J/ApJ/899/29 Radial velocities of TOI-1728 with HPF (Kanodia+, 2020)
TOI-1728b: The Habitable-zone Planet Finder Confirms a Warm Super-Neptune
Orbiting an M-dwarf Host.
Kanodia S., Canas C.I., Stefansson G., Ninan J.P., Hebb L., Lin A.S.J.,
Baran H., Maney M., Terrien R.C., Mahadevan S., Cochran W.D., Endl M.,
Dong J., Bender C.F., Diddams S.A., Ford E.B., Fredrick C., Halverson S.,
Hearty F., Metcalf A.J., Monson A., Ramsey L.W., Robertson P., Roy A.,
Schwab C., Wright J.T.
<Astrophys. J., 899, 29 (2020)>
=2020ApJ...899...29K 2020ApJ...899...29K
ADC_Keywords: Exoplanets; Stars, M-type; Stars, dwarfs; Photometry, RI;
Radial velocities
Keywords: Exoplanet detection methods ; Radial velocity ; Planet hosting stars
Abstract:
We confirm the planetary nature of TOI-1728b using a combination of
ground-based photometry, near-infrared Doppler velocimetry and
spectroscopy with the Habitable-zone Planet Finder. TOI-1728 is an
old, inactive M0 star with Teff=3980-32+31K, which hosts a
transiting super-Neptune at an orbital period of ∼3.49days. Joint
fitting of the radial velocities and TESS and ground-based transits
yields a planetary radius of 5.05-0.17+0.16 R⊕, mass
26.78-5.13+5.43M⊕, and eccentricity 0.057-0.039+0.054.
We estimate the stellar properties, and perform a search for He
10830Å absorption during the transit of this planet and claim a
null detection with an upper limit of 1.1% with 90% confidence. A
deeper level of He 10830Å absorption has been detected in the
planet atmosphere of GJ3470b, a comparable gaseous planet. TOI-1728b
is the largest super-Neptune-the intermediate subclass of planets
between Neptune and the more massive gas-giant planets-discovered
around an M-dwarf. With its relatively large mass and radius, TOI-1728
represents a valuable data point in the M-dwarf exoplanet mass-radius
diagram, bridging the gap between the lighter Neptune-sized planets
and the heavier Jovian planets known to orbit M dwarfs. With a low
bulk density of 1.14-0.24+0.26g/cm3, and orbiting a bright host
star (J∼9.6, V∼12.4), TOI-1728b is also a promising candidate for
transmission spectroscopy both from the ground and from space, which
can be used to constrain planet formation and evolutionary models.
Description:
TOI-1728 was observed by Transiting Exoplanet Survey Satellite (TESS)
in Sector 20 from 2019 December 24 to 2020 January 19 at two-minute
cadence.
We observed a transit of TOI-1728b on the night of 2020 February 22
using the Richard S. Perkin telescope on the campus of Hobart and
William Smith Colleges (Geneva, New York, United States). The 0.43m
(17") f/6.8 Planewave Corrected Dall-Kirkham (CDK) telescope rests on
a Paramount equatorial mount with an SBIG8300M camera mounted at
Cassegrain focus. The camera detector has an array of 3326x2504,
5.4µm pixels resulting in a ∼21x16' field of view. We obtained a
series of 92 consecutive images over 5hr centered on the target in 1x1
binning mode in the Sloan r' filter.
We observed a transit of TOI-1728b on the night of 2020 February 22
using the 0.6m telescope located on the roof of the Penn State Davey
Laboratory (University Park, Pennsylvania, United States). The
telescope was installed in 2014 and has an Apogee/Andor Aspen CG42
camera, using a CCD42-10 2048x2048 pixel chip from e2v with 13.5micron
pixels. This results in a plate scale of ∼0.77 per pixel and a field
of view of 24'x24'. The observations were made with the Johnson I
filter and an engineered diffuser, with an exposure time of 45s.
We observed TOI-1728 using Habitable Planet Finder (HPF), a
high-resolution (R∼55000), NIR (8080-12780Å) precision RVel
spectrograph located at the 10meter Hobby-Eberly Telescope (HET) in
Texas.
Objects:
--------------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
--------------------------------------------------------------------
08 02 26.55 +64 47 48.9 TOI-1728 = UCAC4 774-029023 (P=3.49d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 33 30 RVs of TOI-1728
fig9.dat 73 45008 Posteriors from dynamic nested sampling from juliet
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See also:
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
J/A+A/624/A49 : Spectra Earth-like planets around M-dwarfs (Wunderlich+, 2019)
J/AJ/157/113 : TESS M-dwarf exoplanetary systems (Ballard, 2019)
J/ApJ/887/261 : Compilation planets around M dwarfs (Martinez-Rodriguez+, 2019)
J/AJ/159/100 : Flux & RVs of the dwarf G9-40 with K2 & HPF (Stefansson+, 2020)
J/AJ/160/192 : Photometry and RVs of K2-25b with HPF (Stefansson+, 2020)
J/AJ/160/259 : HPF RVs and TESS photometry of TOI-1266 (Stefansson+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [0/35] Observation sequence number
4- 16 F13.5 d BJD [2458907/2458960] Barycentric Julian Date
18- 23 F6.2 m/s RVel [-38.93/42.74] Radial Velocity
25- 29 F5.2 m/s e_RVel [7.34/32.39] Uncertainty in RVel
31- 33 I3 --- SNR [42/175] Signal-to-noise ratio
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Byte-by-byte Description of file: fig9.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq [0/45007] Sequential running number
7- 13 F7.5 d Per [3.4912/3.4918] Orbital Period
15- 21 F7.5 --- Rp/R* [0.06/0.09] Scaled Radius
23- 30 F8.5 --- a/R* [12.6/14.3] Scaled Semi-major axis
32- 38 F7.5 --- b [0.0003/0.75] Impact Parameter
40- 47 F8.5 --- ecoso [-0.61/0.52] e-omega parameterization,
sqrt(e)*cosine(ω)
49- 56 F8.5 --- esino [-0.53/0.41] e-omega parameterization,
sqrt(e)*sine(ω)
58- 64 F7.5 --- D-TESS [0.067/1] Dilution due to presence of background
stars in TESS aperture
66- 73 F8.5 m/s K [0.49/35.5] RVel semi-amplitude
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 12-Oct-2021