J/A+A/643/A106 55 close-in (P<100days) small planets list (Bashi+, 2020)
Occurrence rates of small planets from HARPS. Focus on the Galactic context.
Bashi D., Zucker S., Adibekyan V., Santos N.C., Tal-or L., Trifonov T.,
Mazeh T.
<Astron. Astrophys., 643, A106 (2020)>
=2020A&A...643A.106B 2020A&A...643A.106B (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, double and multiple ; Exoplanets
Keywords: planets and satellites: general - Galaxy: disk - stars: abundances -
stars: statistics - stars: solar-type - methods: statistical
Abstract:
The stars in the Milky Way thin and thick disks can be distinguished
by several properties such as metallicity and kinematics. It is not
clear whether the two populations also differ in the properties of
planets orbiting the stars. In order to study this, a careful analysis
of both the chemical composition and mass detection limits is required
for a sufficiently large sample. Currently, this information is still
limited only to large radial-velocity (RV) programs. Based on the
recently published archival database of the High Accuracy Radial
velocity Planet Searcher (HARPS) spectrograph, we present a first
analysis of low-mass (small) planet occurrence rates in a sample of
thin- and thick-disk stars.
We aim to assess the effects of stellar properties on planet
occurrence rates and to obtain first estimates of planet occurrence
rates in the thin and thick disks of the Galaxy. As a baseline for
comparison, we also aim to provide an updated value for the small
close-in planet occurrence rate and compare it with the results of
previous RV and transit (Kepler) works.
We used archival HARPS RV datasets to calculate detection limits of a
sample of stars that were previously analysed for their elemental
abundances. For stars with known planets we first subtracted the
Keplerian orbit. We then used this information to calculate planet
occurrence rates according to a simplified Bayesian model in different
regimes of stellar and planet properties.
Our results suggest that metal-poor stars and more massive
stars host fewer low-mass close-in planets. We find the occurrence
rates of these planets in the thin and thick disks to be comparable.
In the iron-poor regimes, we find these occurrence rates to be
significantly larger at the high-α region (thick-disk stars) as
compared with the low-α region (thin-disk stars). In general, we
find the average number of close-in small planets (2-100 days,
1-20M⊕) per star (FGK-dwarfs) to be: n-p=0.36±0.05,
while the fraction of stars with planets is Fh=0.23-0.03+0.04.
Qualitatively, our results agree well with previous estimates based on
RV and Kepler surveys.
This work provides a first estimate of the close-in small planet
occurrence rates in the solar neighbourhood of the thin and thick
disks of the Galaxy. It is unclear whether there are other stellar
properties related to the Galactic context that affect small-planet
occurrence rates, or if it is only the combined effects of stellar
metal content and mass. A future larger sample of stars and planets is
needed to address those questions.
Description:
We present a list of 55 close-in (P<100days) small planets
(Mpsini<30M⊕) orbiting 34 stars that were found to be above
the detection limit.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 53 55 Planet and host parameters for each of the
55 planets we identified
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Planet name
14- 18 F5.2 d Per Orbital period
20- 24 F5.2 Mgeo Mpsini Planet mass
26- 29 F4.2 Msun Mhost Host star mass
31- 35 F5.2 [-] [Fe/H] Metallicity (1)
37- 40 F4.2 --- [alpha/Fe] Abundance [alpha/Fe] (1)
42- 48 E7.3 --- PGal Galactic affiliation probability PGal (2)
50- 53 F4.2 --- PS PS planet detection probability
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Note (1): from Sousa et al. (2008, Cat. J/A+A/487/373);
Adibekyan et al. (2012A&A...543A..89A 2012A&A...543A..89A);
Delgado Mena et al. (2017, Cat. J/A+A/606/A94).
Note (2): Galactic affiliation probability PGal (i.e. probability of affiliation
to the thin disk PGal∼1 or thick disk PGal∼0).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 27-Jan-2021