J/MNRAS/492/1761 TOI-222: a 34-d eclipsing binary (Lendl+, 2020)
TOI-222: a single-transit TESS candidate revealed to be a 34-d eclipsing binary
with CORALIE, EulerCam, and NGTS.
Lendl M., Bouchy F., Gill S., Nielsen L.D., Turner O., Stassun K.,
Acton J.S., Anderson D.R., Armstrong D.J., Bayliss D., Belardi C.,
Bryant E.M., Burleigh M.R., Chaushev A., Casewell S.L., Cooke B.F.,
Eigmuller P., Gillen E., Goad M.R., Gunther M.N., Hagelberg J.,
Jenkins J.S., Louden T., Marmier M., Mccormac J., Moyano M., Pollacco D.,
Raynard L., Tilbrook R.H., Udry S., Vines J.I., West R.G., Wheatley P.J.,
Ricker G., Vanderspek R., Latham D.W., Seager S., Winn J., Jenkins J.M.,
Addison B., Briceno C., Brahm R., Caldwell D.A., Doty J., Espinoza N.,
Goeke B., Henning T., Jordan A., Krishnamurthy A., Law N., Morris R.,
Okumura J., Mann A.W., Rodriguez J.E., Sarkis P., Schlieder J.,
Twicken J.D., Villanueva S., Wittenmyer R.A., Wright D.J., Ziegler C.
<Mon. Not. R. Astron. Soc., 492, 1761-1769 (2020)>
=2020MNRAS.492.1761L 2020MNRAS.492.1761L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Binaries, orbits ;
Radial velocities ; Effective temperatures ; Magnitudes ;
Stars, masses ; Stars, diameters ; Stars, distances ;
Proper motions ; Spectra, optical ; Photometry
Keywords: techniques: photometric - stars: individual: TOI-222 -
planetary systems
Abstract:
We report the period, eccentricity, and mass determination for the
Transiting Exoplanet Survey Satellite (TESS) single-transit event
candidate TOI-222, which displayed a single 3000ppm transit in the
TESS 2-min cadence data from Sector 2. We determine the orbital period
via radial velocity measurements (P=33.9d), which allowed for
ground-based photometric detection of two subsequent transits. Our
data show that the companion to TOI-222 is a low-mass star, with a
radius of 0.18-0.10+0.39R☉ and a mass of
0.23±0.01M☉. This discovery showcases the ability to
efficiently discover long-period systems from TESS single-transit
events using a combination of radial velocity monitoring coupled with
high-precision ground-based photometry.
Description:
The V=9.3 star HD 224286 (TIC 144440290) was observed by TESS in
Sector 2 throughout 27.4d. A single, approximately 3.5mmag deep,
transit event was identified and denominated TOI-222 by the TESS team.
TOI-222 was observed with the CORALIE spectrograph on the Swiss 1.2m
Euler telescope at La Silla Observatory, Chile (Queloz et al.
2001Msngr.105....1Q 2001Msngr.105....1Q) between 2019 January 2 and June 30. CORALIE has a
resolving power of R∼60000 and is fed by two fibres. The resulting
velocities are given in Table 1.
We then scheduled photometric observations with EulerCam, installed at
the 1.2m Euler telescope, with the goal of detecting a second transit
of the low-mass companion in front of its host. The observations were
carried out throughout 2.8h on 2019 June 13, covering approximately 75
per cent of the predicted 1σ transit window. We used an Cousins
I filter, 20s exposures and applied a large defocus to avoid
saturating the target while keeping a reasonable observation
efficiency. The EulerCam data set is presented in Table 2.
we scheduled NGTS observations to cover the next primary eclipse of
TOI-222, occurring on 2019 July 17. In total, 10 telescopes were used
to simultaneously observe the primary eclipse, collecting over 10000
individual data points with an exposure time of 10s each. The NGTS
data is given in Table 3.
The RV variation of TOI-222 was also monitored using the FEROS
spectrograph (R=48000; Kaufer et al. 1999Msngr..95....8K 1999Msngr..95....8K) mounted on
the MPG 2.2m telescope installed in La Silla Observatory. A total
number of seven spectra were obtained between 2019 June 4 and July 13.
We also obtained an additional four data points with CORALIE under
Chilean time.
A total of 60 spectra of TOI-222 were obtained at 15 epochs between
2019 May 11 and July 18, using the MINERVA-Australis telescope array
at Mt. Kent Observatory in Queensland, Australia (Wittenmyer et al.
2018AAS...23112801W 2018AAS...23112801W; Addison et al. 2019PASP..131k5003A 2019PASP..131k5003A). All of the
telescopes in the MINERVA-Australis array simultaneously feed a single
Kiwispec R4-100 high-resolution (R 80000) spectrograph with wavelength
coverage from 500 to 630nm over 26 echelle orders.
Objects:
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RA (ICRS) DE Designation(s)
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23 56 38.76 -44 43 08.6 TOI-222 = 2MASS J23563876-4443086 = CD-45 15182
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 58 83 Radial velocities for TOI-222
table2.dat 64 273 EulerCam photometry
table3.dat 32 189 NGTS photometry, binned into 2-min intervals
table4.dat 319 1 Stellar properties of the primary
table5.dat 357 1 Properties of the TOI-222 system from a global
MCMC analysis
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See also:
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/322 : UCAC4 Catalogue (Zacharias+, 2012)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD Barycentric Julian Date (BJD-2450000)
13- 20 F8.5 km/s RV Radial velocity
22- 28 F7.5 km/s e_RV Error on RV
30- 36 F7.5 km/s FWHM ? Full-Width at Half-Maximum
38- 45 F8.5 km/s BIS ? Bisector span
47- 58 A12 --- Inst Instrument used
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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- 11 F11.6 d BJD Barycentric Julian Date (BJD-2450000)
13- 20 F8.6 --- Flux Relative flux
22- 29 F8.6 --- e_Flux Error on Flux
31- 35 F5.2 pix xshift Pixel shift in x-direction
37- 41 F5.2 pix yshift Pixel shift in y-direction
43- 46 F4.2 --- Airmass Airmass
48- 52 F5.2 pix FWHM Full-Width at Half-Maximum
54- 58 F5.2 --- skyflux Sky background flux
60- 64 F5.2 s ExpTime Exposure time
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d BJD Barycentric Julian Date
16- 23 F8.6 --- Flux Relative flux
25- 32 F8.6 --- e_Flux Error on Flux
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 24 F5.2 arcsec DEs Declination (J2000)
26- 48 A23 --- Name Star name from 2MASS (Skrutskie et al.
2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233)
50- 56 F7.3 mas/yr pmRA Proper motion in right ascension from UCAC4
(Zacharias et al. 2013AJ....145...44Z 2013AJ....145...44Z,
Cat. I/322)
58- 62 F5.3 mas/yr e_pmRA Error on pmRA
64- 70 F7.3 mas/yr pmDE Proper motion in declination from UCAC4
(Zacharias et al. 2013AJ....145...44Z 2013AJ....145...44Z,
Cat. I/322)
72- 76 F5.3 mas/yr e_pmDE Error on pmDE
78- 82 F5.3 mag Vmag APASS V-band magnitude (Henden & Munari
2014CoSka..43..518H 2014CoSka..43..518H)
84- 87 F4.2 mag e_Vmag Error on Vmag
89- 94 F6.3 mag Bmag APASS B-band magnitude (Henden & Munari
2014CoSka..43..518H 2014CoSka..43..518H)
96-100 F5.3 mag e_Bmag Error on Bmag
102-106 F5.3 mag gmag APASS g-band magnitude (Henden & Munari
2014CoSka..43..518H 2014CoSka..43..518H)
108-111 F4.2 mag e_gmag Error on gmag
113-117 F5.3 mag rmag APASS r-band magnitude (Henden & Munari
2014CoSka..43..518H 2014CoSka..43..518H)
119-123 F5.3 mag e_rmag Error on rmag
125-129 F5.3 mag imag APASS i-band magnitude (Henden & Munari
2014CoSka..43..518H 2014CoSka..43..518H)
131-135 F5.3 mag e_imag Error on imag
137-143 F7.5 mag Gmag Gaia G-band magnitude (Gaia Collaboration et
al. 2016A&A...595A...2G 2016A&A...595A...2G, Cat. I/337)
145-151 F7.5 mag e_Gmag Error on Gmag
153-157 F5.3 mag Tmag TESS T-band magnitude
159-163 F5.3 mag e_Tmag Error on Tmag
165-169 F5.3 mag Jmag 2MASS J-band magnitude (Skrutskie et al.
2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233)
171-175 F5.3 mag e_Jmag Error on Jmag
177-181 F5.3 mag Hmag 2MASS H-band magnitude (Skrutskie et al.
2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233)
183-187 F5.3 mag e_Hmag Error on Hmag
189-194 F6.4 mag Kmag 2MASS K-band magnitude (Skrutskie et al.
2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233)
196-200 F5.3 mag e_Kmag Error on Kmag
202-206 F5.3 mag W1mag WISE W1 (3.4um) band magnitude (Wright et al.
2010AJ....140.1868W 2010AJ....140.1868W)
208-212 F5.3 mag e_W1mag Error on W1mag
214-218 F5.3 mag W2mag WISE W2 (4.6um) band magnitude (Wright et al.
2010AJ....140.1868W 2010AJ....140.1868W)
220-224 F5.3 mag e_W2mag Error on W2mag
226-229 I4 K Teff Effective temperature (1)
231-232 I2 K e_Teff Error on Teff (1)
234-237 F4.2 [-] [M/H] Metallicity (1)
239-242 F4.2 [-] e_[M/H] Error on [M/H] (1)
244-247 F4.2 km/s vsini Line of sight velocity (1)
249-252 F4.2 km/s e_vsini Error on vsini (1)
254-261 F8.5 km/s RV Radial velocity (1)
263-267 F5.3 km/s e_RV Error on RV (1)
269-271 F3.1 [cm/s2] logg Surface gravity (1)
273-276 F4.2 [cm/s2] e_logg Error on logg (1)
278-282 F5.3 Rsun Rad Radius from SED fit
284-288 F5.3 Rsun e_Rad Error on Rad
290-293 F4.2 Msun Mass Mass interpolated from Torres et al.
(2010A&ARv..18...67T 2010A&ARv..18...67T,
Cat. J/other/A+ARv/18.67)
295-298 F4.2 Msun e_Mass Error on Mass
300-303 F4.2 Sun rho Density
305-308 F4.2 Sun e_rho Error on rho
310-311 I2 pc Dist Distance from Bailer-Jones et al.
(2018AJ....156...58B 2018AJ....156...58B, Cat. I/347)
313-315 F3.1 pc E_Dist Upper error on Dist
317-319 F3.1 pc e_Dist Lower error on Dist
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Note (1): Values derived from CORALIE spectra
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.4 d BJD Barycentric Julian Date (BJD-2450000)
11- 16 F6.4 d E_BJD Upper error on BJD
18- 23 F6.4 d e_BJD Lower error on BJD
25- 28 F4.2 --- R1/R2 Radius ratio
30- 33 F4.2 --- E_R1/R2 Upper error on R1/R2
35- 38 F4.2 --- e_R1/R2 Lower error on R1/R2
40- 43 F4.1 deg i Inclination
45- 48 F4.2 deg E_i Upper error on i
50- 53 F4.2 deg e_i Lower error on i
55- 58 F4.1 --- a/R1 a/R1 ratio
60- 62 F3.1 --- E_a/R1 Upper error on a/R1
64- 66 F3.1 --- e_a/R1 Lower error on a/R1
68- 75 F8.5 d Period Orbital period
77- 83 F7.5 d E_Period Upper error on Period
85- 91 F7.5 d e_Period Lower error on Period
93- 98 F6.4 --- esinw sqrt(e)sinw component of eccentricity
100-105 F6.4 --- E_esinw Upper error on esinw
107-112 F6.4 --- e_esinw Lower error on esinw
114-119 F6.4 --- ecosw sqrt(e)cosw component of eccentricity
121-126 F6.4 --- E_ecosw Upper error on ecosw
128-133 F6.4 --- e_ecosw Lower error on ecosw
135-140 F6.3 km/s K Radial velocity amplitude
142-146 F5.3 km/s e_K Error on K
148-152 F5.3 Rsun R1 Radius of primary star
154-158 F5.3 Rsun e_R1 Error on R1
160-163 F4.2 Msun M1 Mass of primary star
165-168 F4.2 Msun e_M1 Error on M1
170-173 F4.2 Rsun R2 Radius of secondary star
175-178 F4.2 Rsun E_R2 Upper error on R2
180-183 F4.2 Rsun e_R2 Lower error on R2
185-188 F4.2 Msun M2 Mass of secondary star
190-193 F4.2 Msun e_M2 Error on M2
195-199 F5.3 AU a Orbital semimajor axis
201-205 F5.3 AU E_a Upper error on a
207-211 F5.3 AU e_a Lower error on a
213-216 F4.2 --- b Primary eclipse impact parameter
218-221 F4.2 --- E_b Upper error on b
223-226 F4.2 --- e_b Lower error on b
228-233 F6.4 --- e Orbital eccentricity
235-241 F7.5 --- E_e Upper error on e
243-249 F7.5 --- e_e Lower error on e
251-255 F5.2 deg w Argument of periastron
257-260 F4.2 deg E_w Upper error on w
262-265 F4.2 deg e_w Lower error on w
267-272 F6.4 --- u1TESS Quadratic limb-darkening u1 parameter for
TESS
274-279 F6.4 --- u2TESS Quadratic limb-darkening u2 parameter for
TESS
281-286 F6.4 --- u1IC Quadratic limb-darkening u1 parameter for IC
288-293 F6.4 --- u2IC Quadratic limb-darkening u2 parameter for IC
295-300 F6.4 --- u1NGTS Quadratic limb-darkening u1 parameter for
NGTS
302-307 F6.4 --- u2NGTS Quadratic limb-darkening u2 parameter for
NGTS
309-311 I3 m/s RVzpC Radial velocity zero point offset for
CORALIE (CERES) (1)
313-315 I3 m/s e_RVzpC Error on RVzpC
317-318 I2 m/s RVzpF Radial velocity zero point offset for
FEROS (1)
320-322 I3 m/s e_RVzpF Error on RVzpF
324-327 I4 m/s RVzpM3 Radial velocity zero point offset for
MINERVA3 (1)
329-331 I3 m/s e_RVzpM3 Error on RVzpM3
333-336 I4 m/s RVzpM4 Radial velocity zero point offset for
MINERVA4 (1)
338-340 I3 m/s e_RVzpM4 Error on RVzpM4
342-344 I3 m/s RVzpM5 Radial velocity zero point offset for
MINERVA5 (1)
346-348 I3 m/s e_RVzpM5 Error on RVzpM5
350-353 I4 m/s RVzpM6 Radial velocity zero point offset for
MINERVA6 (1)
355-357 I3 m/s e_RVzpM6 Error on RVzpM6
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Note (1): Radial velocity zero-point offsets relative to CORALIE
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 15-Mar-2023