note (1): The zero-point of these velocities is relative to the observation
obtained on BJD 2455646. The absolute velocity of that observation
on the IAU system is -23.8±0.1km/s.
Note (2): Internal errors, summed in quadrature with the uncertainty of the
run-to-run zero point shifts, assumed to be 5m/s.
Note (3): The zero point of the bisector spans is arbitrary.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d BJD Barycentric Julian Date
18- 26 F9.6 mag mag Relative Filt magnitude
28- 35 F8.6 mag e_mag Uncertainty in mag
37- 45 A9 --- Inst Instrument used in observation (KeplerCam,
LCOGT or QES)
47 A1 --- Filt [grRi] Filter used in observation (g, i, r or R)
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History:
From electronic version of the journal (Supplemental data file tar.gz)
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Dec-2013