J/A+A/621/A110 Two new giant planets around metal-poor stars (Barbato+, 2019)
The GAPS Programme with HARPS-N at TNG.
XVIII. Two new giant planets around the metal-poor stars HD 220197 and
HD 233832.
Barbato D., Sozzetti A., Biazzo K., Malavolta L., Santos N.C., Damasso M.,
Lanza A.F., Pinamonti M., Affer L., Benatti S., Bignamini A., Bonomo A.S.,
Borsa F., Carleo I., Claudi R., Cosentino R., Covino E., Desidera S.,
Esposito M., Giacobbe P., Gonzalez-Alvarez E., Gratton R., Harutyunyan A.,
Leto G., Maggio A., Maldonado J., Mancini L., Masiero S., Micela G.,
Molinari E., Nascimbeni V., Pagano I., Piotto G., Poretti E., Rainer M.,
Scandariato G., Smareglia R., Colombo L.S., Di Fabrizio L., Faria J.P.,
Martinez Fiorenzano A., Molinaro M., Pedani M.
<Astron. Astrophys. 621, A110 (2019)>
=2019A&A...621A.110B 2019A&A...621A.110B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, giant ; Radial velocities
Keywords: techniques: radial velocities - methods: data analysis -
planetary systems - stars: abundances -
stars: individual: HD 220197 - stars: individual: HD 233832
Abstract:
Statistical studies of exoplanets have shown that giant planets are
more commonly hosted by metal-rich dwarf stars than low-metallicity
stars, while no such correlation is evident for lower mass planets.
The search for giant planets around metal-poor stars and the estimate
of their occurrence fp is an important element in providing support
to models of planet formation.
We present results from the HARPS-N search for giant planets orbiting
metal-poor (-1.0≤[Fe/H]≤-0.5dex) stars in the northern hemisphere,
complementing a previous HARPS survey on southern stars in order to
update the estimate of fp.
High-precision HARPS-N observations of 42 metal-poor stars were used
to search for planetary signals to be fitted using differential
evolution Markov chain Monte Carlo single-Keplerian models. We then
joined our detections to the results of the previous HARPS survey on
88 metal-poor stars to provide a preliminary estimate of the
two-hemisphere fp.
We report the detection of two new giant planets around HD 220197 and
HD 233832. The first companion has Msini=0.20-0.04+0.07MJup and an
orbital period of 1728-80+162days, and for the second companion,
we find two solutions of equal statistical weight with periods of
2058-40+47 and 4047-117+91days and minimum masses of
1.78-0.06+0.08 and 2.72-0.23+0.23MJup, respectively. Joining
our two detections with the three from the southern survey, we obtain
a preliminary and conservative estimate of the global frequency
of fp=3.84-1.06+2.45% for giant planets around metal-poor stars.
The two new giant planets orbit dwarf stars at the metal-rich end of
the HARPS-N metal-poor sample. This corroborates previous results that
suggested that giant planet frequency is still a rising function of
the host star [Fe/H]. We also note that all detections in the overall
sample are giant long-period planets.
Description:
We carried out high-precision HARPS-N observations of two metal-poor
stars and report the discovery of two long-period giant planets. For
each of the target stars and each datapoint epoch of observation,
exposure time, radial velocity measurement, RV error, bisector,
full-width at half-maximum, logRHK and air mass are given.
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
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23 21 58.29 +16 37 57.1 HD 220197 = HIP 115359
11 26 05.48 +50 22 32.8 HD 233832 = HIP 55806
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 93 168 HARPS-N radial velocity measurements and
exposure times, activity indexes and airmass
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 9 A9 ---- Star Host star name (HD 220197 or HD 233832)
13- 26 F14.6 d BJD Epochs of radial velocities
30- 33 I4 s Texp Exposure time
36- 43 F8.4 km/s RV Radial velocity
47- 52 F6.4 km/s e_RV Radial velocity uncertainty
56- 61 F6.3 km/s BIS Bisector inverse span
65- 69 F5.3 km/s FWHM CCF full-width at half-maximum
73- 77 F5.3 km/s FWHMcorr ? CCF full-width at half-maximum (corrected)
81- 86 F6.3 ---- logRHK Activity index logRHK
90- 93 F4.2 ---- AirMass Air mass at exposure start
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Acknowledgements:
Domenico Barbato, domenico.barbato(at)inaf.it
(End) Patricia Vannier [CDS] 20-Nov-2018