J/AJ/163/159 Species abundances in WASP-77A (Reggiani+, 2022)
Evidence that the Hot Jupiter WASP-77Ab Formed Beyond Its Parent
Protoplanetary Disk's H2O Ice Line.
Reggiani H., Schlaufman K.C., Healy B.F., Lothringer J.D., Sing D.K.
<Astron. J., 163, 159 (2022)>
=2022AJ....163..159R 2022AJ....163..159R
ADC_Keywords: Exoplanets; Stars, high-velocity; Spectra, optical;
Spectra, infrared; Abundances
Keywords: Exoplanet astronomy ; Exoplanet formation ; Exoplanet migration
; Exoplanet systems ; Exoplanet atmospheric composition ;
Exoplanet tides ; Hot Jupiters ; Planet hosting stars ; Star-
planet interactions ; Stellar abundances
Abstract:
Idealized protoplanetary disk and giant planet formation models have
been interpreted to suggest that a giant planet's atmospheric
abundances can be used to infer its formation location in its parent
protoplanetary disk. It has recently been reported that the hot
Jupiter WASP-77Ab has subsolar atmospheric carbon and oxygen
abundances with a solar C/O abundance ratio. Assuming solar carbon and
oxygen abundances for its host star WASP-77A, WASP-77Ab's atmospheric
carbon and oxygen abundances possibly indicate that it accreted its
envelope interior to its parent protoplanetary disk's H2O ice line
from carbon-depleted gas with little subsequent planetesimal accretion
or core erosion. We show that the photospheric abundances of carbon
and oxygen in WASP-77A are supersolar with a subsolar C/O abundance
ratio, implying that WASP-77Ab's atmosphere has significantly
substellar carbon and oxygen abundances with a superstellar C/O ratio.
Our result possibly indicates that WASP-77Ab's envelope was accreted
by the planet beyond its parent protoplanetary disk's H2O ice line.
While numerous theoretical complications to these idealized models
have now been identified, the possibility of nonsolar protoplanetary
disk abundance ratios confound even the most sophisticated
protoplanetary disk and giant planet formation models. We therefore
argue that giant planet atmospheric abundance ratios can only be
meaningfully interpreted relative to the possibly nonsolar mean
compositions of their parent protoplanetary disks as recorded in the
photospheric abundances of their dwarf host stars.
Description:
We observed WASP-77A from Apache Point Observatory with the
Astrophysical Research Consortium (ARC) 3.5m Telescope and its ARC
Echelle Spectrograph (ARCES) for 750s starting at UTC 2021 February 23
01:42:55. We used the standard 1.6"x3.2" slit, yielding a spectrum
between 320 and 1000nm with spectral resolution R∼31500.
Objects:
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RA (2000) DE Designation(s)
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02 28 37.23 -07 03 38.4 WASP-77A = BD-07 436A
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 39 210 Atomic data, equivalent-width measurements, and
individual-line abundance inferences
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See also:
J/A+A/636/A98 : WASP-18A, WASP-19, WASP-77A photometry (Cortes-Zuleta+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 --- Wave [4445/9063] Wavelength; Angstroms
10- 13 A4 --- Species Species identifier
15- 19 F5.3 eV ExPot [0/9.15] Excitation potential
21- 26 F6.3 [-] logg [-6.13/0.43] log oscillator strength
28- 33 F6.2 --- EW [9.4/176]? Equivalent width; milli-Angstroms
35- 39 F5.3 [-] logX [2/9.06] log abundance
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 25-Apr-2022