J/A+A/615/A175 Solar system analogs with HARPS (Barbato+, 2018)
Exploring the realm of scaled solar system analogs with HARPS.
Barbato D., Sozzetti A., Desidera S., Damasso M., Bonomo A.S.,
Giacobbe P., Colombo L.S., Lazzoni C., Claudi R., Gratton R.,
LoCurto G., Marzari F., Mordasini C.
<Astron. Astrophys. 615, A175 (2018)>
=2018A&A...615A.175B 2018A&A...615A.175B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Exoplanets ;
Stars, G-type ; Radial velocities
Keywords: techniques: radial velocities - methods: data analysis -
planetary systems - stars: individual: HD 50499 -
stars: individual: HD 73267
Abstract:
The assessment of the frequency of planetary systems reproducing the
solar system's architecture is still an open problem in exoplanetary
science. Detailed study of multiplicity and architecture is generally
hampered by limitations in quality, temporal extension and observing
strategy, causing difficulties in detecting low-mass inner planets in
the presence of outer giant planets.
We present the results of high-cadence and high-precision HARPS
observations on 20 solar-type stars known to host a single long-period
giant planet in order to search for additional inner companions and
estimate the occurence rate fp of scaled solar system analogues -
in other words, systems featuring lower-mass inner planets in the
presence of long-period giant planets.
We carried out combined fits of our HARPS data with literature radial
velocities using differential evolution MCMC to refine the literature
orbital solutions and search for additional inner planets. We then
derived the survey detection limits to provide preliminary estimates
of fp.
We generally find better constrained orbital parameters for the known
planets than those found in the literature; significant updates can be
especially appreciated on half of the selected planetary systems.
While no additional inner planet is detected, we find evidence for
previously unreported long-period massive companions in systems HD
50499 and HD 73267. We finally estimate the frequency of inner low
mass (10-30M{earth}) planets in the presence of outer giant planets
as fp<9.84% for P<150-days.
Our preliminary estimate of fp is significantly lower than the
literature values for similarly defined mass and period ranges; the
lack of inner candidate planets found in our sample can also be seen
as evidence corroborating the inwards-migration formation model for
super-Earths and mini-Neptunes. Our results also underline the need
for high-cadence and high-precision followup observations as the key
to precisely determine the occurence of solar system analogues.
Description:
We carried out high-cadence and high-precision HARPS observations of
20 Solar-type stars orbited by a single known long-period giant planet
in order to search for additional inner lower-mass companions. For
each of the sample stars and each datapoint epoch of observation,
exposure time, radial velocity measurement, RV error, bisector,
full-width at half-maximum, CaII and its error, Halpha and its error,
air mass and signal-to-noise ratio are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 65 20 List of studied stars
table22.dat 113 563 HARPS radial velocity measurements and associated
exposure times, activity indexes and SNR
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Host star name
13- 14 I2 h RAh Simbad right ascension (J2000.0)
16- 17 I2 min RAm Simbad right ascension (J2000.0)
19- 23 F5.2 s RAs Simbad right ascension (J2000.0)
25 A1 --- DE- Simbad declination sign (J2000.0)
26- 27 I2 deg DEd Simbad declination (J2000.0)
29- 30 I2 arcmin DEm Simbad declination (J2000.0)
32- 35 F4.1 arcsec DEs Simbad declination (J2000.0)
37- 41 F5.3 mag Bmag Simbad B band magnitude
43- 46 F4.2 mag Vmag Simbad V band magnitude
49- 61 A13 --- SpType Simbad MK spectral type
64- 65 I2 --- N Number of measurements in table22.dat
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Byte-by-byte Description of file: table22.dat
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Bytes Format Units Label Explanations
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1- 9 A9 ---- Star Host star name
12- 25 F14.6 d BJD Epoch of radial velocity
28- 30 I3 s Texp Exposure time
33- 40 F8.4 km/s RV Radial velocity
43- 48 F6.4 km/s e_RV Radial velocity uncertainty
51- 56 F6.3 km/s BIS Bisector inverse span
59- 63 F5.3 km/s FWHM CCF full-width at half-maximum
66- 72 F7.5 ---- CaII CaII (S-index Mount Wilson)
75- 81 F7.5 ---- e_CaII CaII uncertainty
84- 90 F7.5 ---- Halpha Halpha index
93- 99 F7.5 ---- e_Halpha Halpha index uncertainty
102-105 F4.2 ---- Airmass Air mass at exposure start
108-113 F6.2 ---- SNR Signal-to-noise ratio of RV
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Acknowledgements:
Domenico Barbato, barbato(at)oato.inaf.it
(End) Patricia Vannier [CDS] 24-Apr-2018