J/AJ/164/143 Spectroscopy of HR 8799 planets with SCExAO/CHARIS (Wang+, 2022)
Atmospheric Monitoring and Precise Spectroscopy of the HR 8799 Planets with
SCExAO/CHARIS.
Wang J.J., Gao P., Chilcote J., Lozi J., Guyon O., Marois C., De Rosa R.J.,
Sahoo A., Groff T.D., Vievard S., Jovanovic N., Greenbaum A.Z., Macintosh B.
<Astron. J., 164, 143 (2022)>
=2022AJ....164..143W 2022AJ....164..143W
ADC_Keywords: Exoplanets; Stars, variable; Spectra, infrared;
Photometry, infrared
Keywords: Exoplanet atmospheres ; Exoplanet atmospheric variability ;
Coronagraphic imaging ; Spectrophotometry
Abstract:
The atmospheres of gas giant planets are thought to be inhomogeneous
due to weather and patchy clouds. We present two full nights of
coronagraphic observations of the HR8799 planets using the CHARIS
integral field spectrograph behind the SCExAO adaptive optics system
on the Subaru Telescope to search for spectrophotometric variability.
We did not detect significant variability signals, but placed the
lowest variability upper limits for HR 8799c and d. Based on
injection-recovery tests, we expected to have a 50% chance to detect
signals down to 10% H-band photometric variability for HR 8799c and
down to 30% H-band variability for HR8799d. We also investigated
spectral variability and expected a 50% chance to recover 20%
variability in the H/K flux ratio for HR8799c. We combined all the
data from the two nights to obtain some of the most precise spectra
obtained for HR8799c, d, and e. Using a grid of cloudy
radiative-convective-thermochemical equilibrium models, we found all
three planets prefer supersolar metallicity with effective
temperatures of ∼1100K. However, our high signal-to-noise spectra show
that HR8799d has a distinct spectrum from HR8799c, possibly preferring
more vertically extended and uniform clouds and indicating that the
planets are not identical.
Description:
HR8799 was observed at the Subaru telescope on two consecutive nights
for nearly the entire time using the Coronagraphic High Angular
Resolution Imaging Spectrograph (CHARIS) integral field spectrograph
behind the The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO)
high-order adaptive optics system with its Lyot coronagraph. We
obtained 20s exposures using the CHARIS low-resolution mode that
obtained R∼20 spectra from the J through K band. On 2018 September 1
(night 1), we obtained 1201 usable frames of data from 7:03 to 15:34
UT, resulting in a total on-sky integration time of 24805s. On 2018
September 2 (night 2), we obtained 1253 usable frames of data from
6:11 to 15:45 UT after discarding 89 frames with unusual detector
noise, resulting in a total on-sky integration time of 25879s.
Objects:
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RA (2000) DE Designation(s)
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23 07 28.72 +21 08 03.3 HR 8799 = HD 218396
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig2.dat 126 22 Spectra of HR 8799 c, d, and e resulting from
summing 8 hours of data from each night
fig5.dat 172 23 Time-series of the flux of HR 8799 c and d
integrated over J, H, F190, and K bands
fig8.dat 172 23 Time-series of the flux ratios between various bands
for HR 8799 c and d
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/587/A57 : HR 8799e and HR 8799d spectra (Zurlo+, 2016)
J/AJ/155/226 : Gemini Planet Imager spectra of HR8799 c/d/e (Greenbaum+, 2018)
J/AJ/162/290 : OSIRIS K-band spectra of planets HR8799 b, c, d (Ruffio+, 2021)
Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 5 F5.3 um Wave [1.16/2.37] Wavelength
7- 15 E9.3 W/m2/um c1Flux [3e-17/2e-16] HR8799c flux density on Night 1
17- 25 E9.3 W/m2/um e_c1Flux [1e-18/3e-17] Uncertainty in c1Flux
27- 35 E9.3 W/m2/um d1Flux [3e-17/2e-16] HR8799d flux density on Night 1
37- 45 E9.3 W/m2/um e_d1Flux [3e-18/3e-17] Uncertainty in d1Flux
47- 56 E10.3 W/m2/um e1Flux [-4e-17/2e-16] HR8799e flux density on Night 1
58- 66 E9.3 W/m2/um e_e1Flux [7e-18/8e-17] Uncertainty in e1Flux
68- 76 E9.3 W/m2/um c2Flux [4e-17/3e-16] HR8799c flux density on Night 2
78- 86 E9.3 W/m2/um e_c2Flux [2e-18/2e-17] Uncertainty in c2Flux
88- 96 E9.3 W/m2/um d2Flux [4e-17/2e-16] HR8799d flux density on Night 2
98-106 E9.3 W/m2/um e_d2Flux [3e-18/4e-17] Uncertainty in d2Flux
108-116 E9.3 W/m2/um e2Flux [2e-17/2e-16] HR8799e flux density on Night 2
118-126 E9.3 W/m2/um e_e2Flux [8e-18/1e-16] Uncertainty in e2Flux
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Byte-by-byte Description of file: fig5.dat
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Bytes Format Units Label Explanations
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1- 1 I1 h Bin [1/2] Bin duration
3- 11 F9.3 d MJD [58362/58364] Modified Julian Date;
MJD-2400000.5
13- 21 E9.3 W/m2/um cJphot [8e-17/2e-16] HR8799c J band flux in Bin
23- 31 E9.3 W/m2/um e_cJphot [3e-18/5e-17] Uncertainty in cJphot
33- 41 E9.3 W/m2/um cHphot [1e-16/2e-16] HR8799c H band flux in Bin
43- 51 E9.3 W/m2/um e_cHphot [2e-18/2e-17] Uncertainty in cHphot
53- 61 E9.3 W/m2/um cKphot [1e-16/2e-16] HR8799c K band flux in Bin
63- 71 E9.3 W/m2/um e_cKphot [1e-18/2e-16] Uncertainty in cKphot
73- 81 E9.3 W/m2/um c190phot [6e-17/2e-16] HR8799c F190 band flux in Bin
83- 91 E9.3 W/m2/um e_c190phot [1e-18/2e-17] Uncertainty in c190phot
93-102 E10.3 W/m2/um dJphot [-2e-17/2e-16] HR8799d J band flux in Bin
104-112 E9.3 W/m2/um e_dJphot [3e-18/1e-16] Uncertainty in dJphot
114-122 E9.3 W/m2/um dHphot [1e-16/2e-16] HR8799d H band flux in Bin
124-132 E9.3 W/m2/um e_dHphot [2e-18/4e-17] Uncertainty in dHphot
134-142 E9.3 W/m2/um dKphot [1e-16/2e-16] HR8799d K band flux in Bin
144-152 E9.3 W/m2/um e_dKphot [2e-18/2e-17] Uncertainty in dKphot
154-162 E9.3 W/m2/um d190phot [7e-17/2e-16] HR8799d F190 band flux in Bin
164-172 E9.3 W/m2/um e_d190phot [2e-18/3e-17] Uncertainty in d190phot
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Byte-by-byte Description of file: fig8.dat
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Bytes Format Units Label Explanations
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1- 1 I1 h Bin [1/2] Bin duration
3- 11 F9.3 d MJD [58362/58364] Modified Julian Date;
MJD-2400000.5
13- 21 E9.3 --- cJKRatio [0.58/1] HR8799c J/K bands flux ratio in Bin
23- 31 E9.3 --- e_cJKRatio [0.03/0.4] Uncertainty in cJ/KRatio
33- 41 E9.3 --- cHKRatio [0.87/1.25] HR8799c H/K bands flux ratio in
Bin
43- 51 E9.3 --- e_cHKRatio [0.02/0.1] Uncertainty in cH/KRatio
53- 61 E9.3 --- cH190Ratio [1.55/2.15] HR8799c H/F190 bands flux ratio
in Bin
63- 71 E9.3 --- e_cH190Ratio [0.04/0.3] Uncertainty in cH/190Ratio
73- 81 E9.3 --- cK190Ratio [1.54/1.92] HR8799c K/F190 bands flux ratio
in Bin
83- 91 E9.3 --- e_cK190Ratio [0.03/0.4] Uncertainty in cK/190Ratio
93-102 E10.3 --- dJKRatio [-0.08/1.14] HR8799d J/K bands flux ratio
in Bin
104-112 E9.3 --- e_dJKRatio [0.02/0.7] Uncertainty in dJ/KRatio
114-122 E9.3 --- dHKRatio [0.87/1.31] HR8799d H/K bands flux ratio
in Bin
124-132 E9.3 --- e_dHKRatio [0.03/0.4] Uncertainty in dH/KRatio
134-142 E9.3 --- dH190Ratio [1.37/1.79] HR8799d H/F190 bands flux ratio
in Bin
144-152 E9.3 --- e_dH190Ratio [0.06/0.6] Uncertainty in dH/190Ratio
154-162 E9.3 --- dK190Ratio [1.09/1.69] HR8799d K/F190 bands flux ratio
in Bin
164-172 E9.3 --- e_dK190Ratio [0.04/0.4] Uncertainty in dK/190Ratio
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 22-Nov-2022