J/MNRAS/491/2834 NGTS-8b and NGTS-9b non-inflated hot Jupiters (Costes+, 2020)
NGTS-8b and NGTS-9b: two non-inflated hot Jupiters.
Costes J.C., Watson C.A., Belardi C., Braker I.P., Burleigh M.R.,
Casewell S.L., Eigmuller P., Gunther M.N., Jackman J.A.G., Nielsen L.D.,
Soto M.G., Turner O., Anderson D.R., Bayliss D., Bouchy F., Briegal J.T.,
Bryant E.M., Cabrera J., Chaushev A., Csizmadia S., Erikson A., Gill S.,
Gillen E., Goad M.R., Hodgkin S., Hooton M.J., Jenkins J.S., McCormac J.,
Moyano M., Queloz D., Rauer H., Raynard L., Smith A.M.S., Thompson A.P.G.,
Tilbrook R.H., Udry S., Vines J.I., West R.G., Wheatley P.J.
<Mon. Not. R. Astron. Soc., 491, 2834-2844 (2020)>
=2020MNRAS.491.2834C 2020MNRAS.491.2834C (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Photometry ; Spectra, optical ; Stars, masses ;
Stars, diameters ; Effective temperatures ;
Parallaxes, trigonometric ; Proper motions ; Radial velocities ;
Stars, ages
Keywords: techniques: photometric - planets and satellites: detection -
stars: individual: NGTS-8 and NGTS-9 - planetary systems
Abstract:
We report the discovery, by the next generation transit survey (NGTS),
of two hot Jupiters NGTS-8b and NGTS-9b. These orbit a V=13.68 K0V
star (Teff=5241±50K) with a period of 2.49970d, and a V=12.80 F8V
star (Teff=6330±130K) in 4.43527d, respectively. The transits were
independently verified by follow-up photometric observations with the
South African Astronomical Observatory 1.0-m and Euler telescopes, and
we report on the planetary parameters using HARPS, FEROS, and CORALIE
radial velocities. NGTS-8b has a mass, 0.93+0.04-0.03MJ and a
radius, 1.09±0.03RJ similar to Jupiter, resulting in a density of
0.89+0.08-0.07gcm-3. This is in contrast to NGTS-9b, which has a
mass of 2.90±0.17MJ and a radius of 1.07±0.06RJ, resulting in
a much greater density of 2.93+0.53-0.49gcm-3. Statistically,
the planetary parameters put both objects in the regime where they
would be expected to exhibit larger than predicted radii. However, we
find that their radii are in agreement with predictions by theoretical
non-inflated models.
Description:
The next generation transit survey (NGTS), operating since early 2016,
is a widefield transit survey located at ESO's Paranal Observatory in
Chile, whose primary goal is to discover Neptune-sized or bigger
exoplanets. For a description of this facility and its capabilities,
we refer the reader to Wheatley et al. (2018MNRAS.475.4476W 2018MNRAS.475.4476W). NGTS has
already detected four hot Jupiters, here, we report the latest
hot-Jupiter discoveries from NGTS: NGTS-8b and NGTS-9b.
NGTS-8 was observed using a single NGTS camera (#811) over a 227 night
baseline between the 2016 April 21 and the 2016 December 3. NGTS-9 was
also observed using a single camera (#806) over a 234 night baseline
between the 2016 October 8 and the 2017 May 29.
Follow-up photometry of NGTS-8 was obtained with the 1.0m Elizabeth
telescope at the South African Astronomical Observatory (SAAO) on 2017
July 17 and 2017 July 18, utilizing the frame-transfer CCD Sutherland
High-speed Optical Camera 'SHOC'n'awe' (SHOC; Coppejans et al.
2013PASP..125..976C 2013PASP..125..976C). We also obtained two follow-up light curves of
NGTS-9 on 2018 December 21 and 2019 January 30.
We also observed both objects with Eulercam (Lendl et al.
2012A&A...544A..72L 2012A&A...544A..72L, Cat. J/A+A/544/A72) on the 1.2m Euler Telescope
at La Silla Observatory. NGTS-8 was observed on the 2017 August 21 and
NGTS-9 was observed on the 2019 January 12.
Finally, NGTS-8 was observed with the HARPS spectrograph (Mayor et al.
2003Msngr.114...20M 2003Msngr.114...20M) on the ESO 3.6m telescope at La Silla
Observatory, Chile, between the 2017 August 5 and the 2017 October 28
under programmes 099.C-0303 and 0100.C-0474. Three additional spectra
were obtained with FEROS (Kaufer & Pasquini 1998SPIE.3355..844K 1998SPIE.3355..844K),
mounted on the MPG 2.2m telescope at La Silla Observatory, Chile, on
the 2017 August 20 and 21.
NGTS-9 was observed with the CORALIE spectrograph (Queloz et al.
2001Msngr.105....1Q 2001Msngr.105....1Q) on the 1.2m Euler telescope at La Silla
Observatory, Chile, between the 2017 December 24 and the 2018 April 5.
Objects:
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RA (ICRS) DE Designation(s)
----------------------------------------------------------------
21 55 54.19 -14 04 06.2 NGTS-8 = 2MASS J21555419-1404062
09 27 40.96 -19 20 51.5 NGTS-9 = 2MASS J09274096-1920515
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 383 1 Stellar Properties for NGTS-8
table7.dat 383 1 Stellar Properties for NGTS-9
table1.dat 44 178298 Photometric data of NGTS-8 from NGTS, SAAO, and
Eulercam
table2.dat 44 167375 Photometric data of NGTS-9 from NGTS, SAAO, and
Eulercam
table4.dat 52 14 HARPS and FEROS radial velocities for NGTS-8
table5.dat 54 16 CORALIE radial velocities for NGTS-9
table8.dat 183 1 Planetary properties for NGTS-8b using
allesfitter
table9.dat 183 1 Planetary properties for NGTS-9b using
allesfitter
table10.dat 85 2 A summary of the mass-radius model for NGTS-8b
with radius 1.09±0.03RJ
table11.dat 85 2 A summary of the mass-radius model for NGTS-9b
with radius 1.07±0.06RJ
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/615/A76 : Spectroscopic parameters of stars (SPECIES). I. (Soto+, 2018)
Byte-by-byte Description of file: table6.dat table7.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name (NGTS-8 or NGTS-9)
8- 9 I2 h RAh Right ascension (J2000) (1)
11- 12 I2 min RAm Right ascension (J2000) (1)
14- 17 F4.1 s RAs Right ascension (J2000) (1)
19 A1 --- DE- Declination sign (J2000) (1)
20- 21 I2 deg DEd Declination (J2000) (1)
23- 24 I2 arcmin DEm Declination (J2000) (1)
26- 30 F5.2 arcsec DEs Declination (J2000) (1)
32- 47 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs) (1)
49- 67 I19 --- GaiaDR2 Gaia DR2 source identifier (2)
69- 74 F6.3 mas/yr pmRA Proper motion in right ascension (2)
76- 80 F5.3 mas/yr e_pmRA Error on pmRA (2)
82- 88 F7.3 mas/yr pmDE Proper motion in declination (2)
90- 94 F5.3 mas/yr e_pmDE Error on pmDE (2)
96-101 F6.4 mas plx Parallax (2)
103-108 F6.4 mas e_plx Error on plx (2)
110-114 F5.2 mag Vmag APASS V-band magnitude (3)
116-119 F4.2 mag e_Vmag Error on Vmag (3)
121-125 F5.2 mag Bmag APASS B-band magnitude (3)
127-130 F4.2 mag e_Bmag Error on Bmag (3)
132-136 F5.2 mag gmag APASS g-band magnitude (3)
138-141 F4.2 mag e_gmag Error on gmag (3)
143-147 F5.2 mag rmag APASS r-band magnitude (3)
149-152 F4.2 mag e_rmag Error on rmag (3)
154-158 F5.2 mag imag APASS i-band magnitude (3)
160-163 F4.2 mag e_imag Error on imag (3)
165-171 F7.4 mag Gmag Gaia DR2 G magnitude (2)
173-178 F6.4 mag e_Gmag Error on Gmag (2)
180-186 F7.4 mag RPmag Gaia DR2 RP magnitude (2)
188-193 F6.4 mag e_RPmag Error on RPmag (2)
195-201 F7.4 mag BPmag Gaia DR2 BP magnitude (2)
203-208 F6.4 mag e_BPmag Error on BPmag (2)
210-214 F5.2 mag Jmag 2MASS J-band magnitude (1)
216-219 F4.2 mag e_Jmag Error on Jmag (1)
221-225 F5.2 mag Hmag 2MASS H-band magnitude (1)
227-230 F4.2 mag e_Hmag Error on Hmag (1)
232-236 F5.2 mag Kmag 2MASS K-band magnitude (1)
238-241 F4.2 mag e_Kmag Error on Kmag (1)
243-247 F5.2 mag W1mag WISE W1 (3.4um) band magnitude (4)
249-252 F4.2 mag e_W1mag Error on W1mag (4)
254-258 F5.2 mag W2mag WISE W2 (4.6um) band magnitude (4)
260-263 F4.2 mag e_W2mag Error on W2mag (4)
265-269 F5.2 mag W3mag WISE W3 (12um) band magnitude (4)
271-274 F4.2 mag e_W3mag Error on W3mag (4)
276-278 A3 --- SpType Spectral type (2)
280-283 I4 K Teff Effective temperature (5)
285-287 I3 K e_Teff Error on Teff (5)
289-292 F4.2 [-] [Fe/H] Fe/H abundance ratio (5)
294-297 F4.2 [-] e_[Fe/H] Error on [Fe/H] (5)
299-302 F4.2 km/s vsini Projected rotational velocity (5)
304-307 F4.2 km/s e_vsini Error on vsini (5)
309-312 F4.2 km/s vmac Macroturbulent velocity (5)
314-317 F4.2 km/s e_vmac Error on vmac (5)
319-322 F4.2 [cm/s2] logg Surface gravity (5)
324-327 F4.2 [cm/s2] e_logg Error on logg (5)
329-332 F4.2 Msun Mass Star mass (5)
334-337 F4.2 Msun E_Mass Upper error on Mass (5)
339-342 F4.2 Msun e_Mass Lower error on Mass (5)
344-347 F4.2 Rsun Rad Star radius (5)
349-352 F4.2 Rsun e_Rad Error on Rad (5)
354-358 F5.2 Gyr Age Star age (5)
360-363 F4.2 Gyr E_Age Upper error on Age (5)
365-368 F4.2 Gyr e_Age Lower error on Age (5)
370-376 F7.3 pc Dist Distance (2)
378-383 F6.3 pc e_Dist Error on Dist (2)
--------------------------------------------------------------------------------
Note (1): Values from 2MASS (Skrutskie et al. 2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233)
Note (2): Values from Gaia DR2 (Gaia Collaboration 2018A&A...616A...1G 2018A&A...616A...1G,
Cat. I/345)
Note (3): Values from APASS (Henden & Munari 2014CoSka..43..518H 2014CoSka..43..518H)
Note (4): Values from WISE (Wright et al. 2010AJ....140.1868W 2010AJ....140.1868W)
Note (5): Values obtained using SPECIES (Soto & Jenkins 2018A&A...615A..76S 2018A&A...615A..76S,
Cat. J/A+A/615/A76)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d BJD Barycentric Julian Date
18- 27 F10.8 --- RFlux Relative flux
29- 38 F10.8 --- e_RFlux Error on RFlux
40- 44 A5 --- Inst Instrument used for the observations (1)
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Note (1): Instrument as follows:
Euler = 502/178298 fluxes
NGTS = 177120/178298 fluxes
SAAO = 676/178298 fluxes
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 F16.8 d BJD Barycentric Julian Date
18- 27 F10.8 --- RFlux Relative flux7
29- 38 F10.8 --- e_RFlux Error on RFlux
40- 44 A5 --- Inst Instrument used for the observations (1)
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Note (1): Instrument as follows:
Euler = 134/167375 fluxes
NGTS = 166043/167375 fluxes
SAAO = 1198/167375 fluxes
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Byte-by-byte Description of file: table4.dat table5.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d JDB Julian Date (-2400000)
12- 18 F7.4 km/s RV Radial velocity
20- 25 F6.4 km/s e_RV Error on RV
27- 33 F7.4 km/s FWHM Full width at half maximum
35- 41 F7.4 km/s BIS Bisector inverse slope
43- 46 I4 s ExpTime Exposure time
48- 54 A7 --- Inst Instrument used
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Byte-by-byte Description of file: table8.dat table9.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Planet name (NGTS-8b or NGTS-9b)
9- 15 F7.5 d Period Orbital period
17- 23 F7.5 d e_Period Error on Period
25- 37 F13.5 d TC Transit center time in BJD
39- 45 F7.5 d e_TC Error on TC
47- 50 F4.2 h T14 Duration of transit (1st to 4th contact) T14
52- 55 F4.2 h e_T14 Error on T14
57- 60 F4.2 --- a/Rs Semi-major axis to star radii ratio
62- 65 F4.2 --- e_a/Rs Error on a/Rs
67- 71 F5.3 --- R/Rs Planet to star radii ratio
73- 77 F5.3 --- e_R/Rs Error on R/Rs
79- 84 F6.2 m/s K Radial velocity semi-amplitude
86- 90 F5.2 m/s e_K Error on K
92- 96 F5.3 --- e Eccentricity
98-102 F5.3 --- E_e Upper error on e
104-108 F5.3 --- e_e Lower error on e
110-113 F4.1 deg inc Inclination of the orbit
115-117 F3.1 deg e_inc Error on inc
119-122 F4.2 Mjup Mp Planet mass
124-127 F4.2 Mjup E_Mp Upper error on Mp
129-132 F4.2 Mjup e_Mp Lower error on Mp
134-137 F4.2 Rjup Rp Planet radius
139-142 F4.2 Rjup e_Rp Error on Rp
144-147 F4.2 g/cm3 rhop Planet density
149-152 F4.2 g/cm3 E_rhop Upper error on rhop
154-157 F4.2 g/cm3 e_rhop Lower error on rhop
159-163 F5.3 AU a Semi-major axis
165-169 F5.3 AU E_a Upper error on a
171-175 F5.3 AU e_a Lower error on a
177-180 I4 K Teq Planet equilibrium temperature
182-183 I2 K e_Teq Error on Teq
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Byte-by-byte Description of file: table10.dat table11.dat
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Bytes Format Units Label Explanations
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1- 36 A36 --- Model Mass-radius model used
38- 41 A4 Mjup Mp Minimum mass of the planet
43- 47 F5.3 AU Sep Orbital separation
49- 52 F4.2 Gyr Agemin Age range of the system (minimum value or
value if no maximum indicated)
54- 58 F5.2 Gyr Agemax ? Age range of the system (maximum value)
60- 63 F4.2 --- fMassmin ? Minimum mass fraction of heavy material
65- 67 F3.1 --- fMassmax ? Maximum mass fraction of heavy material
69 I1 % Mcoremin ? Minimum core mass
71- 73 I3 % Mcoremax ? Maximum core mass
75- 79 F5.3 Rjup Rpmin Minimum planet radius
81- 85 F5.3 Rjup Rpmax Maximum planet radius
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 16-Feb-2023