TY - JOUR
T1 - Cold Jupiters and improved masses in 38 Kepler and K2 small-planet systems from 3661 high-precision HARPS-N radial velocities. No excess of cold Jupiters in small-planet systems
AU - Bonomo, A. S.
AU - Dumusque, X.
AU - Massa, A.
AU - Mortier, A.
AU - Bongiolatti, R.
AU - Malavolta, L.
AU - Sozzetti, A.
AU - Buchhave, L. A.
AU - Damasso, M.
AU - Haywood, R. D.
AU - Morbidelli, A.
AU - Latham, D. W.
AU - Molinari, E.
AU - Pepe, F.
AU - Poretti, E.
AU - Udry, S.
AU - Affer, L.
AU - Boschin, W.
AU - Charbonneau, D.
AU - Cosentino, R.
AU - Cretignier, M.
AU - Ghedina, A.
AU - Lega, E.
AU - López-Morales, M.
AU - Margini, M.
AU - Fiorenzano, A. F. Martínez
AU - Mayor, M.
AU - Micela, G.
AU - Pedani, M.
AU - Pinamonti, M.
AU - Rice, K.
AU - Sasselov, D.
AU - Tronsgaard, R.
AU - Vanderburg, A.
N1 - 21 pages, 10 figures, 10 tables, accepted for publication in Astronomy and Astrophysics on 6 April 2023
PY - 2023/8/29
Y1 - 2023/8/29
N2 - The exoplanet population characterized by relatively short orbital periods (P
< 100 d) around solar-type stars is dominated by super-Earths and
sub-Neptunes. However, these planets are missing in our Solar System and
the reason behind this absence is still unknown. Two theoretical
scenarios invoke the role of Jupiter as the possible culprit: Jupiter
may have acted as a dynamical barrier to the inward migration of
sub-Neptunes from beyond the water iceline; alternatively, Jupiter may
have considerably reduced the inward flux of material (pebbles) required
to form super-Earths inside that iceline. Both scenarios predict an
anti-correlation between the presence of small planets and that of cold
Jupiters in exoplanetary systems. To test that prediction, we
homogeneously analyzed the radial-velocity measurements of 38 Kepler and
K2 transiting small planet systems gathered over nearly ten years with
the HARPS-N spectrograph, as well as publicly available radial
velocities collected with other facilities. We used Bayesian
differential evolution Markov chain Monte Carlo techniques, which in
some cases were coupled with Gaussian process regression to model
non-stationary variations due to stellar magnetic activity phenomena. We
detected five cold Jupiters in three systems: two in Kepler-68, two in
Kepler-454, and a very eccentric one in K2-312. We also found linear
trends caused by bound companions in Kepler-93, Kepler-454, and K2-12,
with slopes that are still compatible with a planetary mass for outer
bodies in the Kepler-454 and K2-12 systems. By using binomial statistics
and accounting for the survey completeness, we derived an occurrence
rate of 9.3−2.9+7.7% for cold Jupiters with 0.3–13 MJup and 1–10 AU, which is lower but still compatible at 1.3σ
with the value measured from radial-velocity surveys for solar-type
stars, regardless of the presence or absence of small planets. The
sample is not large enough to draw a firm conclusion about the predicted
anti-correlation between small planets and cold Jupiters; nevertheless,
we found no evidence of previous claims of an excess of cold Jupiters
in small planet systems. As an important byproduct of our analyses, we
homogeneously determined the masses of 64 Kepler and K2 small planets,
reaching a precision better than 5, 7.5, and 10σ for 25, 13, and 8
planets, respectively. Finally, we release the 3661 HARPS-N radial
velocities used in this work to the scientific community. These
radial-velocity measurements mainly benefit from an improved data
reduction software that corrects for subtle prior systematic effects.
AB - The exoplanet population characterized by relatively short orbital periods (P
< 100 d) around solar-type stars is dominated by super-Earths and
sub-Neptunes. However, these planets are missing in our Solar System and
the reason behind this absence is still unknown. Two theoretical
scenarios invoke the role of Jupiter as the possible culprit: Jupiter
may have acted as a dynamical barrier to the inward migration of
sub-Neptunes from beyond the water iceline; alternatively, Jupiter may
have considerably reduced the inward flux of material (pebbles) required
to form super-Earths inside that iceline. Both scenarios predict an
anti-correlation between the presence of small planets and that of cold
Jupiters in exoplanetary systems. To test that prediction, we
homogeneously analyzed the radial-velocity measurements of 38 Kepler and
K2 transiting small planet systems gathered over nearly ten years with
the HARPS-N spectrograph, as well as publicly available radial
velocities collected with other facilities. We used Bayesian
differential evolution Markov chain Monte Carlo techniques, which in
some cases were coupled with Gaussian process regression to model
non-stationary variations due to stellar magnetic activity phenomena. We
detected five cold Jupiters in three systems: two in Kepler-68, two in
Kepler-454, and a very eccentric one in K2-312. We also found linear
trends caused by bound companions in Kepler-93, Kepler-454, and K2-12,
with slopes that are still compatible with a planetary mass for outer
bodies in the Kepler-454 and K2-12 systems. By using binomial statistics
and accounting for the survey completeness, we derived an occurrence
rate of 9.3−2.9+7.7% for cold Jupiters with 0.3–13 MJup and 1–10 AU, which is lower but still compatible at 1.3σ
with the value measured from radial-velocity surveys for solar-type
stars, regardless of the presence or absence of small planets. The
sample is not large enough to draw a firm conclusion about the predicted
anti-correlation between small planets and cold Jupiters; nevertheless,
we found no evidence of previous claims of an excess of cold Jupiters
in small planet systems. As an important byproduct of our analyses, we
homogeneously determined the masses of 64 Kepler and K2 small planets,
reaching a precision better than 5, 7.5, and 10σ for 25, 13, and 8
planets, respectively. Finally, we release the 3661 HARPS-N radial
velocities used in this work to the scientific community. These
radial-velocity measurements mainly benefit from an improved data
reduction software that corrects for subtle prior systematic effects.
KW - Planetary systems
KW - planets and satellites: detection
KW - planets and satellites: formation
KW - techniques: radial veolcities
KW - methods: statistical
U2 - 10.1051/0004-6361/202346211
DO - 10.1051/0004-6361/202346211
M3 - Article
SN - 0004-6361
VL - 677
SP - 1
EP - 18
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A33
ER -