J/AJ/168/93 Phot. follow-up of TOI-2015 & discovery of TOI-2015b (Jones+, 2024)
TOI-2015 b: a warm Neptune with transit timing variations orbiting an active
mid-type M dwarf.
Jones S.E., Stefansson G., Masuda K., Libby-Roberts J.E., Gardner C.N.,
Holcomb R., Beard C., Robertson P., Canas C.I., Mahadevan S., Kanodia S.,
Lin A.S.J., Kobulnicky H.A., Parker B.A., Bender C.F., Cochran W.D.,
Diddams S.A., Fernandes R.B., Gupta A.F., Halverson S., Hawley S.L.,
Hearty F.R., Hebb L., Kowalski A., Lubin J., Monson A., Ninan J.P.,
Ramsey L., Roy A., Schwab C., Terrien R.C., Wisniewski J.
<Astron. J., 168, 93 (2024)>
=2024AJ....168...93J 2024AJ....168...93J
ADC_Keywords: Photometry, RI; Stars, double and multiple; Exoplanets;
Radial velocities; Spectra, infrared
Keywords: Exoplanets ; M dwarf stars ; Transits ; Radial velocity ;
Transit timing variation method
Abstract:
We report the discovery of a close-in (Porb=3.349days) warm Neptune
with clear transit timing variations (TTVs) orbiting the nearby
(d=47.3pc) active M4 star, TOI-2015. We characterize the planet's
properties using Transiting Exoplanet Survey Satellite (TESS)
photometry, precise near-infrared radial velocities (RVs) with the
Habitable-zone Planet Finder Spectrograph, ground-based photometry,
and high-contrast imaging. A joint photometry and RV fit yields a
radius Rp=3.37-0.20+0.15R⊕, mass
mp=16.4-4.1+4.1M⊕, and density
ρp=2.32-0.37+0.38g/cm3 for TOI-2015 b, suggesting a likely
volatile-rich planet. The young, active host star has a rotation
period of Prot=8.7±0.9days and associated rotation-based age
estimate of 1.1±0.1Gyr. Though no other transiting planets are seen
in the TESS data, the system shows clear TTVs of super-period
Psup∼430days and amplitude ∼100min. After considering multiple likely
period-ratio models, we show an outer planet candidate near a 2:1
resonance can explain the observed TTVs while offering a dynamically
stable solution. However, other possible two-planet solutions
--including 3:2 and 4:3 resonances-- cannot be conclusively excluded
without further observations. Assuming a 2:1 resonance in the joint
TTV-RV modeling suggests a mass of mb=13.3-4.5+4.7M⊕ for
TOI-2015 b and mc=6.8-2.3+3.5M⊕ for the outer candidate.
Additional transit and RV observations will be beneficial to
explicitly identify the resonance and further characterize the
properties of the system.
Description:
TESS observed TOI-2015 with a 2 minutes cadence in two sectors:
Sector 24, from 2020 April 16 to 2020 May 13, and Sector 51, from
2022 April 22 to 2022 May 18.
In the more recent seeing-limited image, we observed TOI-2015 with the
Three-hundred MilliMeter Telescope (TMMT) at Las Campanas Observatory
on 2021 May 16. We obtained the TMMT image with the Johnson I filter
and an exposure time of 120s. See Section 2.2.
We obtained speckle imaging of TOI-2015 on 2021 March 29 with the NASA
Exoplanet Star and Speckle Imager (NESSI) on the WIYN 3.5m telescope.
Additionally, we observed TOI-2015 with high-contrast adaptive optics
(AO) imaging with the ShaneAO system on the 3m Telescope at Lick
Observatory on 2021 May 27. See Section 2.3.
The Habitable-zone Planet Finder (HPF) is a NIR fiber-fed spectrograph
on the 10m HET at McDonald Observatory in Texas. HPF covers the
information-rich z, Y, and J bands (810-1280nm) with a spectral
resolution of R∼55000. In total, we retained 104 HPF spectra in over
37 HET visits with a median S/N of 46, and a baseline of 639days.
See Section 2.4.
A partial transit of TOI-2015 b was observed by the Las Cumbres
Observatory Global Telescope (LCOGT) observing team on the night of
2020 July 4 using the Sinistro imaging cameras on the 1m telescope at
its South African Astronomical Observatory site. The Bessell I filter
was used with an exposure time of 100s. See Section 2.5.1.
We obtained a full transit of TOI-2015 b on the night of 2021 July 18
with the Wyoming Infrared Observatory (WIRO) DoublePrime prime-focus
imager on the WIRO 2.3m Telescope. The images used the Sloan Digital
Sky Survey (SDSS) i' filter and an exposure time of 75s.
See Section 2.5.2.
On the night of 2023 April 23, we observed a full TOI-2015 b transit
using the Apogee Alta F16 camera on the 0.6m telescope at Red Buttes
Observatory (RBO) in Wyoming. We used the Bessell I filter and 240s
exposures. See Section 2.5.3.
We obtained a full transit of TOI-2015 b on the night of 2023 April 23
with the Astrophysical Research Consortium Telescope Imaging Camera
(ARCTIC) on the Astrophysical Research Council (ARC) 3.5m telescope at
the Apache Point Observatory.
On the night of 2023 May 3, we observed another full transit of
TOI-2015 b. We used the SDSS i' filter and 45s exposures.
See Section 2.5.4.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
15 28 31.90 +27 21 38.8 TOI-2015 = TIC 368287008
15 28 31.90 +27 21 38.8 TOI-2015b = TOI-2015.01
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table5.dat 37 110 Predicted future mid-transit times of TOI-2015b and
their uncertainties for the 2:1 solution
table6.dat 86 37 Habitable-zone Planet Finder (HPF) RVs used in this
work along with the differential line width,
chromatic index, and the line indices for the
three Ca II infrared triplet lines
fig1.dat 36 24658 Photometry of TOI-2015
--------------------------------------------------------------------------------
See also:
II/328 : AllWISE Data Release (Cutri+ 2013)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
J/ApJ/703/L99 : Outlandish orbit of HAT-P-7b (Winn+, 2009)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/ApJ/757/18 : RVs for 16 hot Jupiter host stars (Albrecht+, 2012)
J/AJ/145/102 : Sp. of bright M dwarfs in the northern sky (Lepine+, 2013)
J/A+A/564/A125 : AGN Torus model comparison of AGN in the CDFS (Buchner+, 2014)
J/AJ/147/20 : Spectroscopy of 447 nearby M dwarfs (Newton+, 2014)
J/ApJ/807/45 : Habitable planets orbiting M dwarfs (Dressing+, 2015)
J/ApJ/812/3 : MEarth mid-to-late M dwarfs rot. & kinematics (West+, 2015)
J/A+A/586/A75 : Simulations of hot gas planets atmospheres (Salz+, 2016)
J/AJ/154/64 : Transit times of Kepler-448b and Kepler-693b (Masuda, 2017)
J/AJ/153/96 : Standard Galactic field RR Lyrae. I. Phot. (Monson+, 2017)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/155/180 : A catalog of cool dwarf targets for the TESS (Muirhead+, 2018)
J/AJ/156/102 : TESS Input Catalog and Candidate Target List (Stassun+, 2018)
J/AJ/158/133 : Transit timing and light curves for K2-146 (Hamann+, 2019)
J/AJ/158/75 : Mid-type M dwarfs planet occurrences (Hardegree-Ullman+, 2019)
J/A+A/642/A115 : CARMENES input catalogue of M dwarfs. V. (Cifuentes+, 2020)
J/ApJ/899/29 : Radial velocities of TOI-1728 with HPF (Kanodia+, 2020)
J/AJ/159/120 : Transit time of K2-146b & K2-146c with K2 and HPF (Lam+, 2020)
J/AJ/159/100 : Flux & RVs of G9-40 with K2 & HPF (Stefansson+, 2020)
J/AJ/160/192 : Photometry and RVs of K2-25b with HPF (Stefansson+, 2020)
J/AJ/161/119 : The TESS-Keck survey. IV. Rvel for WASP-107 (Rubenzahl+, 2021)
J/AJ/165/33 : HIRES TOI-1136s planets and planet b RVs (Dai+, 2023)
J/AJ/165/5 : SDSS ugri photometry of HD 189733 (Gardner-Watkins+, 2023)
J/AJ/165/265 : Properties of 363 M-dwarfs from TESS (Ment+, 2023)
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 yr Obs.Y [2024/2025] Mean year of the prediction; UTC
6- 7 I2 "month" Obs.M Mean month of the prediction; UTC
9- 10 I2 d Obs.D Mean day of the prediction; UTC
12- 13 I2 h Obs.h Hour day of the prediction; UTC
15- 16 I2 min Obs.m Minute of the prediction; UTC
18- 19 I2 s Obs.s Second of the prediction; UTC
21- 31 F11.3 d BJD [2460462.92/2460827.82] Mean of Barycentric
Julian Date of TTV midpoint prediction
33- 37 F5.3 d e_BJD [0.02/0.06] Standard deviation in BJD
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d BJD [2459065.6/2459704.8] Barycentric Julian Date
15- 19 F5.1 m/s RVel [-33.2/34.3] Radial velocity
21- 24 F4.1 m/s e_RVel [8.7/36.5] Uncertainty in RVel
26- 31 F6.1 m2/s2 dLW [-160.4/281.2] Differential line width
33- 37 F5.1 m2/s2 e_dLW [23.1/100.3] Uncertainty in dLW
39- 44 F6.1 --- CRX [-485.4/555.4] Chromatic Index; m/s/Np
46- 50 F5.1 --- e_CRX [88.7/362.9] Uncertainty in CRX
52- 56 F5.3 --- CaII-RT1 [0.78/1.11]? Line number 1 Ca II infrared
triplet line index
58- 62 F5.3 --- e_CaII-RT1 [0.006/0.03]? Uncertainty in CaII-R1
64- 68 F5.3 --- CaII-RT2 [0.49/0.8] Line number 2 Ca II infrared
triplet line index
70- 74 F5.3 --- e_CaII-RT2 [0.006/0.03] Uncertainty in CaII-R2
76- 80 F5.3 --- CaII-RT3 [0.4/0.7] Line number 3 Ca II infrared
triplet line index
82- 86 F5.3 --- e_CaII-RT3 [0.005/0.03] Uncertainty in CaII-R3
--------------------------------------------------------------------------------
Byte-by-byte Description of file: fig1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 F16.8 d BJD [2458955.79/2460067.98] Barycentric Julian Date
18- 23 F6.4 --- Flux [0.96/1.05] Relative flux from Inst
25- 30 F6.4 --- e_Flux [0.0004/0.04] Uncertainty in Flux
32- 36 A5 --- Inst Instrument/Facility of photometric observation (1)
--------------------------------------------------------------------------------
Note (1): Instrument/facility as follows:
TESS = Transiting Exoplanet Survey Satellite mission (23743 occurrences)
ARC = Astrophysical Research Consortium 3.5m Telescope (622 occurrences)
WIRO = Wyoming Infrared Observatory 2.3m Telescope (117 occurrences)
RBO = Red Buttes Observatory 0.6m telescope (92 occurrences)
LCOGT = Las Cumbres Observatory Global 1m Telescope at SAAO (84 occurrences)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Nov-2024