J/AJ/153/211 Differential photometry of the F-subgiant HAT-P-67 (Zhou+, 2017)
HAT-P-67b: an extremely low density Saturn transiting an F-subgiant confirmed
via Doppler tomography.
Zhou G., Bakos G.A., Hartman J.D., Latham D.W., Torres G., Bhatti W.,
Penev K., Buchhave L., Kovacs G., Bieryla A., Quinn S., Isaacson H.,
Fulton B.J., Falco E., Csubry Z., Everett M., Szklenar T., Esquerdo G.,
Berlind P., Calkins M.L., Beky B., Knox R.P., Hinz P., Horch E.P.,
Hirsch L., Howell S.B., Noyes R.W., Marcy G., de Val-Borro M., Lazar J.,
Papp I., Sari P.
<Astron. J., 153, 211-211 (2017)>
=2017AJ....153..211Z 2017AJ....153..211Z (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, F-type ; Photometry, RI ; Photometry, SDSS
Keywords: planetary systems - stars: individual: HAT-P-67 -
techniques: photometric - techniques: spectroscopic
Abstract:
We report the discovery of HAT-P-67b, which is a hot-Saturn transiting
a rapidly rotating F-subgiant. HAT-P-67b has a radius of
Rp=2.085-0.071+0.096 RJ, and orbites a
M*=1.642-0.072+0.155 M☉, R*=2.546-0.084+0.099 R☉
host star in a ∼4.81 day period orbit. We place an upper limit on the
mass of the planet via radial velocity measurements to be Mp<0.59 MJ,
and a lower limit of >0.056 MJ by limitations on Roche lobe overflow.
Despite being a subgiant, the host star still exhibits relatively
rapid rotation, with a projected rotational velocity of
vsini*=35.8±1.1 km/s, which makes it difficult to precisely
determine the mass of the planet using radial velocities. We validated
HAT-P-67b via two Doppler tomographic detections of the planetary
transit, which eliminate potential eclipsing binary blend scenarios.
The Doppler tomographic observations also confirm that HAT-P-67b has
an orbit that is aligned to within 12°, in projection, with the
spin of its host star. HAT-P-67b receives strong UV irradiation and is
among one of the lowest density planets known, which makes it a good
candidate for future UV transit observations in the search for an
extended hydrogen exosphere.
Description:
The transits of HAT-P-67b were first detected with the HATNet survey
(Bakos et al. 2004PASP..116..266B 2004PASP..116..266B). HATNet employs a network of small,
wide field telescopes, located at the Fred Lawrence Whipple Observatory
(FLWO) in Arizona and at the Mauna Kea Observatory (MKO) in Hawaii, to
photometrically monitor selected 8x8° fields of the sky. A total
of 4050 I band observations were taken by HAT-5 and HAT-8 from 2005
January to July, and an additional 4518 observations were obtained in
the Cousins R band using HAT-5, HAT-7, and HAT-8 telescopes between
2008 February and August.
To better characterize the planetary properties, follow-up photometry
of the transits were obtained using the KeplerCam on the FWLO 1.2 m
telescope. KeplerCam is a 4Kx4K CCD camera with a pixel scale of
0.672"/pixel at 2x2 pixel binning. The photometry was reduced as per
Bakos et al. (2010, J/ApJ/710/1724). A full transit was observed in the
Sloan-i band on 2012 May 28, and five partial transits were observed
on 2011 April 15, May 19, June 07, and 2013 April 25 in the Sloan-i band,
and 2013 May 24 in the Sloan-z band.
Objects:
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RA (ICRS) DE Designation(s)
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18 18 58.42 +10 35 50.1 HAT-P-67 = TYC 1014-973-1
18 18 58.43 +10 35 50.1 HAT-P-67b = HAT-P-57b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 56 12696 Differential photometry of HAT-P-67
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See also:
J/AJ/128/1761 : HATNET variability survey (Hartman+, 2004)
J/ApJ/704/1107 : Transiting planet candidates in HATNet field 205
(Latham+, 2009)
J/ApJ/710/1724 : Follow-up photometry for HAT-P-11 (Bakos+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d BJD Barycentric Julian Date
15- 22 F8.5 mag Rawmag [8.74225/10.2706] Raw magnitude in Filter (1)
24- 30 F7.5 mag EPDmag [9.45495/9.75242]? External Parameter
Decorralation magnitude in Filter (1)
32- 38 F7.5 mag TFAmag [9.46132/9.74198]? Trend Filtering Algorithm
magnitude in Filter (1)
40- 46 F7.5 mag e_mag [0.00048/0.01417] Uncertainty in the magnitude
48- 54 A7 --- Inst Instrument used (HATNet or FLWO1.5)
56 A1 --- Filter [RIiz] Filter used
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Note (1): Raw, EPD, and TFA magnitudes are presented for HATNet light curves.
The detrending and potential blending may cause the HATNet transit
to be shallower than the true transit in the EPD and TFA light curves.
This is accounted for in the global modelling by the inclusion of a
third light factor. Follow-up light curves have been treated with
EPD simultaneous to the transit fitting. Pre-EPD magnitudes are
presented for the follow-up light curves.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 27-Apr-2018