J/A+A/667/A63 RV Survey for Planets around Young stars (Zakhozhay+, 2022)
Radial Velocity Survey for Planets around Young stars. (RVSPY).
Target characterisation and high-cadence survey.
Zakhozhay O.V., Launhardt R., Mueller A., Brems S., Eigenthaler P.,
Gennaro M., Hempel A., Hempel M., Henning T., Kennedy G., Kim S.,
Kuerster M., Lachaume R., Manerikar Y., Patel J., Pavlov A., Reffert S.,
Trifonov T.
<Astron. Astrophys. 667, A63 (2022)>
=2022A&A...667A..63Z 2022A&A...667A..63Z (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Stars, nearby ; Radial velocities ; Optical
Stars, double and multiple ; Exoplanets
Keywords: methods: observational - techniques: radial velocities -
surveys - planets and satellites: detection - stars: activity -
planetary systems
Abstract:
The occurrence rate and period distribution of (giant) planets around
young stars is still not as well constrained as for older
main-sequence stars. This is mostly due to the intrinsic
activity-related complications and the avoidance of young stars in
many large planet search programmes. Yet, dynamical restructuring
processes in planetary systems may last significantly longer than the
actual planet formation phase and may well extend long into the debris
disc phase, such that the planet populations around young stars may
differ from those observed around main-sequence stars.
We introduce our Radial Velocity Survey for Planets around Young stars
(RVSPY), which is closely related to the NaCo-ISPY direct imaging
survey, characterise our target stars, and search for substellar
companions at orbital separations smaller than a few au from the host
star.
We used the FEROS spectrograph, mounted to the MPG/ESO 2.2m telescope
in Chile, to obtain high signal-to-noise spectra and time series of
precise radial velocities (RVs) of 111 stars, most of which are
surrounded by debris discs. Our target stars have spectral types
between early F and late K, a median age of 400Myr, and a median
distance of 45pc. During the initial reconnaissance phase of our
survey, we determined stellar parameters and used high-cadence
observations to characterise the intrinsic stellar activity, searched
for hot companions with orbital periods of up to 10 days, and derived
the detection thresholds for longer-period companions. In our analysis
we, have included archival spectroscopic data, spectral energy
distribution, and data for photometric time series from the TESS
mission.
For all target stars we determined their basic stellar parameters and
present the results of the high-cadence RV survey and activity
characterisation. We have achieved a median single-measurement RV
precision of 6m/s and derived the short-term intrinsic RV scatter of
our targets (median 23m/s), which is mostly caused by stellar
activity and decays with an age from >100m/s at <20Myr to <20m/s at
>500Myr. We analysed time series periodograms of the high-cadence RV
data and the shape of the individual cross-correlation functions. We
discovered six previously unknown close companions with orbital
periods between 10 and 100 days, three of which are low-mass stars,
and three are in the brown dwarf mass regime. We detected no hot
companion with an orbital period <10 days down to a median mass limit
of ∼1M{Jup} for stars younger than 50Myr, which is still compatible
with the established occurrence rate of such companions around
main-sequence stars. We found significant RV periodicities between 1.3
and 4.5 days for 14 stars, which are, however, all caused by
rotational modulation due to starspots. We also analysed the data for
TESS photometric time series and found significant periodicities for
most of the stars. For 11 stars, the photometric periods are also
clearly detected in the RV data. We also derived stellar rotation
periods ranging from 1 to 10 days for 91 stars, mostly from the TESS
data. From the intrinsic activity-related short-term RV jitter, we
derived the expected mass-detection thresholds for longer-period
companions, and selected 84 targets for the longer-term RV monitoring.
Description:
Target list and basic stellar parameters of the Radial Velocity Survey
for Planets around Young stars (RVSPY) stars with debris discs
(tablea1.dat) and stars without disc excess (tablea2.dat).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 254 93 Target list and basic stellar parameters of
debris disc stars
tablea2.dat 209 18 Target list and basic stellar parameters of
stars without disc excess
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Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Stellar ID
13- 17 F5.1 pc d Distance, inferred from Gaia DR2 parallaxes
with the method described in Bailer-Jones et
al., 2018AJ....156...58B 2018AJ....156...58B, Cat. I/347
20- 24 F5.2 mag Vmag Visual magnitude, taken from The Hipparcos,
Tycho Catalogues and from SIMBAD
29- 33 A5 --- SpType Spectral type from SIMBAD
38- 41 I4 K Teff-sp Stellar effective temperature (2)
46- 49 I4 K Teff-ph Stellar effective temperature (3)
54- 58 F5.2 --- [Fe/H] Stellar metallicity (2)
63- 66 F4.2 [cm/s2] logg Stellar surface gravity (2)
71- 74 F4.2 Msun Mass Stellar mass (4)
78- 82 F5.2 Lsun Lum Photometric luminosity (3)
86 A1 --- l_vsini Limit flag in vsini
87- 90 F4.1 km/s vsini Rotational velocity (2)
95-102 A8 --- Assoc Association membership with the probability of
>80% according to BANYAN Sigma (5)
103 A1 --- n_Assoc [*] Note on Assoc (1)
107-110 F4.2 [Myr] logAge Age from the literature
113-116 F4.2 [Myr] e_logAge Age uncertainty from the literature
120-148 A29 --- Notes Notes to individual objects
152-254 A103 --- Ref References for the ages (6)
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Note (1): *: HD10008 is a BPMG member based on kinematic properties only
(Banyan Sigma: >90, 2Gagne et al., 2018ApJ...856...23G 2018ApJ...856...23G, Cat. J/ApJ/856/23),
but low vsini and chemical age (Delgado Mena et al., 2019A&A...624A..78D 2019A&A...624A..78D,
Cat. J/A+A/624/A78) both contradict the young age and BPMG membership
Note (2): derived from FEROS spectra with the ZASPE pipeline
(Brahm et al., 2017MNRAS.467..971B 2017MNRAS.467..971B).
Note (3): derived by fitting stellar atmosphere models (PHOENIX; Husser et al.,
2013A&A...553A...6H 2013A&A...553A...6H) to observed photometry compiled from various data bases
(see Sect. 3.2).
Note (4): derived HRD isochrone fits as described in Sect.3.2.
Typical (median) 1-sigma uncertainties are 0.035M☉.
Note (5): association abbreviations from Gagne et al. (2018ApJ...856...23G 2018ApJ...856...23G,
Cat. J/ApJ/856/23) as follows:
ABDMG = AB Doradus
ARG = Argus
BPMG = beta Pictoris
COL = Columba
LCC = Lower Centaurus Crux
PLE = Pleiades cluster
THA = Tucana-Horologium association
UCL = Upper Centaurus Lupus
USCO = Upper Scorpius
Note (6): References:
2006AJ....131.1702T 2006AJ....131.1702T = Torres, Cat. J/AJ/131/1702
2008ApJ...687.1264M 2008ApJ...687.1264M = Mamajek & Hillenbrand, Cat. J/ApJ/687/1264
2009yCat.5130....0H 2009yCat.5130....0H = Holmberg et al., 2009A&A...501..941H 2009A&A...501..941H, Cat. V/130
2011A&A...530A.138C 2011A&A...530A.138C = Casagrande et al., Cat. J/A+A/530/A138
2011MNRAS.410..190T 2011MNRAS.410..190T = Tetzlaff et al., Cat. J/MNRAS/410/190
2012AJ....143..135V 2012AJ....143..135V = Vican, Cat. J/AJ/143/135
2013ApJ...768...25G 2013ApJ...768...25G = Gaspar et al., Cat. J/ApJ/768/25
2014ApJS..211...25C 2014ApJS..211...25C = Chen et al., Cat. J/ApJS/211/25
2015ApJ...804..146D 2015ApJ...804..146D = David & Hillenbrand, Cat. J/ApJ/804/146
2015ApJ...813..108D 2015ApJ...813..108D = Dahm
2015MNRAS.454..593B 2015MNRAS.454..593B = Bell et al., Cat. J/MNRAS/454/593
2016MNRAS.461..794P 2016MNRAS.461..794P = Pecaut & Mamajek, Cat. J/MNRAS/461/794
2017MNRAS.470.3606H 2017MNRAS.470.3606H = Holland et al.
2018AJ....156..286S 2018AJ....156..286S = Stone et al., Cat. J/AJ/156/286
2019A&A...624A..78D 2019A&A...624A..78D = Delgado Mena et al., Cat. J/A+A/624/A78
2019ApJ...870...27Z 2019ApJ...870...27Z = Zuckerman
2020ApJ...898...27S 2020ApJ...898...27S = Stanford-Moore et al., Cat. J/ApJ/898/27
2022A&A...659A.135P 2022A&A...659A.135P = Pearce et al., Cat. J/A+A/659/A135
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Acknowledgements:
Olga Zakhozhay, zakhozhay(at)mpia.de
(End) Olga Zakhozhay [MPIA, Heidelberg], Patricia Vannier [CDS] 01-Sep-2022