J/MNRAS/496/4330 A 55-d period dense Neptune transiting HD 95338 (Diaz+, 2020)
The Magellan/PFS Exoplanet Search: a 55-d period dense Neptune transiting the
bright (V=8.6) star HD 95338.
Diaz M.R., Jenkins J.S., Feng F., Butler R.P., Tuomi M., Shectman S.A.,
Thorngren D., Soto M.G., Vines J.I., Teske J.K., Dragomir D.,
Villanueva S., Kane S.R., Berdinas Z.M., Crane J.D., Wang S.X.,
Arriagada P.
<Mon. Not. R. Astron. Soc., 496, 4330-4341 (2020)>
=2020MNRAS.496.4330D 2020MNRAS.496.4330D (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Milky Way ; Radial velocities ; Stars, masses ;
Stars, diameters ; Optical
Keywords: techniques: photometric - techniques: radial velocities -
planets and satellites: detection -
planets and satellites: fundamental parameters - planetary systems
Abstract:
We report the detection of a transiting, dense Neptune planet
candidate orbiting the bright (V=8.6) K0.5V star HD 95338. Detection of
the 55-d periodic signal comes from the analysis of precision radial
velocities from the Planet Finder Spectrograph on the Magellan II
Telescope. Follow-up observations with HARPS also confirm the presence
of the periodic signal in the combined data. HD 95338 was also observed
by the Transiting Exoplanet Survey Satellite (TESS) where we identify
a clear single transit in the photometry. A Markov chain Monte Carlo
period search on the velocities allows strong constraints on the
expected transit time, matching well the epoch calculated from TESS
data, confirming both signals describe the same companion. A joint fit
model yields an absolute mass of 42.44+2.22-2.08M⊕ and a
radius of 3.89+0.19-0.20R⊕, which translates into a
density of 3.98+0.62-0.64g/cm3 for the planet. Given the planet
mass and radius, structure models suggest it is composed of a mixture
of ammonia, water, and methane. HD 95338 b is one of the most dense
Neptune planets yet detected, indicating a heavy element enrichment of
∼90 per cent (∼38M⊕). This system presents a unique
opportunity for future follow-up observations that can further
constrain structure models of cool gas giant planets.
Description:
High-precision Doppler measurements of HD 95338 were acquired using
PFS mounted on the 6.5-m Magellan II (Clay) telescope at Las Campanas
Observatory, and the High Accuracy Radial velocity Planet Searcher
(HARPS; Pepe et al. 2002Msngr.110....9P 2002Msngr.110....9P) installed on the ESO 3.6-m
telescope at La Silla Observatory.
Observations were carried out using PFS between 2010 February 26 and
2018 May 25, as part of the Magellan Exoplanet Long Term Survey (LTS).
Fifty two observations were acquired using an average of 540s of
exposure time.
PFS was upgraded with a new CCD detector in 2017. The new CCD is a
10kx10k sensor and has smaller pixels. The data using this new setup
are labelled as PFS2 and include 31 observations.
The radial velocities are computed with a custom pipeline following
the procedure outlined by Butler et al. (1996PASP..108..500B 1996PASP..108..500B). They
are listed in Tables 1 and 2.
Eleven observations using HARPS were acquired between 2018 May 24 and
2019 April 6 from program IDs 0101.C-0497, 0102.C-0525, and
0103.C-0442 (PI: Diaz), in order to confirm the signal found in PFS
data and also to constrain the orbital parameters of the planet
candidate. We re-processed the observations with the terra software
(Anglada-Escude & Butler 2012ApJS..200...15A 2012ApJS..200...15A, Cat. J/ApJS/200/15).
Objects:
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RA (ICRS) DE Designation(s)
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10 59 26.30 -56 37 22.9 TIC 304142124 = 2MASS J10592629-5637229
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 50 PFS1 radial velocities of HD 95338
table2.dat 45 31 PFS2 radial velocities of HD 95338
table3.dat 97 11 TERRA Radial Velocities of HD 95338
table4.dat 335 1 Stellar Parameters of HD 95338
table6.dat 207 1 Posterior for the parameters included in the
RV-only analysis
table8.dat 430 1 Planetary properties for HD 95338b
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d BJD Barycentric Julian Date
15- 23 F9.5 m/s RV Radial velocity
25- 31 F7.5 m/s e_RV Error on RV
33- 39 F7.5 --- S S-index (G1)
41- 45 F5.3 --- e_S Error on S
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 F16.8 --- BJD Barycentric Julian Date
18- 36 F19.16 m/s RV Radial velocity
38- 55 F18.16 m/s e_RV Error on RV
57- 75 F19.17 --- S S-index (G1)
77- 97 F21.19 --- e_S Error on S
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Source name in the TESS catalogue
(TIC 304142124)
15- 16 I2 h RAh Right ascension (J2000)
18- 19 I2 min RAm Right ascension (J2000)
21- 26 F6.3 s RAs Right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd Declination (J2000)
32- 33 I2 arcmin DEm Declination (J2000)
35- 40 F6.3 arcsec DEs Declination (J2000)
42- 47 F6.4 mag Tmag TESS magnitude from ExoFOP
(https://exofop.ipac.caltech.edu/tess/)
49- 54 F6.4 mag e_Tmag Error on Tmag
56- 60 F5.3 mag Hmag 2MASS H-band magnitude
62- 66 F5.3 mag e_Hmag Error on Hmag
68- 72 F5.3 mag Jmag 2MASS J-band magnitude
74- 78 F5.3 mag e_Jmag Error on Jmag
80- 84 F5.3 mag Ksmag 2MASS Ks-band magnitude
86- 90 F5.3 mag e_Ksmag Error on Ksmag
92- 96 F5.3 mag Vmag V-band magnitude from Simbad
98- 102 F5.3 mag e_Vmag Error on Vmag
104- 108 F5.3 mag Bmag B-band magnitude from Simbad
110- 114 F5.3 mag e_Bmag Error on Bmag
116- 121 F6.4 mag Gmag Gaia DR2 G-band magnitude
123- 128 F6.4 mag e_Gmag Error on Gmag
130- 135 F6.4 mag RPmag Gaia DR2 RP-band magnitude
137- 142 F6.4 mag e_RPmag Error on RPmag
144- 149 F6.4 mag BPmag Gaia DR2 BP-band magnitude
151- 155 F5.3 mag e_BPmag Error on BPmag
157- 161 F5.3 mag W1mag WISE W1 (3.4um) band magnitude
163- 167 F5.3 mag e_W1mag Error on W1mag
169- 173 F5.3 mag W2mag WISE W2 (4.6um) band magnitude
175- 179 F5.3 mag e_W2mag Error on W2mag
181- 187 F7.4 mas plx Gaia DR2 parallax
189- 194 F6.4 mas e_plx Error on plx
196- 200 F5.2 pc Dist Distance (1)
202- 205 F4.2 pc E_Dist Upper error on Dist
207- 210 F4.2 pc e_Dist Lower error on Dist
212- 216 A5 --- SpType Spectral type derived using ARIADNE (1)
218- 221 F4.2 Msun Mass Star mass derived using ARIADNE (1)
223- 226 F4.2 Msun E_Mass Upper error on Mass
228- 231 F4.2 Msun e_Mass Lower error on Mass
233- 236 F4.2 Rsun Radius Star Radius derived using ARIADNE (1)
238- 241 F4.2 Rsun E_Radius Upper error on Radius
243- 246 F4.2 Rsun e_Radius Lower error on Radius
248- 251 F4.2 Gyr Age Star age derived using SPECIES (1)
253- 256 F4.2 Gyr e_Age Error on Age
258- 262 F5.3 mag Av Extinction derived using ARIADNE (1)
264- 268 F5.3 mag E_Av Upper error on Av
270- 274 F5.3 mag e_Av Lower error on Av
276- 279 F4.2 Lsun Lum Star luminosity from Anderson & Francis
(2012AstL...38..331A 2012AstL...38..331A, Cat. V/137)
281- 284 F4.2 Lsun e_Lum Error on Lum
286- 289 I4 K Teff Effective temperature derived using SPECIES
(1)
291- 292 I2 K E_Teff Upper error on Teff
294- 295 I2 K e_Teff Lower error on Teff
297- 300 F4.2 [-] [Fe/H] Fe/H abundance ratio derived using SPECIES (1)
302- 305 F4.2 [-] e_[Fe/H] Error on [Fe/H]
307- 310 F4.2 [cm/s2] logg Surface gravity derived using SPECIES (1)
312- 315 F4.2 [cm/s2] e_logg Error on logg
317- 320 F4.2 km/s vsini Rotational velocity derived using SPECIES (1)
322- 325 F4.2 km/s e_vsini Error on vsini
327- 330 F4.2 km/s vmac Macroturbulence velocity derived using
SPECIES (1)
332- 335 F4.2 km/s e_vmac Error on vmac
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Note (1): Value derived in this work
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.3 d Period Orbital period
8- 12 F5.3 d e_Period Error on Period
14- 22 F9.4 d Tperi Time of pericentre passage
24- 29 F6.4 d e_Tperi Error on Tperi
31- 34 F4.2 m/s K Velocity semiamplitude
36- 39 F4.2 m/s e_K Error on K
41- 45 F5.3 --- e Eccentricity
47- 51 F5.3 --- e_e Error on e
53- 58 F6.3 deg omega Longitude of pericentre
60- 65 F6.3 deg e_omega Error on omega
67- 73 F7.3 deg M0 Mean anomaly
75- 80 F6.3 deg e_M0 Error on M0
82- 86 F5.2 Mgeo Msini Minimum mass
88- 91 F4.2 Mgeo e_Msini Error on Msini
93- 97 F5.3 m/s muPFS1 Radial velocity zero-point for PFS1
99- 103 F5.3 m/s e_muPFS1 Error on muPFS1
105- 109 F5.3 m/s sigPFS1 Radial velocity jitter for PFS1
111- 115 F5.3 m/s e_sigPFS1 Error on sigPFS1
117- 121 F5.3 --- PhiPFS1 Moving average amplitude for PFS1
123- 127 F5.3 --- e_PhiPFS1 Error on PhiPFS1
129- 132 F4.2 --- lntauPFS1 Natural logarithm of the smoothing
time-scale for PFS1
134- 137 F4.2 --- e_lntauPFS1 Error on lntauPFS1
139- 143 F5.3 m/s muPFS2 Radial velocity zero-point for PFS2
145- 149 F5.3 m/s e_muPFS2 Error on muPFS2
151- 155 F5.3 m/s sigPFS2 Radial velocity jitter for PFS2
157- 161 F5.3 m/s e_sigPFS2 Error on sigPFS2
163- 167 F5.3 --- PhiPFS2 Moving average amplitude for PFS2
169- 173 F5.3 --- e_PhiPFS2 Error on PhiPFS2
175- 179 F5.3 --- lntauPFS2 Natural logarithm of the smoothing
time-scale for PFS2
181- 185 F5.3 --- e_lntauPFS2 Error on lntauPFS2
187- 191 F5.3 m/s muHARPS Radial velocity zero-point for HARPS
193- 197 F5.3 m/s e_muHARPS Error on muHARPS
199- 202 F4.2 m/s sigHARPS Radial velocity jitter for HARPS
204- 207 F4.2 m/s e_sigHARPS Error on sigHARPS
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 kg/m3 rho* Star density (1)
10- 15 F6.3 kg/m3 E_rho* Upper error on rho*
17- 22 F6.3 kg/m3 e_rho* Lower error on rho*
24- 29 F6.3 d P Orbital period (1)
31- 35 F5.3 d E_P Upper error on P
37- 41 F5.3 d e_P Lower error on P
43- 51 F9.4 d Tc Transit center (1)
53- 58 F6.4 d E_Tc Upper error on Tc
60- 65 F6.4 d e_Tc Lower error on Tc
67- 72 F6.3 --- a/R* Scaled semimajor axis (1)
74- 78 F5.3 --- E_a/R* Upper error on a/R*
80- 84 F5.3 --- e_a/R* Lower error on a/R*
86- 90 F5.3 --- b Impact parameter (1)
92- 96 F5.3 --- E_b Upper error on b
98- 102 F5.3 --- e_b Lower error on b
104- 107 F4.2 m/s K Velocity semiamplitude (1)
109- 112 F4.2 m/s E_K Upper error on K
114- 117 F4.2 m/s e_K Lower error on K
119- 123 F5.2 deg ip Inclination (1)
125- 128 F4.2 deg E_ip Upper error on ip
130- 133 F4.2 deg e_ip Lower error on ip
135- 139 F5.3 --- e Eccentricity (1)
141- 145 F5.3 --- E_e Upper error on e
147- 151 F5.3 --- e_e Lower error on e
153- 157 F5.2 deg omega Longitude of pericentre (1)
159- 163 F5.2 deg E_omega Upper error on omega
165- 169 F5.2 deg e_omega Lower error on omega
171- 175 F5.2 Mgeo Mp Planet mass (2)
177- 180 F4.2 Mgeo E_Mp Upper error on Mp
182- 185 F4.2 Mgeo e_Mp Lower error on Mp
187- 190 F4.2 Rgeo Rp Planet radius (2)
192- 195 F4.2 Rgeo E_Rp Upper error on Rp
197- 200 F4.2 Rgeo e_Rp Lower error on Rp
202- 206 F5.3 AU a Semimajor axis (2)
208- 212 F5.3 AU E_a Upper error on a
214- 218 F5.3 AU e_a Lower error on a
220- 223 F4.2 g/cm3 rhop Planet density (2)
225- 228 F4.2 g/cm3 E_rhop Upper error on rhop
230- 233 F4.2 g/cm3 e_rhop Lower error on rhop
235- 237 I3 K Teq Equilibrium temperature estimated using a
Bond albedo of 0.5 (2)
239- 240 I2 K E_Teq Upper error on Teq
242- 243 I2 K e_Teq Lower error on Teq
245- 248 F4.2 10+4W/m2 F Median flux (2)
250- 253 F4.2 10+4W/m2 e_F Error on F
255- 264 F10.7 ppm MTESS Relative flux offset for TESS (3)
266- 274 F9.7 ppm E_MTESS Upper error on MTESS
276- 284 F9.7 ppm e_MTESS Lower error on MTESS
286- 290 F5.3 ppm sigTESS Extra jitter term for TESS light curve (3)
292- 297 F6.3 ppm E_sigTESS Upper error on sigTESS
299- 303 F5.3 ppm e_sigTESS Lower error on sigTESS
305- 309 F5.3 --- q1TESS Quadratic limb-darkening parametrization
q1 (3)
311- 315 F5.3 --- E_q1TESS Upper error on q1TESS
317- 321 F5.3 --- e_q1TESS Lower error on q1TESS
323- 327 F5.3 --- q2TESS Quadratic limb-darkening parametrization
q2 (3)
329- 333 F5.3 --- E_q2TESS Upper error on q2TESS
335- 339 F5.3 --- e_q2TESS Lower error on q2TESS
341- 344 F4.2 m/s muPFS1 Radial velocity zero-point for PFS1 (3)
346- 349 F4.2 m/s E_muPFS1 Upper error on muPFS1
351- 354 F4.2 m/s e_muPFS1 Lower error on muPFS1
356- 359 F4.2 m/s sigPFS1 Radial velocity jitter for PFS1 (3)
361- 364 F4.2 m/s E_sigPFS1 Upper error on sigPFS1
366- 369 F4.2 m/s e_sigPFS1 Lower error on sigPFS1
371- 374 F4.2 m/s muHARPS Radial velocity zero-point for HARPS (3)
376- 379 F4.2 m/s E_muHARPS Upper error on muHARPS
381- 384 F4.2 m/s e_muHARPS Lower error on muHARPS
386- 389 F4.2 m/s sigHARPS Radial velocity jitter for HARPS (3)
391- 394 F4.2 m/s E_sigHARPS Upper error on sigHARPS
396- 399 F4.2 m/s e_sigHARPS Lower error on sigHARPS
401- 405 F5.2 m/s muPFS2 Radial velocity zero-point for PFS2 (3)
407- 410 F4.2 m/s E_muPFS2 Upper error on muPFS2
412- 415 F4.2 m/s e_muPFS2 Lower error on muPFS2
417- 420 F4.2 m/s sigPFS2 Radial velocity jitter for PFS2 (3)
422- 425 F4.2 m/s E_sigPFS2 Upper error on sigPFS2
427- 430 F4.2 m/s e_sigPFS2 Lower error on sigPFS2
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Note (1): Fitted parameters
Note (2): Derived parameters
Note (3): Instrumental parameters
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Global Notes:
Note (G1): The flux ratio of two bandpasses centered on the H (3968.5Å) and
K (3933.7Å) CaII emission cores and two continuum regions on
either side. The S-Index includes contributions from both the
photosphere and the chromosphere of the star.
S-indices are derived using the prescription outlined by
Baliunas, Sokoloff & Soon (1996ApJ...457L..99B 1996ApJ...457L..99B, Cat. J/ApJ/457/L99)
and Boisse et al. (2011A&A...528A...4B 2011A&A...528A...4B).
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(End) Ana Fiallos [CDS] 19-Jul-2023