J/A+A/583/A135 XO-2N and XO-2S spectra (Biazzo+, 2015)
The GAPS programme with HARPS-N at TNG.
X. Differential abundances in the XO-2 planet hosting binary.
Biazzo K., Gratton R., Desidera S., Lucatello S., Sozzetti A., Bonomo A.S.,
Damasso M., Gandolfi D., Affer L., Boccato C., Borsa F., Claudi R.,
Cosentino R., Covino E., Knapic C., Lanza A.F., Maldonado J., Marzari F.,
Micela G., Molaro P., Pagano I., Pedani M., Pillitteri I., Piotto G.,
Poretti E., Rainer M., Santos N.C., Scandariato G., Zanmar Sanchez R.
<Astron. Astrophys. 583, A135 (2015)>
=2015A&A...583A.135B 2015A&A...583A.135B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Spectroscopy
Keywords: planetary systems - stars: abundances - techniques: spectroscopic -
stars: individual: XO-2N - stars: individual: XO-2S
Abstract:
Binary stars hosting exoplanets are a unique laboratory where chemical
tagging can be performed to measure with high accuracy the elemental
abundances of both stellar components, with the aim to investigate the
formation of planets and their subsequent evolution. Here, we present
a high-precision differential abundance analysis of the XO-2 wide
stellar binary based on high resolution HARPS-N@TNG spectra. Both
components are very similar K-dwarfs and host planets. Since they
formed presumably within the same molecular cloud, we expect they
should possess the same initial elemental abundances. We investigate
if the presence of planets can cause some chemical imprints in the
stellar atmospheric abundances. We measure abundances of 25 elements
for both stars with a range of condensation temperature TC=40-1741K,
achieving typical precisions of ∼0.07dex. The North component
shows abundances in all elements higher by +0.067±0.032dex on
average, with a mean difference of +0.078dex for elements with
TC>800K. The significance of the XO-2N abundance difference relative
to XO-2S is at the 2σ level for almost all elements. We discuss
the possibility that this result could be interpreted as the signature
of the ingestion of material by XO-2N or depletion in XO-2S due to
locking of heavy elements by the planetary companions. We estimate a
mass of several tens of M{earth} in heavy elements. The difference
in abundances between XO-2N and XO-2S shows a positive correlation
with the condensation temperatures of the elements, with a slope of
(4.7±0.9)x10-5dex/K, which could mean that both components have
not formed terrestrial planets, but that first experienced the
accretion of rocky core interior to the subsequent giant planets.
Description:
Final reduced spectra used for the elemental abundance measurements.
We observed both XO-2 components with the high resolution HARPS-N@TNG
(R∼115000, λ∼3900-6900Å) spectrograph between November 20,
2012 and October 4, 2014. Solar spectra were also obtained through
observations of the asteroid Vesta. The spectra reduction was
obtained using the 2013 November version of the HARPS-N instrument
data reduction software (DRS) pipeline. A detailed description of the
observations and data reduction is reported in Paper II (Desidera et
al., 2013A&A...554A..29D 2013A&A...554A..29D)
Objects:
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RA (2000) DE Designation(s)
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07 48 06.47 +50 13 33.0 XO-2N = TYC 3413-5-1
07 48 07.48 +50 13 03.3 XO-2S = TYC 3413-210-1
--------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 89 2 List of spectra
fits/* . 2 Individual fits spectra
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See also:
J/ApJ/770/36 : APOSTLE transits of XO-2 system (Kundurthy+, 2013)
J/A+A/554/A28 : Qatar-1 differential light curve (Covino+, 2013)
J/A+A/575/A111 : GAPS V: Global analysis of the XO-2 system (Damasso+, 2015)
J/A+A/575/L15 : TrES-4b RV and Ic curves (Sozzetti+, 2015)
J/A+A/578/A64 : tau Bootis A radial velocity curve (Borsa+, 2015)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 23 F4.1 arcsec DEs Declination (J2000)
25- 30 I6 ---- Nx Number of points
32- 35 I4 0.1nm blambda Lower value of wavelength interval
37- 40 I4 0.1nm Blambda Upper value of wavelength interval
42- 45 F4.2 0.1nm dlambda Spectral resolution
47- 50 I4 Kibyte size Size of the fits file
52- 74 A23 --- FileName Name of the fits file in subdirectory fits
76- 89 A14 --- Title Title of the file
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Acknowledgements:
Katia Biazzo, katia.biazzo(at)oact.inaf.it
References:
Covino et al., Paper I 2013A&A...554A..28C 2013A&A...554A..28C, Cat. J/A+A/554/A28
Desidera et al., Paper II 2013A&A...554A..29D 2013A&A...554A..29D
Esposito et al., Paper III 2014A&A...564L..13E 2014A&A...564L..13E
Desidera et al. Paper IV 2014A&A...567L...6D 2014A&A...567L...6D
Damasso et al., Paper V 2015A&A...575A.111D 2015A&A...575A.111D, Cat. J/A+A/575/A111
Sozzetti et al., Paper VI 2015A&A...575L..15S 2015A&A...575L..15S, Cat. J/A+A/575/L15
Borsa et al., Paper VII 2015A&A...578A..64B 2015A&A...578A..64B, Cat. J/A+A/578/A64
Mancini et al., Paper VIII 2015A&A...579A.136M 2015A&A...579A.136M
(End) Patricia Vannier [CDS] 14-Sep-2015