J/AJ/163/80 The Scorpion Planet Survey; A-stars IR spectroscopy (Wagner+, 2022)
The Scorpion Planet Survey; Wide-orbit Giant Planets Around Young A-type Stars.
Wagner K., Apai D., Kasper M., McClure M., Robberto M.
<Astron. J., 163, 80 (2022)>
=2022AJ....163...80W 2022AJ....163...80W
ADC_Keywords: Stars, A-type; Exoplanets; Spectra, infrared; Spectral types
Keywords: Exoplanets ; Exoplanet formation ; Exoplanet systems ; Early-
type stars ; Direct imaging ; Coronagraphic imaging
Abstract:
The first directly imaged exoplanets indicated that wide-orbit giant
planets could be more common around A-type stars. However, the
relatively small number of nearby A-stars has limited the precision of
exoplanet demographics studies to ≳10%. We aim to constrain the
frequency of wide-orbit giant planets around A-stars using the
VLT/SPHERE extreme adaptive optics system, which enables targeting
≲100 A-stars between 100 and 200pc. We present the results of a
survey of 84 A-stars within the nearby ∼5-17Myr old ScoOB2
association. The survey detected three companions-one of which is a
new discovery (HIP75056Ab), whereas the other two (HD95086b and
HIP65426b) are now-known planets that were included without a priori
knowledge of their existence. We assessed the image sensitivity and
observational biases with injection and recovery tests combined with
Monte Carlo simulations to place constraints on the underlying
demographics. We measure a decreasing frequency of giant planets with
increasing separation, with measured values falling between 10% and 2%
for separations of 30-100au, and 95% confidence-level upper limits of
≲45%-8% for planets on 30-100au orbits, and ≲5% between 200 and
500au. These values are in excellent agreement with recent surveys of
A-stars in the solar neighborhood-supporting findings that giant
planets out to separations of ≲100 au are more frequent around
A-stars than around solar-type hosts. Finally, the relatively low
occurrence rate of super-Jupiters on wide orbits, the positive
correlation with stellar mass, and the inverse correlation with
orbital separation are consistent with core accretion being their
dominant formation mechanism.
Description:
Our observations utilized the Spectro-Polarimetric High-Contrast
Exoplanet Research Experiment (SPHERE) instrument on the Very Large
Telescope (VLT) in Chile. SPHERE provides contrasts of 10-5--10-6
at separations of ∼1" in under an hour for ∼7--8mag stars. SPHERE also
provides diffraction-limited imaging with a resolution of ∼0.05"
across wavelengths of ∼1--2.2µm. Dual-band imaging in a selection
of narrow-band filters over a field of view of ∼6" in radius (IRDIS)
is combined with simultaneous integral field spectroscopy from
0.95--1.65µm over a smaller field of view of 0.8" in radius (IFS).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 89 141 Targets Sco-Cen A-type Stars
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)
J/A+A/430/137 : Close visual companions in Scorpius OB2 (Kouwenhoven+, 2005)
J/ApJ/794/159 : Statistical analysis of exoplanet surveys (Brandt+, 2014)
J/other/Sci/350.64 : 51 Eri b near-infrared spectrum (Macintosh+, 2015)
J/ApJ/831/125 : ALMA 887µm obs. ChaI star-forming region (Pascucci+, 2016)
J/MNRAS/461/794 : Scorpius-Centaurus K-Type Stars (Pecaut+, 2016)
J/A+A/605/L9 : NIR spectrum of exoplanet HIP 65426b (Chauvin+, 2017)
J/ApJ/860/109 : Keck HIRES obs. 245 subgiants (Ghezzi+, 2018)
J/AJ/156/286 : The LEECH exoplanet imaging survey (Stone+, 2018)
J/AJ/158/13 : The first 300 stars observed by the GPIES (Nielsen+, 2019)
J/AJ/159/63 : AO obs. exoplanets & brown dwarf companions (Bowler+, 2020)
J/A+A/648/A73 : Discovery of the directly imaged planet YSES 2b (Bohn+, 2021)
J/A+A/646/A164 : BEAST sample properties (Janson+, 2021)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Target [1/88] Target identification number
4- 5 I2 h RAh [10/17] Hour of right ascension (J2000)
7- 8 I2 min RAm Minute of right ascension (J2000)
10- 13 F4.1 s RAs Second of right ascension (J2000)
15 A1 --- DE- [-] Sign of declination (J2000)
16- 17 I2 deg DEd [20/72]? Degree of declination (J2000)
19- 20 I2 arcmin DEm Arcminute of declination (J2000)
22- 23 I2 arcsec DEs Arcsecond of declination (J2000)
25- 29 I5 --- HIP HIP number
31- 34 F4.2 mag Ksmag [5.21/8.29] Ks-band magnitude
36- 43 A8 --- SpT Spectral type
45- 47 A3 --- Group Subgroup (1)
49- 52 I4 yr Obs.Y [2015/2019] Year of observation
54- 55 I2 "month" Obs.M Month of observation
57- 58 I2 d Obs.D Day of observation
60- 64 F5.1 min Texp [16.4/101] Exposure time
66- 72 F7.3 deg Field [0.25/355] Rotation field
74- 76 A3 --- Filt Filter used; J, H, K and Y
78- 82 F5.2 s DIT [4/96] Detector Integration Time
84- 89 A6 --- Survey Survey identifier (2)
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Note (1): Subgroups as follows:
LCC = Lower Centaurus Crux (46 occurrences)
UCL = Upper Centaurus Lupus (79 occurrences)
US = Upper Scorpius(16 occurrences)
Note (2): Survey IDs were assigned in numerical order as observations
were completed, except for those obtained from the archive (those
beginning with "SA".
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 06-May-2022