J/AJ/158/81 Low-mass stars from the first two TESS sectors (Cloutier, 2019)
The independent discovery of planet candidates around low-mass stars and
astrophysical false positives from the first two TESS sectors.
Cloutier R.
<Astron. J., 158, 81 (2019)>
=2019AJ....158...81C 2019AJ....158...81C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Photometry ; Optical ; Photometry, infrared ;
Parallaxes, trigonometric ; Stars, distances ; Stars, diameters ;
Effective temperatures ; Stars, masses ; Exoplanets
Keywords: methods: data analysis - planets and satellites: detection -
planets and satellites: fundamental parameters -
planets and satellites: terrestrial planets - stars: low-mass -
techniques: photometric
Abstract:
Continuous data releases throughout the Transiting Exoplanet Survey
Satellite (TESS) primary mission will provide unique opportunities for
the exoplanet community at large to contribute to maximizing TESS's
scientific return via the discovery and validation of transiting planets.
This paper introduces our independent pipeline for the detection of
periodic transit events along with the results of its inaugural application
to the recently released 2 minute light curves of low-mass stars from
the first two TESS sectors. The stellar parameters within our sample are
refined using precise parallax measurements from the Gaia DR2 (Cat. I/345),
which reduce the number of low-mass stars in our sample relative to those
listed in the TESS Input Catalog. In lieu of the follow-up observations
required to confirm or refute the planetary nature of transit-like signals,
a validation of transit-like events flagged by our pipeline is performed
statistically. The resulting vetted catalog contains eight probable blended
eclipsing binaries, eight known TOIs, plus seven new planet candidates
(PCs) smaller than 4 Earth radii. This work demonstrates the ability of
our pipeline to detect sub-Neptune-sized PCs, which to date represent some
of the most attractive targets for future atmospheric characterization
via transmission or thermal emission spectroscopy and for radial velocity
efforts aimed at the completion of the TESS level one requirement to
deliver 50 planets smaller than 4 Earth radii with measured masses.
Description:
Our initial stellar sample is retrieved from version 7 of the TESS
Input Catalog (TIC-7), which is accessed via the Barbara A. Mikulski
Archive for Space Telescope (MAST) Portal
(http://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html).
To identify putative low-mass dwarf stars within the TIC-7, we first
restrict our sample to sources flagged as dwarf stars based on their
2MASS colors and the reduced proper motion criterion from Stassun et al.
(2018, J/AJ/156/102), modified from Collier Cameron et al.
(2007MNRAS.380.1230C 2007MNRAS.380.1230C). We further restrict our sample to stars whose
"priority" is ≥10-3, where the TIC priority metric is based on the
relative probability of detecting small planetary transits. As such,
the priority is dependent on Rs, the expected photometric precision,
the number of TESS sectors in which the TIC member will be visible,
and its contamination ratio, which is the ratio of contamination to
source flux where contamination is computed over 10 TESS pixels from
the source (∼3.5 arcmin).
Our final stellar sample contains 1599 low-mass stars with 537, 694,
and 368 observed within TESS sectors 1, 2, and both, respectively.
Photometric measurements and fundamental stellar parameters for our
final stellar sample are reported in Tables 1 and 2, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 1599 Stellar photometry for the 1599 TICs in our sample
of low mass stars
table2.dat 115 1599 Stellar parameters for the 1599 TICs in our sample
of low mass stars
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJ/809/77 : Transiting Exoplanet Survey Satellite (TESS) (Sullivan+, 2015)
J/ApJS/216/7 : Planets Around Low-Mass Stars (PALMS). IV. (Bowler+, 2015)
J/AJ/155/180 : A catalog of cool dwarf targets for the TESS (Muirhead+, 2018)
J/AJ/156/102 : The TESS Input Catalog and Candidate Target List
(Stassun+, 2018)
J/ApJS/239/2 : Simulated exoplanets from TESS list of targets (Barclay+, 2018)
J/AJ/157/113 : TESS M-dwarf exoplanetary systems (Ballard, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC [2733611/471016669] TESS Input Catalog identifier
11- 16 F6.3 mag Tmag [7.019/15.82] Apparent TESS magnitude
18- 23 F6.3 mag GBPmag [7.098/15.862] Apparent Gaia blue passband
magnitude
25- 29 F5.3 mag e_GBPmag [0/0.065] Uncertainty in GBPmag
31- 36 F6.3 mag GRPmag [9.179/19.383] Apparent Gaia red passband
magnitude
38- 42 F5.3 mag e_GRPmag [0/0.065] Uncertainty in GRPmag
44- 49 F6.3 mag Jmag [5.669/13.801] Apparent 2MASS J band magnitude
51- 55 F5.3 mag e_Jmag [0.017/0.056] Uncertainty in Jmag
57- 62 F6.3 mag Hmag [5.108/13.293] Apparent 2MASS H band magnitude
64- 68 F5.3 mag e_Hmag [0.017/0.069] Uncertainty in Hmag
70- 75 F6.3 mag Ksmag [4.8/12.914] Apparent 2MASS KS band magnitude
77- 81 F5.3 mag e_Ksmag [0.015/0.051] Uncertainty in Ksmag
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- TIC [2733611/471016669] TESS Input Catalog
identifier
11- 18 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
20- 27 F8.4 deg DEdeg Declination in decimal degrees (J2000)
29- 35 F7.3 mas plx [3.58/130.332] Gaia DR2 parallax
37- 41 F5.3 mas e_plx [0.012/1.307] Uncertainty in plx
43- 49 F7.3 pc Dist [7.673/279.33] Distance from plx
51- 55 F5.3 pc e_Dist [0.002/8.9] Uncertainty in Dist
57- 61 F5.3 mag KsMag [5.001/8.877] Absolute 2MASS KS band
magnitude
63- 67 F5.3 mag e_KsMag [0.016/0.165] Uncertainty in KsMag
69- 74 F6.4 Rsun R* [0.1506/0.6114] Stellar radius
76- 81 F6.4 Rsun e_R* [0.0045/0.0324] Uncertainty in R*
83- 86 I4 K Teff [2737/4042] Stellar effective temperature
88- 89 I2 K e_Teff [49/70] Uncertainty in Teff
91- 96 F6.4 Msun M* [0.1192/0.6347] Stellar mass
98-103 F6.4 Msun e_M* [0.0015/0.0308] Uncertainty in M*
105-109 F5.3 [cm/s2] log(g) [4.668/5.158] Log stellar surface gravity
111-115 F5.3 [cm/s2] e_log(g) [0.026/0.061] Uncertainty in log(g)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 01-Oct-2019