J/MNRAS/523/3090 HD 15906 CHEOPS PIPE and WASP lightcurves (Tuson+, 2023)
TESS and CHEOPS discover two warm sub-Neptunes transiting the bright K-dwarf
HD 15906.
Tuson A., Queloz D., Osborn H.P., Wilson T.G., Hooton M.J., Beck M.,
Lendl M., Olofsson G., Fortier A., Bonfanti A., Brandeker A., Buchhave L.A.,
Collier Cameron A., Ciardi D.R., Collins K.A., Gandolfi D., Garai Z.,
Giacalone S., Gomes da Silva J., Howell S.B., Patel J.A., Persson C.M.,
Serrano L.M., Sousa S.G., Ulmer-Moll S., Vanderburg A., Ziegler C.,
Alibert Y., Alonso R., Anglada G., Barczy T., Barrado Navascues D.,
Barros S.C.C., Baumjohann W., Beck T., Benz W., Billot N., Bonfils X.,
Borsato L., Broeg C., Cabrera J., Charnoz S., Conti D.M., Csizmadia Sz.,
Cubillos P.E., Davies M.B., Deleuil M., Delrez L., Demangeon O.D.S.,
Demory B.-O., Dragomir D., Dressing C.D., Ehrenreich D., Erikson A.,
Essack Z., Farinato J., Fossati L., Fridlund M., Furlan E., Gill H.,
Gillon M., Gnilka C.L., Gonzales E., Gudel M., Gunther M.N., Hoyer S.,
Isaak K.G., Jenkins J.M., Kiss L.L., Laskar J., Latham D.W., Law N.,
Lecavelier des Etangs A., Lo Curto G., Lovis C., Luque R., Magrin D.,
Mann A.W., Maxted P.F.L., Mayor M., McDermott S., Mecina M., Mordasini C.,
Mortier A., Nascimbeni V., Ottensamer R., Pagano I., Palle E., Peter G.,
Piotto G., Pollacco D., Pritchard T., Ragazzoni R., Rando N., Ratti F.,
Rauer H., Ribas I., Ricker G.R., Rieder M., Santos N.C., Savel A.B.,
Scandariato G., Schwarz R.P., Seager S., Segransan D., Shporer A.,
Simon A.E., Smith A.M.S., Steller M., Stockdale C., Szabo Gy.M.,
Thomas N., Torres G., Tronsgaard R., Udry S., Ulmer B., Van Grootel V.,
Vanderspek R., Venturini J., Walton N.A., Winn J.N., Wohler B.
<Mon. Not. R. Astron. Soc. 523, 3090-3118 (2023)>
=2023MNRAS.523.3090T 2023MNRAS.523.3090T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, K-type ; Exoplanets ; Photometry ; Optical
Keywords: techniques: photometric - planets and satellites: detection -
planets and satellites: fundamental parameters -
stars: fundamental parameters -
stars: individual: HD 15906 (TOI 461, TIC 4646810)
Abstract:
We report the discovery of two warm sub-Neptunes transiting the bright
(G=9.5mag) K-dwarf HD 15906 (TOI 461, TIC 4646810). This star was
observed by the Transiting Exoplanet Survey Satellite (TESS) in
sectors 4 and 31, revealing two small transiting planets. The inner
planet, HD 15906 b, was detected with an unambiguous period but the
outer planet, HD 15906 c, showed only two transits separated by
∼734 days, leading to 36 possible values of its period. We performed
follow-up observations with the CHaracterising ExOPlanet Satellite
(CHEOPS) to confirm the true period of HD 15906 c and improve the
radius precision of the two planets. From TESS, CHEOPS and additional
ground-based photometry, we find that HD 15906 b has a radius of
2.24±0.08 R⊕ and a period of 10.924709±0.000032 days,
whilst HD 15906 c has a radius of 2.93+0.07-0.06R⊕ and a
period of 21.583298+0.000052-0.000055 days. Assuming zero bond
albedo and full day-night heat redistribution, the inner and outer
planet have equilibrium temperatures of 668±13K and 532±10K,
respectively. The HD 15906 system has become one of only six
multiplanet systems with two warm (≲700K) sub-Neptune sized planets
transiting a bright star (G≥10mag). It is an excellent target for
detailed characterisation studies to constrain the composition of
sub-Neptune planets and test theories of planet formation and
evolution.
Description:
We present the CHEOPS and WASP photometry of HD 15906. We include the
raw and detrended PIPE lightcurves for all 6 CHEOPS visits, where
visit 5 includes a transit of planet b and visits 3 and 6 include a
transit of planet c. We also include the ground-based WASP lightcurve.
Objects:
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RA (2000) DE Designation(s)
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02 33 05.28 -10 21 06.4 HD 15906 = TOI 461 = TIC 4646810
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
detrlc01.dat 60 304 CHEOPS visit 1 detrended PIPE data.
(File key CHPR110048TG005901_V0200)
detrlc02.dat 60 325 CHEOPS visit 2 detrended PIPE data.
(File key CHPR110048TG006201_V0200)
detrlc03.dat 60 320 CHEOPS visit 3 detrended PIPE data.
(File key CHPR110048TG005301_V0200)
detrlc04.dat 60 306 CHEOPS visit 4 detrended PIPE data.
(File key CHPR110048TG005101_V0200)
detrlc05.dat 60 433 CHEOPS visit 5 detrended PIPE data.
(File key CHPR110048TG009901_V0200)
detrlc06.dat 60 344 CHEOPS visit 6 detrended PIPE data.
(File key CHPR110048TG009801_V0200)
pipelc01.dat 143 346 CHEOPS visit 1 raw PIPE data.
(File key CHPR110048TG005901_V0200)
pipelc02.dat 143 358 CHEOPS visit 2 raw PIPE data.
(File key CHPR110048TG006201_V0200)
pipelc03.dat 143 356 CHEOPS visit 3 raw PIPE data.
(File key CHPR110048TG005301_V0200)
pipelc04.dat 143 353 CHEOPS visit 4 raw PIPE data.
(File key CHPR110048TG005101_V0200)
pipelc05.dat 143 476 CHEOPS visit 5 raw PIPE data.
(File key CHPR110048TG009901_V0200)
pipelc06.dat 143 375 CHEOPS visit 6 raw PIPE data.
(File key CHPR110048TG009801_V0200)
wasp_lc.dat 67 38740 Ground-based WASP data
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Byte-by-byte Description of file: detrlc0?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.13 d Time Barycentric Julian Date (BJD-2457000)
20- 37 F18.16 --- Flux Normalised flux (detrended)
39- 60 F22.20 --- e_Flux Normalised flux (detrended) error
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Byte-by-byte Description of file: pipelc0?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.13 d Time Barycentric Julian Date (BJD-2457000)
20- 37 F18.16 --- Flux Normalised flux
39- 60 F22.20 --- e_Flux Normalised flux error
62- 81 F20.16 deg Roll CHEOPS spacecraft roll angle
83-102 F20.14 e-/pix bg Background flux
104-121 F18.14 pix xc x-coordinate relative to corner of subarray
123-140 F18.14 pix yc y-coordinate relative to corner of subarray
142-143 I2 --- Flag Data quality flag (1)
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Note (1): PIPE data quality flag = integer sum of the following indicators:
0 = no recognised issue with data point
1 = deviating centroid (far off the median centroid)
2 = abnormally high level of masked pixels in frame
(e.g., satellite crossing or a cosmic ray hit)
4 = strongly deviating flux in frame
(e.g., strong background or satellite crossing)
8 = source not found in subarray
16 = strongly deviating background flux in frame
(e.g., pointing is close to Earth limb)
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Byte-by-byte Description of file: wasp_lc.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 F22.16 d Time Barycentric Julian Date (BJD-2457000)
24- 43 F20.18 --- Flux Normalised flux
45- 67 E23.15 --- e_Flux Normalised flux error
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Acknowledgements:
Amy Tuson, alt59(at)cam.ac.uk
(End) Patricia Vannier [CDS] 01-Jun-2023