J/AJ/166/49 BD+29 2654 equivalent Widths and line abundances (Dai+, 2023)
A Mini-Neptune Orbiting the Metal-poor K Dwarf BD+29 2654.
Dai F., Schlaufman K.C., Reggiani H., Bouma L., Howard A.W., Chontos A.,
Pidhorodetska D., Van Zandt J., Akana Murphy J.M., Rubenzahl R.A.,
Polanski A.S., Lubin J., Beard C., Giacalone S., Holcomb R., Batalha N.M.,
Crossfield I., Dressing C., Fulton B., Huber D., Isaacson H., Kane S.R.,
Petigura E.A., Robertson P., Weiss L.M., Belinski A.A., Boyle A.W.,
Burke C.J., Castro-Gonzalez A., Ciardi D.R., Daylan T., Fukui A., Gill H.,
Guerrero N.M., Hellier C., Howell S.B., Lillo-Box J., Murgas F.,
Narita N., Palle E., Rodriguez D.R., Savel A.B., Shporer A., Stassun K.G.,
Striegel S., Caldwell D.A., Jenkins J.M., Ricker G.R., Seager S.,
Vanderspek R., Winn J.N.
<Astron. J., 166, 49 (2023)>
=2023AJ....166...49D 2023AJ....166...49D
ADC_Keywords: Exoplanets; Stars, K-type; Spectra, optical
Keywords: Exoplanets ; Mini Neptunes ; Ocean planets
Abstract:
We report the discovery and Doppler mass measurement of a 7.4days
2.3R⊕ mini-Neptune around a metal-poor K-dwarf BD+29-2654
(TOI-2018). Based on a high-resolution Keck/HIRES spectrum, the Gaia
parallax, and multiwavelength photometry from the UV to the
mid-infrared, we found that the host star has Teff=4174-42+34K,
logg=4.62-0.03+0.02, [Fe/H]=-0.58±0.18,
M*=0.57±0.02M☉, and R*=0.62±0.01R☉. Precise Doppler
measurements with Keck/HIRES revealed a planetary mass of
Mp=9.2±2.1M⊕ for TOI-2018b. TOI-2018b has a mass and radius
that are consistent with an Earthlike core, with a ∼1%-by-mass
hydrogen/helium envelope or an ice-rock mixture. The mass of TOI-2018b
is close to the threshold for runaway accretion and hence giant planet
formation. Such a threshold is predicted to be around 10M⊕ or
lower for a low-metallicity (low-opacity) environment. If TOI-2018b is
a planetary core that failed to undergo runaway accretion, it may
underline the reason why giant planets are rare around low-
metallicity host stars (one possibility is their shorter disk
lifetimes). With a K-band magnitude of 7.1, TOI-2018b may be a
suitable target for transmission spectroscopy with the James Webb
Space Telescope. The system is also amenable to metastable Helium
observation; the detection of a Helium exosphere would help
distinguish between a H/He-enveloped planet and a water world.
Description:
We analyzed an archival high-resolution, high-S/N spectrum of TOI-2018
taken with the High Resolution Echelle Spectrometer on the 10m Keck
Telescope (Keck/HIRES) on 2012 July 26. The spectrum was taken without
the iodine cell and it reached an S/N of about 200per reduced pixel
near5500Å after a 600s exposure.
Objects:
-------------------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
-------------------------------------------------------------------------
15 19 21.15 +29 12 22.2 BD+29 2654 = 2MASS J15192115+2912223 (7.4d)
-------------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 40 133 Atomic data, equivalent Widths and line abundances
--------------------------------------------------------------------------------
See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
VI/39 : Model Atmospheres (Kurucz, 1979)
J/A+A/415/1153 : [Fe/H] for 98 extra-solar planet-host stars (Santos+, 2004)
J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/AJ/152/180 : Bolometric fluxes clipsing binaries Tycho-2 (Stassun+, 2016)
J/AJ/154/226 : Photometry and radial velocities of K2-131 (Dai+, 2017)
J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)
J/AJ/153/71 : Kepler follow-up observation program. I. (Furlan+, 2017)
J/ApJ/844/102 : KIC parallaxes from asteroseismology vs Gaia (Huber+, 2017)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/155/89 : California-Kepler Survey (CKS). IV. Planets (Petigura+, 2018)
J/A+A/630/A89 : WASP-12b and WASP-43b griz light curves (Parviainen+, 2019)
J/AN/341/996 : Stellar companions of (C)TOIs (Mugrauer+, 2020)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
J/MNRAS/506/150 : The GALAH+ Survey DR3 (Buder+, 2021)
J/A+A/653/A41 : L 98-59 (TOI-175) ESPRESSO observations (Demangeon+, 2021)
J/ApJS/254/39 : Exoplanet candidates from TESS 1st 2yr obs (Guerrero+, 2021)
J/AN/342/840 : Stellar companions of (C)TOIs (Mugrauer+, 2021)
J/AJ/164/215 : Candidate members of Cep-Her, RSG-5 and CH-2 (Bouma+, 2022)
J/other/Sci/377.1211 : RV and LC of 8 M dwarf stars with planets (Luque+, 2022)
J/AJ/163/159 : Species abundances in WASP-77A (Reggiani+, 2022)
J/MNRAS/511/1043 : Sub-Neptunes transiting TOI-1064 (Wilson+, 2022)
J/AJ/165/88 : Radial velocity follow up of TOI-561 b (Brinkman+, 2023)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 0.1nm Wave [4470/7934] Wavelength; Angstroms
10- 14 A5 --- Species Species identifier
16- 20 F5.3 eV ExPot [0.12/5.11] Excitation potential
22- 27 F6.3 [-] loggf [-5.34/0.5] log oscillator strength
29- 34 F6.2 10-13m EW [1.7/170] Equivalent width; milli-Angstroms
36- 40 F5.3 [-] logX [1.26/7.5] log number abundance
--------------------------------------------------------------------------------
(End) Prepared by [AAS], Coralie Fix [CDS], 09-Feb-2024