J/AJ/159/120 Transit time of K2-146b and K2-146c with K2 and HPF (Lam+, 2020)
It takes two planets in resonance to tango around K2-146.
Lam K.W.F., Korth J., Masuda K., Csizmadia S., Eigmuller P.,
Stefansson G.K., Endl M., Albrecht S., Robertson P., Luque R.,
Livingston J.H., Hirano T., Sobrino R.A., Barragan O., Cabrera J.,
Carleo I., Chaushev A., Cochran W.D., Dai F., de Leon J., Deeg H.J.,
Erikson A., Esposito M., Fridlund M., Fukui A., Gandolfi D., Georgieva I.,
Cuesta L.G., Grziwa S., Guenther E.W., Hatzes A.P., Hidalgo D., Hjorth M.,
Kabath P., Knudstrup E., Lund M.N., Mahadevan S., Mathur S., Rodriguez P.M.,
Murgas F., Narita N., Nespral D., Niraula P., Palle E., Patzold M.,
Persson C.M., Prieto-Arranz J., Rauer H., Redfield S., Ribas I., Skarka M.,
Smith A.M.S., Subjak J., Van Eylen V.
<Astron. J., 159, 120 (2020)>
=2020AJ....159..120L 2020AJ....159..120L
ADC_Keywords: Exoplanets; Stars, dwarfs; Spectra, infrared; Photometry; Optical
Keywords: Exoplanet astronomy ; Transit photometry ; Timing variation methods ;
Mini Neptunes ; Exoplanet systems ; Photometry ;
Astrometric exoplanet detection ; Transit timing variation method
Abstract:
K2-146 is a cool, 0.358M☉ dwarf that was found to host a
mini-Neptune with a 2.67day period. The planet exhibited strong
transit timing variations (TTVs) of greater than 30minutes, indicative
of the presence of an additional object in the system. Here we report
the discovery of the previously undetected outer planet in the system,
K2-146c, using additional photometric data. K2-146c was found to have
a grazing transit geometry and a 3.97day period. The outer planet was
only significantly detected in the latter K2 campaigns presumably
because of precession of its orbital plane. The TTVs of K2-146b and c
were measured using observations spanning a baseline of almost
1200days. We found strong anti-correlation in the TTVs, suggesting the
two planets are gravitationally interacting. Our TTV and transit model
analyses revealed that K2-146b has a radius of 2.25±0.10R{earth}
and a mass of 5.6±0.7M{earth}, whereas K2-146c has a radius of
2.59-0.39+1.81R_{earth} and a mass of 7.1±0.9M{earth}. The
inner and outer planets likely have moderate eccentricities of
e=0.14±0.07 and 0.16±0.07, respectively. Long-term numerical
integrations of the two-planet orbital solution show that it can be
dynamically stable for at least 2Myr. We show that the resonance
angles of the planet pair are librating, which may be an indication
that K2-146b and c are in a 3:2 mean motion resonance. The orbital
architecture of the system points to a possible convergent migration
origin.
Description :
The K2 photometric observations were obtained between 2015 April 27
and 2018 July 2, spanning a baseline of almost 1200 days. The K2
target pixel data were downloaded from the Mikulski Archive for Space
Telescope (MAST).
We obtained spectra with the Habitable-zone Planet Finder (HPF)
between 2019 February 22 and 2019 May 9. HPF is a high-resolution
(R=55000) precision-fiber-fed, near-infrared (NIR) spectrograph
recently installed on the Hobby-Eberly Telescope, covering the
information-rich z, Y, and J bands (810-1280 nm).
The methods used to extract the transit times is describe in section 4
of the article.
Objects:
-------------------------------------------------------------
RA (2000) DE Designation(s)
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08 40 06.42 +19 05 34.4 K2-146b = EPIC 211924657.01
08 40 06.42 +19 05 34.4 K2-146c = K2-146c
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
figb3.dat 26 71 Individual transits of K2-146b
figb4.dat 25 28 Individual transits of K2-146c
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/496/521 : Radial velocities of HD45364 (Correia+, 2009)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/ApJS/197/8 : Kepler's candidate transiting planets (Lissauer+, 2011)
J/ApJS/200/15 : HARPS-TERRA project. I. (Anglada-Escude+, 2012)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/ApJ/767/95 : Improved parameters of smallest KIC stars (Dressing+, 2013)
J/ApJ/790/146 : Planets in Kepler's transiting systems (Fabrycky+, 2014)
J/A+A/582/A33 : K2-19b light curve (Armstrong+, 2015)
J/ApJ/807/45 : Potentially habitable planets around dwarfs (Dressing+,2015)
J/MNRAS/463/1780 : Exoplanet candidates in Praesepe (M 44) (Libralato+, 2016)
J/AJ/154/207 : K2 systems orbiting low-mass stars (Dressing+, 2017)
J/AJ/154/64 : Transit times of Kepler-448b and Kepler-693b (Masuda, 2017)
J/A+A/601/A128 : K2-19b and K2-19c radial velocity curves (Nespral+, 2017)
J/ApJ/836/77 : Library of high-S/N opt. spectra of FGKM stars (Yee+, 2017)
J/AJ/156/277 : 60 validated planets K2 campaigns 5-8 (Livingston+, 2018)
J/AJ/155/48 : California-Kepler Survey. V. Masses and radii (Weiss+, 2018)
J/A+A/628/A39 : Radial velocities of GJ 357 (Luque+, 2019)
Byte-by-byte Description of file: figb3.dat
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Bytes Format Units Label Explanations
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1- 11 F11.3 d Time [2457142/2458301] Barycentric Julian Date of transit
13- 22 F10.8 d e_Time [0.001/0.006] Uncertainty in Time
24- 26 I3 --- Num [0/437] Transit number
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Byte-by-byte Description of file: figb4.dat
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Bytes Format Units Label Explanations
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1- 11 F11.3 d Time [2458096/2458300] Barycentric Julian Date of transit
13- 22 F10.8 d e_Time [0.002/0.008] Uncertainty in Time
24- 25 I2 --- Num [0/51] Transit number
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 22-Oct-2020