Explanipedia

EFTE-SOAR: Two Giant M Dwarf Flares with Rapid Spectroscopic Follow-up Open

Hank Corbett, Nathan Galliher, Amy Glazier, Ramses Gonzalez Chavez, Nicholas M. Law , et al. · 2025

We present time-series optical spectroscopy of two stellar flares with complex multi-peaked light curves: a erg flare from an M8 ultra-cool dwarf, and a erg superflare from an M4 field star. Both f…

The Evryscope Fast Transient Engine: Real-time Detection for Rapidly Evolving Transients Open

Hank Corbett, Jonathan Carney, Ramses Gonzalez, O. Fors, Nathan Galliher , et al. · 2023

Astrophysical transients with rapid developments on subhour timescales are intrinsically rare. Due to their short durations, events like stellar superflares, optical flashes from gamma-ray bursts, and shock breakouts from young supernovae …

The Evryscope Fast Transient Engine: Real-Time Detection for Rapidly Evolving Transients Open

Hank Corbett, Jonathan Carney, Ramses Gonzalez, O. Fors, Nathan Galliher , et al. · 2023

Astrophysical transients with rapid development on sub-hour timescales are intrinsically rare. Due to their short durations, events like stellar superflares, optical flashes from gamma-ray bursts, and shock breakouts from young supernovae …

Multiwavelength Photometry and Progenitor Analysis of the Nova V906 Car Open

J. Wee, N. Blagorodnova, B.E. Penprase, J.P. Facey, T. Morioka , et al. · 2022

We present optical and infrared photometry of the classical nova V906 Car, also known as Nova Car 2018 and ASASSN-18fv, which was discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) on 2018 March 16.32 UT (MJD 58193.0). The…

Robotilter: An automated lens/CCD alignment system for the Evryscope Open

Jeffrey K. Ratzloff, Nicholas M. Law, H.T. Corbett, O. Fors, Daniel del Ser · 2022

Camera lenses are increasingly used in wide-field astronomical surveys due to their high performance, wide field-of-view (FOV) unreachable from traditional telescope optics, and modest cost. The machining and assembly tolerances for commer…

Orbital foregrounds for ultra-short duration transients Open

Hank Corbett, Nicholas M. Law, Alan Vasquez Soto, William A. Howard, Amy Glazier , et al. · 2022

Reflections from objects in Earth orbit can produce subsecond, star-like optical flashes similar to astrophysical transients. Reflections have historically caused false alarms for transient surveys, but the population has not been systemat…

Investigating exoplanet habitability and the stellar magnetism of cool stars across half the southern sky via superflares, starspots, and stellar rotation Open

Ward S. Howard, N. Law, Hank Corbett, Jeffrey K. Ratzloff, Amy Glazier , et al. · 2021

Stellar flares are stochastic events that occur when a star's magnetic field re-connects, releasing intense radiation across the electromagnetic spectrum. Rocky planets in the habitable zones of M-dwarfs are often subjected to superflares,…

Constraints on Post-Superflare Exo-Auroral Emission with SOAR and the Evryscope Fast Transient Engine Open

Amy Glazier, Nicholas M. Law, Hank Corbett, Ward S. Howard, Alan Vasquez Soto , et al. · 2021

High-energy particles from M-dwarf superflares--flares with energy $\geq 10^{33}$ erg--can dramatically impact habitable-zone planets around these cool stars, with possible effects including the excitation of intense aurorae as particles…

A missing piece of the habitability puzzle: the first statistical sample of M-dwarf superflare temperatures observed with multi-facility, multi-wavelength monitoring Open

Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff, Nathan Galliher , et al. · 2021

Superflares (flares with energy 10^33 erg or greater) provide the dominant source of biologically-relevant UV radiation to rocky planets in M-dwarf habitable zones, altering planetary atmospheres and conditions for prebiotic chemistry and …

Revisiting the HD 21749 planetary system with stellar activity modelling Open

Tianjun Gan, Sharon X. Wang, Johanna Teske, Shude Mao, Ward S. Howard , et al. · 2020

HD 21749 is a bright (V = 8.1 mag) K dwarf at 16 pc known to host an inner terrestrial planet HD 21749c as well as an outer sub-Neptune HD 21749b, both delivered by Transiting Exoplanet Survey Satellite (TESS). Follow-up spectroscopic obse…

Orbital Foregrounds for Ultra-short Duration Transients Open

Hank Corbett, Nicholas M. Law, Alan Vasquez Soto, Ward S. Howard, Amy Glazier , et al. · 2020

Reflections from objects in Earth orbit can produce subsecond, star-like optical flashes similar to astrophysical transients. Reflections have historically caused false alarms for transient surveys, but the population has not been systemat…

Evryscope-South Survey of Upper- and Pre-main Sequence Solar Neighborhood Stars Open

Nathan Galliher, Jeffrey K. Ratzloff, Hank Corbett, Nicholas M. Law, Ward S. Howard , et al. · 2020

Using photometric data collected by Evryscope-South, we search for nearby young variable systems on the upper-main sequence (UMS) and pre-main sequence (PMS). The Evryscopes are all-sky high-cadence telescope arrays operating in the Northe…

EVR-CB-004: An Inflated Hot Subdwarf O Star + Unseen WD Companion in a Compact Binary Discovered with the Evryscope Open

Jeffrey K. Ratzloff, Thomas Kupfer, B. N. Barlow, D. P. Schneider, T. R. Marsh , et al. · 2020

We present the discovery of EVR-CB-004, a close binary with a remnant stellar core and an unseen white dwarf (WD) companion. The analysis in this work reveals that the primary is potentially an inflated hot subdwarf (sdO) and more likely i…

EvryFlare. II. Rotation Periods of the Cool Flare Stars in TESS across Half the Southern Sky Open

Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff, Nathan Galliher , et al. · 2020

We measure rotation periods and sinusoidal amplitudes in Evryscope light curves for 122 two-minute K5–M4 TESS targets selected for strong flaring. The Evryscope array of telescopes has observed all bright nearby stars in the south, produci…

Robotilter: an automated lens/CCD alignment system for the Evryscope Open

Jeffrey K. Ratzloff, Nicholas M. Law, Hank Corbett, O. Fors, Daniel del Ser · 2020

Camera lenses are increasingly used in wide-field astronomical surveys due to their high performance, wide field-of-view (FOV) unreachable from traditional telescope optics, and modest cost. The machining and assembly tolerances for commer…

The Robotilter: An Automated Lens / CCD Alignment System for the\n Evryscope Open

Jeffrey K. Ratzloff, Nicholas M. Law, Hank Corbett, O. Fors, Daniel del Ser · 2020

Camera lenses are increasingly used in wide-field astronomical surveys due to\ntheir high performance, wide field-of-view (FOV) unreachable from traditional\ntelescope optics, and modest cost. The machining and assembly tolerances for\ncom…

EVR-CB-001: An Evolving, Progenitor, White Dwarf Compact Binary Discovered with the Evryscope Open

Jeffrey K. Ratzloff, B. N. Barlow, Thomas Kupfer, Kyle A. Corcoran, S. Geier , et al. · 2019

We present EVR-CB-001, the discovery of a compact binary with an extremely low-mass (0.21 ± 0.05 M ⊙ ) helium core white dwarf progenitor (pre-He WD) and an unseen low-mass (0.32 ± 0.06 M ⊙ ) helium white dwarf (He WD) companion. He WDs ar…

EVR-CB-001: An evolving, progenitor, white dwarf compact binary\n discovered with the Evryscope Open

Jeffrey K. Ratzloff, B. N. Barlow, Thomas Kupfer, Kyle A. Corcoran, S. Geier , et al. · 2019

We present EVR-CB-001, the discovery of a compact binary with an extremely\nlow mass ($.21 \\pm 0.05 M_{\\odot}$) helium core white dwarf progenitor (pre-He\nWD) and an unseen low mass ($.32 \\pm 0.06 M_{\\odot}$) helium white dwarf (He\nW…

EvryFlare II: Rotation Periods and Starspot Coverage of Cool Active Stars Throughout the Spin-down Process Open

Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff, Amy Glazier , et al. · 2019

We measure photometric rotation periods and starspot amplitudes in Evryscope light curves for 113 cool stars selected to have strong flaring. The Evryscope array of small telescopes has observed all bright nearby stars in the Southern sky,…

Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, and d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits Open

Molly Kosiarek, Ian J. M. Crossfield, Kevin K. Hardegree-Ullman, John H. Livingston, Björn Benneke , et al. · 2019

We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer…

Young and Eccentric: The Quadruple System HD 86588 Open

Andreï Tokovinin, Hank Corbett, O. Fors, Ward S. Howard, Nicholas M. Law , et al. · 2018

High-resolution spectroscopy and speckle interferometry reveal the young star HD 86588 as a quadruple system with a three-tier hierarchy. The 0.″3 resolved binary A,B with an estimated period around 300 years contains the 8-yr pair Aa,Abc …

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