J/AJ/156/82 Radial velocity characterization of TESS planets (Cloutier+, 2018)
Quantifying the observational effort required for the radial velocity
characterization of TESS planets.
Cloutier R., Doyon R., Bouchy F., Hebrard G.
<Astron. J., 156, 82 (2018)>
=2018AJ....156...82C 2018AJ....156...82C (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, bright ; Radial velocities ; Stars, masses ;
Effective temperatures ; Stars, distances ; Photometry, UBVRI ;
Photometry, infrared ; Rotational velocities ; Models
Keywords: methods: analytical - planets and satellites: detection -
planets and satellites: fundamental parameters -
techniques: radial velocities
Abstract:
The Transiting Exoplanet Survey Satellite (TESS) will conduct a two-year
wide-field survey searching for transiting planets around bright stars.
Many TESS discoveries will be amenable to mass characterization via
ground-based radial velocity measurements with any of a growing suite
of existing and anticipated velocimeters in the optical and near-infrared.
In this study we present an analytical formalism to compute the number
of radial velocity (RV) measurements - and hence the total observing
time-required to characterize RV planet masses with the inclusion of
either a white or correlated noise activity model. We use our model to
calculate the total observing time required to measure all TESS planet
masses from the expected TESS planet yield while relying on our current
understanding of the targeted stars, stellar activity, and populations
of unseen planets that inform the expected RV precision. We also present
specialized calculations applicable to a variety of interesting subsets
of TESS planets including the characterization of 50 planets smaller
than 4 Earth radii, which is expected to take as little as 60 nights
of observation. However, the efficient RV characterization of such planets
requires a priori knowledge of the "best" targets, which we argue can be
identified prior to the conclusion of the TESS planet search based on our
calculations. Our results highlight the comparable performance of optical
and near-IR spectrographs for most planet populations except for Earths
and temperate TESS planets, which are more efficiently characterized in
the near-IR. Lastly, we present an online tool to the community to compute
the total observing times required to detect any transiting planet using
a user-defined spectrograph (RVFC; http://maestria.astro.umontreal.ca/rvfc).
Description:
NASA's Transiting Exoplanet Survey Satellite (TESS; Ricker et al.
2015JATIS...1a4003R 2015JATIS...1a4003R), launched in 2018 April, is conducting a wide-field
survey over a period of at least two years and is expected to discover
approximately 1700 new transiting exoplanet candidates at a 2 minute
cadence around nearby stars over nearly the entire sky (Sullivan et al.
2015, J/ApJ/809/77, hereafter S15). Due to their proximity, many
candidate TESS planetary systems, or TESS objects of interest (TOIs),
will be amenable to precision radial velocity (RV) observations using
ground-based velocimeters to establish their planetary nature and to
measure the masses of identified planets.
Given the large number of velocimeters that can be used for RV
characterization of TESS planet masses it is useful to understand the
observational effort required to do so. That is, how many RV
measurements - and what total observing time - are required to detect the
masses of the TESS planets at a given significance. Furthermore, it is
critical to access which spectrographs are best suited to the efficient
mass characterization of each transiting planet found with TESS. To
address these questions, we present here an analytical formalism to
compute the number of RV measurements required to detect a transiting
planet's mass and apply it to the expected TESS planet yield from S15.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 38 31 Summary of RV observations for known transiting
planets with white RV noise
table3.dat 66 5 Summary of RV observations for known transiting
planets with red RV noise
table5.dat 105 1984 Stellar parameters from the Sullivan et al.
(2015, J/ApJ/809/77; S15) synthetic catalog
table6.dat 93 1984 Median radial velocity noise sources and
follow-up calculations for 3σ planet mass
detections of the S15 synthetic catalog
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See also:
J/ApJ/785/126 : HIRES radial velocity measurements (Knutson+, 2014)
J/ApJ/800/135 : HARPS-N radial velocities of KOI-69 (Dressing+, 2015)
J/ApJ/809/77 : Transiting Exoplanet Survey Satellite (TESS) (Sullivan+, 2015)
J/AJ/152/204 : HARPS-N radial velocities of HD 179070 (Lopez-Morales+, 2016)
J/A+A/608/A35 : K2-18 HARPS time-series (Cloutier+, 2017)
J/ApJS/239/2 : Simulated exoplanets from TESS list of targets (Barclay+, 2018)
http://tess.mit.edu/ : TESS home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Planetary system name
12 A1 --- n_Name [a] Note on Name (1)
14- 18 F5.2 m/s sig(eff) [1.86/66] Effective RV uncertainty
20- 24 F5.2 m/s sig(K) [0.27/17.5] Precision of K measurement
26- 28 I3 --- N(RV-act) [4/220] Actual number of radial velocities
30- 35 F6.2 --- N(RV-calc) [4/218] Calculated number of radial
velocities
37- 38 I2 --- Ref [1/10] Reference (2)
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Note (1): Note as follows:
a = HARPS-N measurements only.
Note (2): Reference as follows:
1 = Berta-Thompson et al. (2015Natur.527..204B 2015Natur.527..204B);
2 = Charbonneau et al. (2009Natur.462..891C 2009Natur.462..891C);
3 = Knutson et al. (2014, J/ApJ/785/126);
4 = Howard et al. (2011ApJ...730...10H 2011ApJ...730...10H);
5 = Bouchy et al. (2005A&A...444L..15B 2005A&A...444L..15B);
6 = Vanderburg et al. (2015ApJ...800...59V 2015ApJ...800...59V);
7 = Weiss et al. (2016ApJ...819...83W 2016ApJ...819...83W);
8 = Howard et al. (2013Natur.503..381H 2013Natur.503..381H);
9 = Dressing et al. (2015, J/ApJ/800/135);
10 = Burke et al. (2007ApJ...671.2115B 2007ApJ...671.2115B).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Planetary system name
11- 14 F4.2 m/s K [1.86/5.3] Radial velocity semi-amplitude
16- 18 F3.1 m/s a [2.8/9] Amplitude of the correlations
20- 24 F5.1 d lambda [17/277.9] Exponential timescale λ
26- 28 F3.1 --- Gamma [1/2.5] Coherence parameter Γ
30- 34 F5.1 d PGP [12.6/134] Periodic timescale PGP
(for the Gaussian process model function)
36- 39 F4.2 m/s sig(jit) [0.25/3.44] Additive scalar jitter parameter
41- 44 F4.2 m/s sig(eff) [1.85/9.33] Effective RV uncertainty
46- 49 F4.2 m/s sig(K) [0.25/1.1] Precision of K measurement
51- 53 I3 --- N(RV-act) [71/144] Actual number of radial velocities
55- 59 F5.1 --- N(RV-med) [61.4/265.5] Median calculated number of
radial velocities
61- 64 F4.1 --- e_N(RV-med) [2.7/64.4] Uncertainty in N(RV-med)
66 I1 --- Ref [1/5] Reference (1)
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Note (1): Reference as follows:
1 = Haywood et al. (2014MNRAS.443.2517H 2014MNRAS.443.2517H);
2 = Cloutier et al. (2017, J/A+A/608/A35);
3 = Lopez-Morales et al. (2016, J/AJ/152/204);
4 = Grunblatt et al. (2015ApJ...808..127G 2015ApJ...808..127G);
5 = Dittmann et al. (2017Natur.544..333D 2017Natur.544..333D).
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- TOI [0/1983]? TESS object-of-interest identifier
6- 11 F6.2 deg RAdeg Right Ascension in decimal degrees (J2000)
13- 18 F6.2 deg DEdeg Declination in decimal degrees (J2000)
20- 26 F7.3 d Per [0.5/224.7] Period
28- 32 F5.2 Mgeo Mp [0.3/47.56] Planetary mass
34- 38 F5.2 m/s K [0.3/28.04] Radial velocity semi-amplitude
40- 46 F7.1 Earth Sp [0.1/55380] Irradiance recieved by planet,
in Earth units
48- 51 F4.2 Msun M* [0.03/3.33] Stellar mass
53- 57 I5 K Teff [2529/11910] Effective temperature
59- 63 F5.1 pc Dist [3.8/478.6] Distance
65- 69 F5.2 mag Bmag [4.68/20.75] Apparent B band magnitude
71- 75 F5.2 mag Vmag [4.21/19.17] Apparent V band magnitude
77- 81 F5.2 mag Rmag [3.94/18.1] Apparent R band magnitude
83- 87 F5.2 mag Ymag [3.59/15.77] Apparent Y band magnitude
89- 93 F5.2 mag Jmag [3.4/15.23] Apparent J band magnitude
95- 99 F5.2 mag Hmag [3.17/14.73] Apparent H band magnitude
101-105 F5.2 km/s vsini [0.05/14.95] Median rotation velocity, v*sin(i),
from empirical distribution
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- TOI [0/1983]? TESS object-of-interest identifier
6- 11 F6.2 m/s sig(RV-opt) [0.37/211.32] Precision in optical radial
velocities
13- 17 F5.2 m/s sig(RV-NIR) [0.48/67.2] Precision in NIR radial
velocities
19- 23 F5.2 m/s sig(act) [0/19.07] RMS noise from stellar activity
25- 29 F5.2 m/s sig(pl) [0/12.08] RMS noise from additional planets
31- 36 F6.2 m/s sig(eff-opt) [0.46/212.09] Effective precision derived in
the optical
38- 42 F5.2 m/s sig(eff-NIR) [0.61/67.21] Effective precision derived in
the NIR
44- 56 F13.1 --- N(RV-opt) [10.1/51584355246.2] Number of optical radial
velocities (1)
58- 69 F12.1 --- N(RV-NIR) [10.1/1234463437.1] Number of NIR radial
velocities (1)
71- 82 F12.1 --- N(Obs-opt) [0.2/1228198934.4] Number of nights of
optical observations (1)
84- 93 F10.1 --- N(Obs-NIR) [0.2/29391986.6] Number of nights of NIR
observations (1)
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Note (1): The resulting number of RV measurements and total observing times
reported here are computed in the general case of RVs in the presence of
correlated noise (see Sect. 2.1.2).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 11-Feb-2019