J/A+A/673/A98 51 Eri b SPHERE/IFS YH spectrum (Brown-Sevilla+, 2023)
Revisiting the atmosphere of the exoplanet 51 Eridani b with VLT/SPHERE.
Brown-Sevilla S.B., Maire A.-L., Molliere P., Samland M., Feldt M.,
Brandner W., Henning T., Gratton R., Janson M., Stolker T., Hagelberg J.,
Zurlo A., Cantalloube F., Boccaletti A., Bonnefoy M., Chauvin G.,
Desidera S., D'Orazi V., Lagrange A.-M., Langlois M., Menard F., Mesa D.,
Meyer M., Pavlov A., Petit C., Rochat S., Rouan D., Schmidt T., Vigan A.,
Weber L.
<Astron. Astrophys. 673, A98 (2023)>
=2023A&A...673A..98B 2023A&A...673A..98B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Spectroscopy ;
Spectra, infrared ; Models, atmosphere
Keywords: stars: individual: 51 Eridani - planets and satellites: atmospheres -
techniques: image processing
Abstract:
51 Eridani b is one of the closest directly imaged exoplanets (∼11au).
We aim to better constrain its atmospheric properties by using a
retrieval approach on higher signal-to-noise ratio data than
previously reported. We present a higher signal-to-noise ratio YH
spectrum of the planet and revised K1K2 photometry
(MK1=15.11±0.04mag, MK2=17.11±0.38mag). We compare the results
of using the atmospheric retrieval code petitRADTRANS to a
self-consistent model to fit our near-infrared SPHERE observations.
Additionally, we attempt to reproduce previous results with the
retrieval approach and compare the results to self-consistent models
using the best-fit parameters from the retrieval as priors. The
best-fit parameters obtained using an atmospheric retrieval differ
from previous results using self-consistent models. In general, we
find that our solutions tend towards cloud-free atmospheres (e.g.
logtauclouds≃5.20±1.44). For our 'nominal' model with new data,
we find a lower metallicity ([Fe/H]=0.26±0.30dex) and C/O ratio
(0.38±0.09), and a slightly higher effective temperature
(Teff=807±45K) than previous studies. The surface gravity
(logg=4.05±0.37) is in agreement with the reported values in the
literature within uncertainties. We estimate the mass of the planet to
be between 2 and 4MJup. When comparing with self-consistent models,
we encounter a known correlation between the presence of clouds and
the shape of the P-T profiles. Our findings support the idea that
results from atmospheric retrievals should not be discussed in
isolation, but rather along with self-consistent temperature
structures obtained using the retrieval's best-fit parameters. This,
along with observations at longer wavelengths, might help to better
characterise the atmospheres and determine their degree of cloudiness.
Description:
SPHERE IFS-YH spectrum of 51 Eridani b in Fig. 2, and the
corresponding correlation matrix for the uncertainty of the spectral
points in Fig. C1.
Objects:
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RA (2000) DE Designation(s)
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04 37 36.13 -02 28 24.8 51 Eri = HR 1474
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectrum.dat 74 39 Near-infrared (YH) spectrum of 51 Eri b
correl.dat 1013 39 Correlation matrix for the YH spectrum
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See also:
J/A+A/603/A57 : 51 Eri b SPHERE/IFS spectra + atmosphere models (Samland+ 2017)
Byte-by-byte Description of file: spectrum.dat
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Bytes Format Units Label Explanations
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1- 24 E24.18 um lambda Wavelength
26- 49 E24.18 W/m2/um Flux Flux (flambda)
51- 74 E24.18 W/m2/um e_Flux Flux uncertainty
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Byte-by-byte Description of file: correl.dat
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Bytes Format Units Label Explanations
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1- 25 E25.19 --- C1 Correlation coefficient for i=1
27- 51 E25.19 --- C2 Correlation coefficient for i=2
53- 77 E25.19 --- C3 Correlation coefficient for i=3
79- 103 E25.19 --- C4 Correlation coefficient for i=4
105- 129 E25.19 --- C5 Correlation coefficient for i=5
131- 155 E25.19 --- C6 Correlation coefficient for i=6
157- 181 E25.19 --- C7 Correlation coefficient for i=7
183- 207 E25.19 --- C8 Correlation coefficient for i=8
209- 233 E25.19 --- C9 Correlation coefficient for i=9
235- 259 E25.19 --- C10 Correlation coefficient for i=10
261- 285 E25.19 --- C11 Correlation coefficient for i=11
287- 311 E25.19 --- C12 Correlation coefficient for i=12
313- 337 E25.19 --- C13 Correlation coefficient for i=13
339- 363 E25.19 --- C14 Correlation coefficient for i=14
365- 389 E25.19 --- C15 Correlation coefficient for i=15
391- 415 E25.19 --- C16 Correlation coefficient for i=16
417- 441 E25.19 --- C17 Correlation coefficient for i=17
443- 467 E25.19 --- C18 Correlation coefficient for i=18
469- 493 E25.19 --- C19 Correlation coefficient for i=19
495- 519 E25.19 --- C20 Correlation coefficient for i=20
521- 545 E25.19 --- C21 Correlation coefficient for i=21
547- 571 E25.19 --- C22 Correlation coefficient for i=22
573- 597 E25.19 --- C23 Correlation coefficient for i=23
599- 623 E25.19 --- C24 Correlation coefficient for i=24
625- 649 E25.19 --- C25 Correlation coefficient for i=25
651- 675 E25.19 --- C26 Correlation coefficient for i=26
677- 701 E25.19 --- C27 Correlation coefficient for i=27
703- 727 E25.19 --- C28 Correlation coefficient for i=28
729- 753 E25.19 --- C29 Correlation coefficient for i=29
755- 779 E25.19 --- C30 Correlation coefficient for i=30
781- 805 E25.19 --- C31 Correlation coefficient for i=31
807- 831 E25.19 --- C32 Correlation coefficient for i=32
833- 857 E25.19 --- C33 Correlation coefficient for i=33
859- 883 E25.19 --- C34 Correlation coefficient for i=34
885- 909 E25.19 --- C35 Correlation coefficient for i=35
911- 935 E25.19 --- C36 Correlation coefficient for i=36
937- 961 E25.19 --- C37 Correlation coefficient for i=37
963- 987 E25.19 --- C38 Correlation coefficient for i=38
989-1013 E25.19 --- C39 Correlation coefficient for i=39
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Acknowledgements:
Samantha B. Brown-Sevilla, brown(at)mpia.de
(End) Patricia Vannier [CDS] 27-Jan-2023