2018A&A...612A..46M


Query : 2018A&A...612A..46M

2018A&A...612A..46M - Astronomy and Astrophysics, volume 612A, 46-46 (2018/4-1)

PEPSI deep spectra. III. Chemical analysis of the ancient planet-host star Kepler-444.

MACK C.E., STRASSMEIER K.G., ILYIN I., SCHULER S.C., SPADA F. and BARNES S.A.

Abstract (from CDS):


Context. With the Large Binocular Telescope (LBT), we obtained a spectrum with PEPSI, its new optical high-resolution echelle spectrograph. The spectrum has very high resolution and a high signal-to-noise (S/N) and is of the K0V host Kepler-444, which is known to host five sub-Earth-sized rocky planets. The spectrum has a resolution of R~=250000, a continuous wavelength coverage from 4230Å to 9120Å, and an S/N between 150-550:1 (blue to red).
Aims. We performed a detailed chemical analysis to determine the photospheric abundances of 18 chemical elements. These were used to place constraints on the bulk composition of the five rocky planets.
Methods. Our spectral analysis employs the equivalent-width method for most of our spectral lines, but we used spectral synthesis to fit a small number of lines that required special care. In both cases, we derived our abundances using the MOOG spectral analysis package and Kurucz model atmospheres.
Results. We find no correlation between elemental abundance and condensation temperature among the refractory elements (TC>950K). In addition, using our spectroscopic stellar parameters and isochrone fitting, we find an age of 10±1.5Gyr, which is consistent with the asteroseismic age of 11±1Gyr. Finally, from the photospheric abundances of Mg, Si, and Fe, we estimate that the typical Fe-core mass fraction for the rocky planets in the Kepler-444 system is approximately 24%.
Conclusions. If our estimate of the Fe-core mass fraction is confirmed by more detailed modeling of the disk chemistry and simulations of planet formation and evolution in the Kepler-444 system, then this would suggest that rocky planets in more metal-poor and α-enhanced systems may tend to be less dense than their counterparts of comparable size in more metal-rich systems.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: abundances - stars: atmospheres - stars: late-type - stars: activity - planetary systems

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NGC 1039 OpC 02 42 07 +42 43.3           ~ 402 0
2 HD 20782 PM* 03 20 03.5777546706 -28 51 14.660358176   8.03 7.38     G1.5V 187 1
3 Cl Melotte 22 OpC 03 46 24 +24 06.8           ~ 3260 0
4 Cl Melotte 25 OpC 04 29 47 +16 56.9           ~ 2910 0
5 CoRoT-7b Pl 06 43 49.4690410679 -01 03 46.825797768           ~ 382 1
6 NGC 2682 OpC 08 51 23 +11 48.8           ~ 2218 0
7 HD 80606 PM* 09 22 37.5768032712 +50 36 13.435326684   9.78 9.00     G8V 310 2
8 NAME Ursa Major Moving Group MGr 12 32 +57.0           ~ 417 2
9 BD+44 3020 PM* 18 56 14.3076037320 +44 31 05.389610412   10.45 9.77     G8V 110 1
10 Kepler-10b Pl 19 02 43.0613892904 +50 14 28.701617339           ~ 277 1
11 BD+41 3306 PM* 19 19 00.5489000285 +41 38 04.582441681 10.01 9.67 8.86 8.18 7.66 K0V 257 0
12 BD+38 3583b Pl 19 25 40.3886092719 +38 40 20.411344230           ~ 94 0
13 NGC 6819 OpC 19 41 18 +40 11.4   8.21 7.3     ~ 561 0

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2022.12.02-15:38:32

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