J/AJ/160/201 Infrared transmission spectrum for Kepler-79d (Chachan+, 2020)
A Featureless infrared transmission spectrum for the super-puff planet
Kepler-79d.
Chachan Y., Jontof-Hutter D., Knutson H.A., Adams D., Gao P., Benneke B.,
Berta-Thompson Z., Dai F., Deming D., Ford E.B., Lee E.J.,
Libby-Roberts J.E., Madhusudhan N., Wakeford H.R., Wong I.
<Astron. J., 160, 201 (2020)>
=2020AJ....160..201C 2020AJ....160..201C
ADC_Keywords: Exoplanets; Stars, variable; Spectra, infrared
Keywords: Exoplanet atmospheres ; Exoplanet evolution ; Exoplanets
Abstract:
Extremely low-density planets ("super-puffs") are a small but
intriguing subset of the transiting planet population. With masses in
the super-Earth range (1-10M⊕) and radii akin to those of giant
planets (>4R⊕), their large envelopes may have been accreted
beyond the water snow line and many appear to be susceptible to
catastrophic mass loss. Both the presence of water and the importance
of mass loss can be explored using transmission spectroscopy. Here, we
present new Hubble space telescope WFC3 spectroscopy and updated
Kepler transit depth measurements for the super-puff Kepler-79d. We do
not detect any molecular absorption features in the 1.1-1.7µm WFC3
bandpass, and the combined Kepler and WFC3 data are consistent with a
flat-line model, indicating the presence of aerosols in the
atmosphere. We compare the shape of Kepler-79d transmission spectrum
to predictions from a microphysical haze model that incorporates an
outward particle flux due to ongoing mass loss. We find that
photochemical hazes offer an attractive explanation for the observed
properties of super-puffs like Kepler-79d, as they simultaneously
render the near-infrared spectrum featureless and reduce the inferred
envelope mass-loss rate by moving the measured radius (optical depth
unity surface during transit) to lower pressures. We revisit the
broader question of mass-loss rates for super-puffs and find that the
age estimates and mass-loss rates for the majority of super-puffs can
be reconciled if hazes move the photosphere from the typically assumed
pressure of ∼10mbar to ∼10µbar.
Description:
We observed transits of Kepler-79d with Hubble Space Telescope (HST)
Wide Field Camera 3 (WFC3) instrument on UT 2018 April 12 and UT 2018
November 6 (PI: Jontof-Hutter, GO: 15138).
Objects:
----------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
----------------------------------------------------------------
20 02 04.11 +44 22 53.6 Kepler-79d = Kepler-79d (P=52.0897d)
----------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 42 18 Spectroscopic light curve fit results
table6.dat 104 23 Planet properties
fig4.dat 240 10000 Transit Time Variations (TTV) posterior samples
--------------------------------------------------------------------------------
See also:
VI/39 : Model Atmospheres (Kurucz, 1979)
J/ApJ/723/L223 : Radial velocities of HAT-P-11 (Winn+, 2010)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/ApJ/747/35 : HST/WFC3 transit observation of GJ1214b (Berta+, 2012)
J/ApJ/790/146 : Planets Kepler's multi-transiting systems (Fabrycky+, 2014)
J/ApJ/785/15 : Transit times for Kepler-79's planets (Jontof-Hutter+, 2014)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/ApJS/210/25 : Transit timing variation for 15 planetary pairs. II. (Xie,2014)
J/ApJ/806/183 : Planet radii of Kepler Object of Interest (Wolfgang+, 2015)
J/A+A/586/A75 : Simulations of hot gas planets atmospheres (Salz+, 2016)
J/MNRAS/466/1868 : Neptune-like planets low-density overabund. (Cubillos+ 2017)
J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)
J/AJ/154/5 : Transit timing variations of 145 Kepler planets (Hadden+, 2017)
J/AJ/154/107 : California-Kepler Survey (CKS). I. 1305 stars (Petigura+, 2017)
J/AJ/156/264 : California-Kepler Survey. VII. Planet radius gap (Fulton+,2018)
J/AJ/158/244 : HAT-P-11b spectroscopic light curve fit results (Chachan+,2019)
J/AJ/157/174 : Transiting planets Kepler-47 circumbinary system (Orosz+, 2019)
J/ApJ/874/L31 : Giant planet bulk & atmosphere metallicities (Thorngren+, 2019)
J/AJ/159/57 : HST spectroscopic LCs of Kepler 51b & 51d (Libby-Roberts+,2020)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.3 um Wavemin [1.12/1.63] Lower wavelength edge of Bandpass
7- 11 F5.3 um Wavemax [1.15/1.66] Upper wavelength edge of Bandpass
13- 17 F5.3 um Wave [1.13/1.65] Mean wavelength edge of Bandpass
19- 25 F7.5 --- RpR [0.04/0.06] Ratio of the planet's and star's radii
27- 33 F7.5 --- e_RpR [0.001/0.002] The 1σ uncertainty in Rp/R*
35- 38 I4 ppm Depth [2057/2719] Transit depth of the planet
40- 42 I3 ppm e_Depth [101/161] 1σ uncertainty in transit depth
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Planet Planet identification
14- 14 A1 --- r_Planet Planetary data reference flag (1)
16- 19 F4.1 Mgeo Mass [1.9/62.1] Planet mass
21- 24 F4.1 Mgeo E_Mass [0.3/10.2] 1σ upper uncertainty in Mass
26- 29 F4.1 Mgeo e_Mass [0.2/10.9] 1σ lower uncertainty in Mass
31- 34 F4.1 Rgeo Rad [2.8/10.1] Planet radius
36- 38 F3.1 Rgeo e_Rad [0.1/2.8] The 1σ uncertainty in Rad
40- 43 F4.2 g/cm3 rho [0.03/0.95] Planet density
45- 48 F4.2 g/cm3 E_rho [0.01/0.69] 1σ upper uncertainty in rho
50- 53 F4.2 g/cm3 e_rho [0.01/0.48] 1σ lower uncertainty in rho
55- 60 F6.4 au a [0.0752/0.4907] Planet semi-major axis
62- 67 F6.4 au e_a [0.0008/0.004] The 1σ uncertainty in a
69- 73 F5.1 Earth Sinc [2.6/414.4] Incident stellar flux
75- 78 F4.1 Earth e_Sinc [0.2/57.1] The 1σ uncertainty in Sinc
80- 83 F4.1 [Gyr] [Age] [0.5/11.7] log, Planet age
85- 87 F3.1 [Gyr] E_[Age] [0.2/4.2] 1σ upper uncertainty in [Age]
89- 91 F3.1 [Gyr] e_[Age] [0.2/4.0] 1σ lower uncertainty in [Age]
93- 96 F4.1 [Gyr] [lifeTime] [-2.6/3.4] log, planet atmospheric lifetime
98-100 F3.1 [Gyr] E_[lifeTime] [0.1/7.2] 1σ upper uncertainty in
[lifeTime]
102-104 F3.1 [Gyr] e_[lifeTime] [0.1/4.9] 1σ lower uncertainty in
[lifeTime]
--------------------------------------------------------------------------------
Note (1): References as follows :
a = (18 occurrences) Mass ratio posteriors from
Hadden & Lithwick, 2017, J/AJ/154/5. Stellar masses, planetary radii,
semi-major axes, incident stellar fluxes, and ages from
Fulton & Petigura, 2018, J/AJ/156/264.
b = (3 occurrences) Mass ratio posteriors, planetary radii, and stellar age
from Libby-Roberts+, 2020, J/AJ/159/57. Stellar mass, semi-major axes,
and incident stellar fluxes from Fulton & Petigura, 2018, J/AJ/156/264.
c = (2 occurrences) Mass ratio posteriors and planetary radii from this
study. Stellar masses, semi-major axes, incident stellar fluxes, and
ages from Fulton & Petigura, 2018, J/AJ/156/264.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: fig4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.8 Mgeo Massb Planet mass for stellar mass=1 Msun, Kepler-79b (1)
13- 23 F11.8 d Perb Orbital period, Kepler-79b
25- 35 F11.8 --- esinwb Eccentricity vector sinus component, Kepler-79b
37- 47 F11.8 --- ecoswb Eccentricity vector cosinus component, Kepler-79b
49- 60 F12.8 d T0b First transit after epoch, Kepler-79b (2)
62- 71 F10.8 Mgeo Massc Planet mass for stellar mass=1 Msun, Kepler-79c (1)
73- 83 F11.8 d Perc Orbital period, Kepler-79c
85- 95 F11.8 --- esinwc Eccentricity vector sinus component, Kepler-79c
97-107 F11.8 --- ecoswc Eccentricity vector cosinus component, Kepler-79c
109-120 F12.8 d T0c First transit after epoch, Kepler-79c (2)
122-131 F10.8 Mgeo Massd Planet mass for stellar mass=1 Msun, Kepler-79d (1)
133-143 F11.8 d Perd Orbital period, Kepler-79d
145-155 F11.8 --- esinwd Eccentricity vector sinus component, Kepler-79d
157-167 F11.8 --- ecoswd Eccentricity vector cosinus component, Kepler-79d
169-180 F12.8 d T0d First transit after epoch, Kepler-79d (2)
182-191 F10.8 Mgeo Masse Planet mass for stellar mass=1 Msun, Kepler-79e (1)
193-203 F11.8 d Pere Orbital period, Kepler-79e
205-215 F11.8 --- esinwe Eccentricity vector sinus component, Kepler-79e
217-227 F11.8 --- ecoswe Eccentricity vector cosinus component, Kepler-79e
229-240 F12.8 d T0e First transit after epoch, Kepler-79e (2)
--------------------------------------------------------------------------------
Note (1): Planet mass in units of (Mp/Mstar)*(Msun/Mearth). Multiply by
Kepler-79's mass (in units of solar mass) to obtain true planet mass
in Earth masses.
Note (2): Epoch = 780.0 and t0 corresponds to BJD-2454900.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 13-Jan-2021