Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra
(2018) In Astrophysical Journal Letters 860(1).- Abstract
The first detailed chemical abundance analysis of the M-dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5-1.7 μm), high-resolution (R ∼ 22,500) spectra from the SDSS Apache Point Galactic Evolution Experiment survey. We determined precise atmospheric parameters T eff = 3231 ±100 K, log g = 4.96 ±0.11 dex and chemical abundances of eight elements (C, O, Mg, Al, K, Ca, Ti, and Fe), finding Ross 128 to have near solar metallicity ([Fe/H] = +0.03 ± 0.09 dex). The derived results were obtained via spectral synthesis (1D LTE) adopting both MARCS and PHOENIX model atmospheres; stellar parameters and chemical abundances derived from the different adopted models do not show significant... (More)
The first detailed chemical abundance analysis of the M-dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5-1.7 μm), high-resolution (R ∼ 22,500) spectra from the SDSS Apache Point Galactic Evolution Experiment survey. We determined precise atmospheric parameters T eff = 3231 ±100 K, log g = 4.96 ±0.11 dex and chemical abundances of eight elements (C, O, Mg, Al, K, Ca, Ti, and Fe), finding Ross 128 to have near solar metallicity ([Fe/H] = +0.03 ± 0.09 dex). The derived results were obtained via spectral synthesis (1D LTE) adopting both MARCS and PHOENIX model atmospheres; stellar parameters and chemical abundances derived from the different adopted models do not show significant offsets. Mass-radius modeling of Ross 128b indicates that it lies below the pure-rock composition curve, suggesting that it contains a mixture of rock and iron, with the relative amounts of each set by the ratio of Fe/Mg. If Ross 128b formed with a subsolar Si abundance, and assuming the planet's composition matches that of the host star, it likely has a larger core size relative to the Earth despite this producing a planet with a Si/Mg abundance ratio ∼34% greater than the Sun. The derived planetary parameters - insolation flux (S Earth = 1.79 ±0.26) and equilibrium temperature (T eq = 294 ±10 K) - support previous findings that Ross 128b is a temperate exoplanet in the inner edge of the habitable zone.
(Less)
- author
- organization
- publishing date
- 2018-06-10
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- infrared: stars, planetary systems, planetstar interactions, stars: abundances, stars: fundamental parameters, stars: low-mass
- in
- Astrophysical Journal Letters
- volume
- 860
- issue
- 1
- article number
- L15
- publisher
- IOP Publishing
- external identifiers
-
- scopus:85049052764
- ISSN
- 2041-8205
- DOI
- 10.3847/2041-8213/aac896
- language
- English
- LU publication?
- yes
- id
- 3dd418b8-3c98-43ec-b20d-98f68ee92167
- date added to LUP
- 2018-07-06 12:36:12
- date last changed
- 2024-04-15 09:06:09
@article{3dd418b8-3c98-43ec-b20d-98f68ee92167, abstract = {{<p>The first detailed chemical abundance analysis of the M-dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5-1.7 μm), high-resolution (R ∼ 22,500) spectra from the SDSS Apache Point Galactic Evolution Experiment survey. We determined precise atmospheric parameters T <sub>eff</sub> = 3231 ±100 K, log g = 4.96 ±0.11 dex and chemical abundances of eight elements (C, O, Mg, Al, K, Ca, Ti, and Fe), finding Ross 128 to have near solar metallicity ([Fe/H] = +0.03 ± 0.09 dex). The derived results were obtained via spectral synthesis (1D LTE) adopting both MARCS and PHOENIX model atmospheres; stellar parameters and chemical abundances derived from the different adopted models do not show significant offsets. Mass-radius modeling of Ross 128b indicates that it lies below the pure-rock composition curve, suggesting that it contains a mixture of rock and iron, with the relative amounts of each set by the ratio of Fe/Mg. If Ross 128b formed with a subsolar Si abundance, and assuming the planet's composition matches that of the host star, it likely has a larger core size relative to the Earth despite this producing a planet with a Si/Mg abundance ratio ∼34% greater than the Sun. The derived planetary parameters - insolation flux (S <sub>Earth</sub> = 1.79 ±0.26) and equilibrium temperature (T <sub>eq</sub> = 294 ±10 K) - support previous findings that Ross 128b is a temperate exoplanet in the inner edge of the habitable zone.</p>}}, author = {{Souto, Diogo and Unterborn, Cayman T. and Smith, Verne V. and Cunha, Katia and Teske, Johanna and Covey, Kevin and Rojas-Ayala, Bárbara and García-Hernández, D. A. and Stassun, Keivan and Zamora, Olga and Masseron, Thomas and Johnson, J. A. and Majewski, Steven R. and Jönsson, Henrik and Gilhool, Steven and Blake, Cullen and Santana, Felipe}}, issn = {{2041-8205}}, keywords = {{infrared: stars; planetary systems; planetstar interactions; stars: abundances; stars: fundamental parameters; stars: low-mass}}, language = {{eng}}, month = {{06}}, number = {{1}}, publisher = {{IOP Publishing}}, series = {{Astrophysical Journal Letters}}, title = {{Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra}}, url = {{http://dx.doi.org/10.3847/2041-8213/aac896}}, doi = {{10.3847/2041-8213/aac896}}, volume = {{860}}, year = {{2018}}, }