J/ApJ/819/19 Equivalent widths of WASP-94A and WASP-94B (Teske+, 2016)
The curious case of elemental abundance differences in the dual hot
Jupiter hosts WASP-94A and B.
Teske J.K., Khanal S., Ramirez I.
<Astrophys. J., 819, 19 (2016)>
=2016ApJ...819...19T 2016ApJ...819...19T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Equivalent widths
Keywords: planets and satellites: formation;
planets and satellites: individual: WASP-94; stars: abundances;
stars: atmospheres
Abstract:
Binary stars provide an ideal laboratory for investigating the
potential effects of planet formation on stellar composition. Assuming
that the stars formed in the same environment/from the same material,
any compositional anomalies between binary components might indicate
differences in how material was sequestered in planets, or accreted by
the star in the process of planet formation. We present here a study
of the elemental abundance differences between WASP-94A and B, a pair
of stars that each host a hot Jupiter exoplanet. The two stars are
very similar in spectral type (F8 and F9), and their ∼2700AU
separation suggests that their protoplanetary disks were likely not
influenced by stellar interactions, but WASP-94Ab's orbit --misaligned
with the host star spin axis and likely retrograde-- points toward a
dynamically active formation mechanism, perhaps different from that of
WASP-94Bb, which is not misaligned and has a nearly circular orbit.
Based on our high-quality spectra and strictly relative abundance
analysis, we detect a depletion of volatiles (~-0.02dex, on average)
and enhancement of refractories (∼0.01dex) in WASP-94A relative to B
(standard errors are ∼0.005dex). This is different from every other
published case of binary host star abundances, in which either no
significant abundance differences are reported or there is some degree
of enhancement in all elements, including volatiles. Several scenarios
that may explain the abundance trend are discussed, but none can be
definitively accepted or rejected. Additional high-contrast imaging
observations to search for companions that may be dynamically
affecting the system, as well as a larger sample of binary host star
studies, are needed to better understand the curious abundance trends
we observe in WASP-94A and B.
Description:
Observations of WASP-94AB were acquired on 2015 May 1 (UT) with the
MIKE high-resolution spectrograph on the 6.5m Clay Magellan Telescope
at Las Campanas Observatory. The standard MIKE setup was used with a
0.5" slit, providing ∼320-1000nm wavelength coverage and R∼45000.
Objects:
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RA (ICRS) DE Designation(s)
---------------------------------------------------------
20 55 07.95 -34 08 08.0 WASP-94A = UCAC4 280-221528
20 55 09.16 -34 08 07.9 WASP-94B = UCAC4 280-221531
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 70 531 Measured lines and equivalent widths
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See also:
J/A+A/580/A24 : Abundances in dwarfs, subgiants, and giants (da Silva+, 2015)
J/A+A/576/A69 : Li abundances in F stars (Delgado+, 2015)
J/A+A/572/A49 : WASP-94AB photometry and RVs (Neveu-VanMalle+, 2014)
J/A+A/562/A71 : Solar neighbourhood dwarf chemical abundances (Bensby+, 2014)
J/A+A/561/A7 : Abundances for stars with planets (Ramirez+, 2014)
J/ApJ/771/107 : Spectroscopy of faint KOI stars (Everett+, 2013)
J/A+A/552/A6 : Abundances of F-G MS stars (Gonzalez Hernandez+, 2013)
J/ApJ/743/24 : Solar models with accretion. I. (Serenelli+, 2011)
J/ApJ/732/55 : Abundances of stars with planets (Schuler+, 2011)
J/ApJ/720/1290 : Abundances of stars hosting planets (Ghezzi+, 2010)
J/ApJ/715/1050 : Predicted abundances for extrasolar planets. I. (Bond+, 2010)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/A+A/508/L17 : Abundances in solar analogs (Ramirez+, 2009)
J/A+A/487/373 : Spectroscopic parameters of 451 HARPS-GTO stars (Sousa+, 2008)
J/A+A/465/271 : Oxygen abundances in nearby stars (Ramirez+, 2007)
J/A+A/454/581 : Iron abundances of 33 wide binaries (Desidera+, 2006)
J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)
J/A+A/420/683 : Equivalent widths of 23 wide binaries (Desidera+, 2004)
J/A+A/415/1153 : [Fe/H] for 98 extra-solar planet-host stars (Santos+, 2004)
J/A+A/377/123 : Equivalent widths of 6 binaries (Gratton+, 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Ion Ion
6- 13 F8.3 0.1nm lambda [4218.7/8435.7] Wavelength in Angstroms
15- 20 F6.4 eV ExPot [0/9.2] Excitation potential
22- 28 F7.4 [---] log(gf) [-5.5/0.6] Log of the oscillator strength
30- 34 F5.1 10-13m EWS [12.5/119.5]? Equivalent width of
the solar spectrum
36- 40 F5.1 10-13m EWA-IR [3.9/169]? Equivalent width of the
WASP-94A spectrum measured by Ramirez I.
42- 46 F5.1 10-13m EWA-SK [3.6/167]? Equivalent width of the
WASP-94A spectrum measured by Khanal S.
48- 52 F5.1 10-13m EWA-JT [3.6/166]? Equivalent width of the
WASP-94A spectrum measured by Teske J.K.
54- 58 F5.1 10-13m EWB-IR [4/173.3]? Equivalent width of the
WASP-94B spectrum measured by Ramirez I.
60- 64 F5.1 10-13m EWB-SK [4.9/167]? Equivalent width of the
WASP-94B spectrum measured by Khanal S.
66- 70 F5.1 10-13m EWB-JT [4.7/166]? Equivalent width of the
WASP-94B spectrum measured by Teske J.K.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 12-May-2016