A5004209010- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Space Exploration and Technology
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Inertial Sensor and Navigation
- High-pressure geophysics and materials
- Advanced Statistical Methods and Models
- Crystal Structures and Properties
- Planetary Science and Exploration
The Ohio State University
2018-2025
Center for Astrophysics Harvard & Smithsonian
2024-2025
Harvard University
2024
Instituto de Astrofísica de Canarias
2012
ABSTRACT A gold standard for the study of M dwarfs is eclipsing binary CM Draconis. It rare because it bright (Jmag = 8.5) and contains twin fully convective stars on an almost perfectly edge-on orbit. Both masses radii were previously measured to better than 1 per cent precision, amongst best known. We use 15 sectors data from Transiting Exoplanet Survey Satellite (TESS) show that Draconis gift keeps giving. Our paper has three main components. First, we present updated parameters, with...
Abstract We analyzed the light curves of 1376 early-to-late, nearby M dwarfs to search for white-light flares using photometry from All-Sky Automated Survey Supernovae. identified 480 with at least one potential flare employing a simple statistical algorithm that searches sudden increases in V -band flux. After more detailed evaluation, we 62 individual on stars. The event amplitudes range <?CDATA $0.12\lt {\rm{\Delta }}V\lt 2.04$?> mag. Using classical models, place lower limits energies...
M dwarfs are the most common stars in galaxy, with long lifespans, a high occurrence rate of rocky planets, and close-in habitable zones. However, stellar activity form frequent flaring any associated coronal mass ejections may drive atmospheric escape bombardment radiation high-energy particles, drastically impacting habitability these systems. The latitude where flares occur determines space weather that exoplanets subject to, particle events equatorial producing significant erosion....
Abstract We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by NASA Transiting Exoplanet Survey Satellite. transits G-type star ( V = 12.6 mag) with mass, radius, effective temperature <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mo>⋆</mml:mo> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.00</mml:mn> <mml:msubsup> <mml:mn>5</mml:mn>...
Abstract M dwarfs are the most common stars in galaxy, with long lifespans, a high occurrence rate of rocky planets, and close-in habitable zones. However, stellar activity form frequent flaring any associated coronal mass ejections may drive atmospheric escape bombardment radiation energy particles, drastically impacting habitability these systems. The latitude where flares occur determines space weather that exoplanets subject to, particle events equatorial producing significant erosion....
Abstract We present the discoveries of KELT-25 b (TIC 65412605, TOI-626.01) and KELT-26 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A stars. The transit signals were initially detected by KELT survey subsequently confirmed Transiting Exoplanet Survey Satellite (TESS) photometry. is on a 4.40 day orbit around V = 9.66 star CD-24 5016 ( <?CDATA ${T}_{\mathrm{eff}}={8280}_{-180}^{+440}$?> K, M ⋆ ${2.18}_{-0.11}^{+0.12}$?> ⊙ ), while 3.34 9.95 HD 134004...
Abstract We investigate and compare the composition of M-dwarf planets in systems with only one known planet (“singles”) to those residing multiplanet (“multis”) fundamental properties their host stars. restrict our analysis directly measured masses radii, which comprise a total 70 planets: 30 singles 40 multis 19 systems. bulk densities for full sample, includes ranging size from 0.52 R ⊕ 12.8 , find that single have significantly lower on average than multis, we cannot attribute selection...
We present a reanalysis of the K2-106 transiting planetary system, with focus on composition K2-106b, an ultra-short period, super-Mercury candidate. globally model existing photometric and radial velocity data derive mass radius for K2-106b $M_{p} = 8.53\pm1.02~M_{\oplus}$ $R_{p} 1.71^{+0.069}_{-0.057}~R_{\oplus}$, which leads to density $\rho_{p} 9.4^{+1.6}_{-1.5}$ $\rm g~cm^{-3}$, significantly lower value than previously reported in literature. use planet interior models that assume...
Abstract We measure abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample 86 metal-poor (−2 ≲ [Fe/H] −1) subgiant stars the solar neighborhood. Abundances are derived from high-resolution spectra taken with Potsdam Echelle Polarimetric and Spectroscopic Instrument on Large Binocular Telescope, modeled using iSpec MOOG. By carefully quantifying impact photon-noise (<0.05 dex for all elements), we robustly intrinsic scatter abundance ratios. At fixed [Fe/H],...
ABSTRACT M-dwarfs are the most abundant stars in galaxy and popular targets for exoplanet searches. However, their intrinsic faintness complex spectra inhibit precise characterization. We only know of dozens with fundamental parameters mass, radius, effective temperature characterized to better than a few per cent. Eclipsing binaries remain robust means stellar Here we present two from Binary Low Mass (EBLM) survey that were observed K2: EBLM J0055-00 J2217-04. Combined HARPS CORALIE...
Abstract We present the discovery of KELT-24 b, a massive hot Jupiter orbiting bright ( V = 8.3 mag, K 7.2 mag) young F-star with period 5.6 days. The host star, (HD 93148), has T eff <?CDATA ${6509}_{-49}^{+50}$?> K, mass M * ${1.460}_{-0.059}^{+0.055}$?> ⊙ , radius R 1.506 ± 0.022 and an age ${0.78}_{-0.42}^{+0.61}$?> Gyr. Its planetary companion (KELT-24 b) P 1.272 0.021 J ${5.18}_{-0.22}^{+0.21}$?> from Doppler tomographic observations, we find that planet’s orbit is well-aligned to its...
Abstract Lava worlds are a potential emerging population of Super-Earths that on close-in orbits around their host stars, with likely partially molten mantles. To date, few studies have addressed the impact magma observed properties planet. At ambient conditions, is less dense than solid rock; however, it also more compressible increasing pressure. Therefore, unclear how large-scale oceans affect planet observables, such as bulk density. We update ExoPlex , thermodynamically self-consistent...
Abstract Using mass–radius composition models, small planets ( R ≲ 2 ⊕ ) are typically classified into three types: iron-rich, nominally Earth-like, and those with solid/liquid water and/or atmosphere. These classes generally expected to be variations within a compositional continuum. Recently, however, Luque & Pallé observed that potentially Earth-like around M dwarfs separated from lower-density population by density gap. Meanwhile, the results of Adibekyan et al. hint iron-rich FGK...
A gold standard for the study of M dwarfs is eclipsing binary CM Draconis. It rare because it bright ($J_{\rm mag}=8.5$) and contains twin fully convective stars on an almost perfectly edge-on orbit. Both masses radii were previously measured to better than $1\%$ precision, amongst best known. We use 15 sectors data from Transiting Exoplanet Survey Satellite (TESS) show that Draconis gift keeps giving. Our paper has three main components. First, we present updated parameters, with...
ABSTRACT We explore the prospects for Twinkle to determine atmospheric composition of nearby terrestrial-like planet LTT 1445 Ab, including possibility detecting potential biosignature ammonia (NH3). At a distance 6.9 pc, this system is second closest known transiting and will be observed through transmission spectroscopy with upcoming mission. Although Ab has been suggested candidate Hycean world, constraints on interior based its mass radius suggests that lacks substantial water layer,...
We report and characterize a white-light superflare on previously undiscovered M dwarf detected by the ASAS-SN survey. Employing various color-magnitude color-spectral type relationships, we estimate several stellar parameters, including quiescent V-band magnitude, from which derive flare amplitude of $\Delta V \sim 10$. determine an r-band absolute magnitude $M_{r} = 11.4$, consistent with mid-M dwarf, approximate distance to source $2.2$ kpc. Using classical-flare models, infer energy...
Abstract Well-characterised M-dwarfs are rare, particularly with respect to effective temperature. In this letter we re-analyse two benchmark in eclipsing binaries from Kepler/K2: KIC 1571511AB and HD 24465AB. Both have temperatures reported be hotter or colder by ≈1000 K comparison both models the majority of other literature. By modelling secondary eclipses original data new TESS derive significantly different temperatures: 2865 ± 27 for 1571511B 3081 32 24465B 3114 K2. These not outliers....
We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by NASA Transiting Exoplanet Survey Satellite (TESS). transits G-type star (V = 12.6 mag) with mass, radius, effective temperature $M_{\star} =1.005^{+0.064}_{-0.061} M_{\odot}$, $R_{\star} 1.055^{+0.040}_{-0.037} R_{\odot}$, $T_{\rm eff} 5640 \pm 110$ K. obtained follow-up ground-based photometry from Las Cumbres Observatory (LCO) Antarctic Search for ExoPlanets (ASTEP)...
Abstract Given their location on the Hertzsprung-Russell (H-R) diagram, thoroughly characterized subgiant stars can place stringent constraints a wide range of astrophysical problems. Accordingly, they are prime asteroseismic targets for Transiting Exoplanet Survey Satellite (TESS) mission. In this work, we infer stellar properties sample 347 subgiants located in TESS Continuous Viewing Zones, which select based likelihood showing oscillations. We investigate how well be using classical...
Abstract We present analytic estimates of the fractional uncertainties on mass, radius, surface gravity, and density a transiting planet, using only empirical or semi-empirical measurements. first express these parameters in terms transit photometry radial velocity (RV) observables, as well stellar radius R ⋆ , if required. In agreement with previous results, we find that, assuming circular orbit, gravity planet ( g p ) depends RV parameters, namely period P depth δ semi-amplitude K duration...
TOI-1259 consists of a transiting exoplanet orbiting main sequence star, with bound outer white dwarf companion. Less than dozen systems this architecture are known. We conduct follow-up spectroscopy on the TOI-1259B using Large Binocular Telescope (LBT) to better characterise it. observe only strong hydrogen lines, making DA dwarf. see no evidence heavy element pollution, which would have been planetary material around Such pollution is seen in ~ 25 - 50% dwarfs, but it unknown if rate...
Abstract We present moderate resolution near-infrared spectra in the H , J and K band of M-dwarf hosts to candidate transiting exoplanets discovered by NASA’s K2 mission. employ known empirical relationships between spectral features physical stellar properties measure effective temperature, radius, metallicity, luminosity our sample. Out an initial sample 56 late-type stars we identify 35 objects as M dwarfs. For that subsample, derive temperatures ranging from 2870 4187 K, radii 0.09–0.83...
We explore the prospects for Twinkle to determine atmospheric composition of nearby terrestrial-like planet LTT 1445 Ab, including possibility detecting potential biosignature ammonia (NH$_{3}$). At a distance 6.9 pc, this system is second closest known transiting and will be observed through transmission spectroscopy with upcoming mission. equipped 0.45 m telescope, covers spectral wavelength range 0.5 - 4.5 $\mu$m simultaneously resolving power between 50 70, designed study exoplanets,...
We investigate and compare the composition of M-dwarf planets in systems with only one known planet (``singles") to those residing multi-planet (``multis") fundamental properties their host stars. restrict our analysis directly measured masses radii, which comprise a total 70 planets: 30 singles 40 multis 19 systems. bulk densities for full sample, includes ranging size from $0.52 R_{\oplus}$ $12.8R_\oplus$, find that single have significantly lower on average than multis, we cannot...
Lava worlds are a potential emerging population of Super-Earths that on close-in orbits around their host stars with likely partially molten mantles. To date, few studies address the impact magma observed properties planet. At ambient conditions is less dense than solid rock; however, it also more compressible increasing pressure. Therefore, unclear how large-scale oceans affect planet observables, such as bulk density. We update ExoPlex, thermodynamically self-consistent interior software,...