Results 61 to 70 of about 534 (173)

Utilizing Photometry from Multiple Sources to Mitigate Stellar Variability in Precise Radial Velocities: A Case Study of Kepler-21

open access: yesThe Astronomical Journal
We present a new analysis of Kepler-21, the brightest ( V = 8.5) Kepler system with a known transiting exoplanet, Kepler-21 b. Kepler-21 b is a radius valley planet ( R = 1.6 ± 0.2 R _⊕ ) with an Earth-like composition (8.38 ± 1.62 g cm ^–3 ), though its
Corey Beard   +28 more
doaj   +1 more source

The TESS–Keck Survey. XIX. A Warm Transiting Sub-Saturn-mass Planet and a Nontransiting Saturn-mass Planet Orbiting a Solar Analog

open access: yesThe Astronomical Journal
The Transiting Exoplanet Survey Satellite (TESS) continues to increase dramatically the number of known transiting exoplanets, and is optimal for monitoring bright stars amenable to radial velocity (RV) and atmospheric follow-up observations. TOI-1386 is
Michelle L. Hill   +47 more
doaj   +1 more source

Seeking Spectroscopic Binaries with Data-driven Models

open access: yesThe Astrophysical Journal
Data-driven stellar classification has a long and important history in astronomy, dating as far back as Annie Jump Cannon’s “by-eye” classifications of stars into spectral types, still used today.
Isabel Angelo   +2 more
doaj   +1 more source

A Homogeneous Catalog of Oscillating Solar-type Stars Observed by the Kepler Mission and a New Amplitude Scaling Relation Including Chromospheric Activity

open access: yesThe Astronomical Journal
We present a homogeneous catalog of global asteroseismic parameters and derived stellar parameters for 765 Kepler main-sequence and subgiant stars. The catalog was produced by reanalyzing all available Kepler DR25 short-cadence data using pySYD , an ...
Maryum Sayeed   +3 more
doaj   +1 more source

Revealing the Morpho-Kinematics of NGC 2371—A Planetary Nebula with a [WR] Central Star

open access: yesGalaxies
We present new high-dispersion optical spectra of the planetary nebula NGC 2371 obtained with the Manchester Echelle Spectrometer at the OAN-SPM 2.1 m telescope, complemented with 3D morpho-kinematic modelling using ShapeX.
Roberto Vázquez   +10 more
doaj   +1 more source

A Perfect Tidal Storm: HD 104067 Planetary Architecture Creating an Incandescent World

open access: yesThe Astronomical Journal
The discovery of planetary systems beyond the solar system has revealed a diversity of architectures, most of which differ significantly from our system.
Stephen R. Kane   +7 more
doaj   +1 more source

Preparing LIBS for in-situ measurements in JET tokamak: system overview and co-deposited layer thicknesses

open access: yesNuclear Materials and Energy
Laser-induced breakdown spectroscopy (LIBS) is a method for elemental composition analysis that has been proposed for fusion reactor safety diagnostics.
Jasper Ristkok   +16 more
doaj   +1 more source

The California Legacy Survey. V. Chromospheric Activity Cycles in Main-sequence Stars

open access: yesThe Astrophysical Journal Supplement Series
We present optical spectroscopy of 710 solar neighborhood stars collected over 20 years to catalog chromospheric activity and search for stellar activity cycles.
Howard Isaacson   +33 more
doaj   +1 more source

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