We are happy to announce the NSF/MSIP development funding of the Argus Array prototype, the prototype for the next-generation Evryscope. Like the Evryscopes, Argus will cover the entire sky in each exposure, but with hundreds of quarter-meter telescopes tiled across a large dome, Argus will go far deeper.
Our NSF-funded Evryscope and exoplanets exhibit has opened at Morehead Planetarium. The exhibit includes a half-dome planetarium displaying real full-sky Evryscope images with gesture interactivity, an interactive activity where students learn to classify light curves and look for exoplanets, and interpretive material. See the WRAL (local news station) writeup here.
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 systematically studied. In a new ApJ Letter, we report event rates for these orbital flashes using the Evryscope Fast Transient Engine, a low-latency transient detection pipeline for the Evryscopes.
Ultraviolet light from giant stellar flares can destroy a planet’s habitability. New research from the Evryscope will help astrobiologists understand how much radiation planets experience during superflares and whether life could exist on worlds beyond our solar system.
Super flares are bursts of energy that are 10 to 1,000 times larger than the biggest flares from the Earth’s sun. These flares can bathe a planet in an amount of ultraviolet light huge enough to doom the chances of life surviving there.
We have for the first time measured the temperature of a large sample of super flares from stars, and the flares’ likely ultraviolet emissions. Our findings, published on arxiv Oct. 5 ahead of print in Astrophysical Journal, will allow researchers to put limits on the habitability of planets that are targets of upcoming planet-finding missions.
The Evryscope Team and collaborators have published new papers based on Evryscope data:
AAS-Nova has a great article on Ward Howard’s EvryFlare survey. His survey combines long-term high-cadence Evryscope observations with short-term, high-precision TESS data to measure extreme flare rates and rotation rates for cool stars, including some of the highest-priority TESS planet-search targets.
We are excited to announce that Jeff Ratzloff, the Evryscope mechanical designer and leader of our compact-objects and fast-transiting-exoplanets programs, has been selected to receive the 2020 Dean’s Distinguished Dissertation Award in the area of Mathematics, Physical Sciences & Engineering. The Dean’s Distinguished Dissertation Award recognizes the highest level of graduate student scholarship at UNC Chapel Hill; there is one award in physical sciences and mathematics each year.
The Evryscope team are presenting new surveys and results @ AAS 2020:
Two new papers from the Evryscope team detail the results of the Evryscope hot subdwarf binary and planet transit surveys:
Hot Subdwarf All Southern Sky Fast Transit Survey with the Evryscope (AJ 2020, in press)
Ratzloff, Jeffrey K.; Barlow, Brad N.; Nemeth, Peter; Corbett, Henry T.; Walser, Stephen; Galliher, Nathan W.; Glazier, Amy; Howard, Ward S.; Law, Nicholas M.
EVR-CB-001: An Evolving, Progenitor, White Dwarf Compact Binary Discovered with the Evryscope (ApJ 2019, 883 51R)
Ratzloff, Jeffrey K.; Barlow, Brad N.; Kupfer, Thomas; Corcoran, Kyle A.; Geier, Stephan; Bauer, Evan; Corbett, Henry T.; Howard, Ward S.; Glazier, Amy; Law, Nicholas M.
Several more results from this survey, which has found dozens of multiple-star systems in this mysterious phase of stellar evolution, are under review.
Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff, Amy Glazier, Octavi Fors, Daniel del Ser, Joshua Haislip
EvryFlare I: Long-term Evryscope Monitoring of Flares from the Cool Stars Across Half the Southern Sky (submitted to AJ)
Howard, Ward S.; Corbett, Hank; Law, Nicholas M.; Ratzloff, Jeffrey K.; Glazier, Amy L.; Fors, Octavi; del Ser, Daniel; Haislip, Joshua
Variables in the Southern Polar Region Evryscope 2016 Dataset (accepted to PASP)
Ratzloff, Jeffrey K.; Corbett, Henry T.; Law, Nicholas M.; Barlow, Brad N.; Glazier, Amy; Howard, Ward S.; Fors, Octavi; del Ser, Daniel; Trifonov, Trifon
Building the Evryscope: Hardware Design and Performance (accepted to PASP)
Jeffrey K. Ratzloff, Nicholas M. Law, Octavi Fors, Henry T. Corbett, Ward S. Howard, Daniel del Ser, Joshua Haislip
The Evryscope team and collaborators are presenting talks and posters about Evryscope science results and papers at the AAS winter meeting:
10am Tuesday (Terrestrial Planets and Habitability; 203.01):
Evryscope flares as probes of the space weather environments of Proxima b and the nearest rocky exoplanets (Ward Howard)
Tuesday posters (Extrasolar Planets: Characterization & Theory; 247.05):
Evryscope and K2 Constraints on TRAPPIST-1 Superflare Occurrence and Planetary Habitability
Wednesday posters (Surveys and Large Programs; 363.11):
All-sky rapid transient searches with the Evryscope network (Hank Corbett)
Wednesday posters (Variable Stars; 360.16):
Evryscope Observations of Post-Common-Envelope Hot Subdwarf Systems (Kyle Corcoran)
2pm Thursday (Extrasolar Planets: Detection – Transit and Microlensing Searches):
Fast Cadence Planet-searches with the All-sky, Gigapixel-scale Evryscope (Jeffrey Ratzloff)
Thursday posters (Stars In All Their Glory; 464.03):
Evryscope Photometry of the New Hot Subdwarf Reflection Effect Binary EC 01578-1743 (Stephen Walser)
We’ve completed a successful deployment of the Northern Evryscope. The system is currently undergoing commissioning.
Evryscope measured the rotation period of K2-3, a planet-host with too long a rotation period to be measured directly in K2 (or eventually TESS) data. We’re happy to provide data for astronomers interested in similar measurements of other targets.
Evryscope helped characterize a young, eccentric and quadruple stellar system, detecting starspot rotational modulation (a clear detection at the 4mmag level!)
The Evryscope has detected a superflare that briefly made the tiny star Proxima Centauri, the nearest star to our Sun, 70x brighter. Proxima b is a terrestrial-mass planet in the habitable-zone of Proxima Centauri. Proxima Centauri’s high stellar activity however casts doubt on the habitability of Proxima b: sufficiently bright and frequent flares may destroy the planet’s ozone layer, allowing lethal levels of UV flux to reach its surface. In March 2016, the Evryscope observed the first naked-eye-visible superflare detected from Proxima Centauri.
Proxima increased in brightness by a factor of ~68 during the superflare, reaching a brightness just visible to the naked eye at dark sites (and easily seen with binoculars, if someone was looking in the right direction). It’s probably worth mentioning that some people on Twitter have misinterpreted our paper to suggest that we’re claiming this event would have been easily visible to most people at most sites — which it would not have been, and which don’t claim in the paper. We just use “naked-eye” as a compact way to say the event reached a brightness in visible-light that can be detected by the human eye without optical aids under ideal conditions, to give an idea of how bright it was compared to most astronomical events.
Our statistics suggest that Proxima produces a superflare around five times a year — and some of those flares would be even brighter than the one we saw, perhaps even to the level that they could be easily visible to many people around the world. So there’s a (very) small chance that if you’re in the Southern Hemisphere and look up at Proxima Centauri, you could see a superflare going off!
In our paper, we show that the repeated flaring is sufficient to reduce the ozone of an Earth-like atmosphere by 90% within five years. We estimate complete depletion occurs within several hundred kyr. The UV light produced by the Evryscope superflare reached the surface with ~100x the intensity required to kill simple UV-hardy microorganisms, suggesting that life would struggle to survive in the areas of Proxima b exposed to these flares.
Above: the Evryscope discovery of the first naked-eye superflare from Proxima Centauri. Proxima got 35x brighter in a single Evryscope two-minute exposure; over the shorter timescale of the human eye Proxima increased in brightness by a factor of ~70x.
The Evryscope team is presenting a variety of results at the Winter AAS conference in Washington DC:
|Evryscope project overview||Nicholas Law||NSF Fellows Workshop, Monday|
|Fast cadence planet-searches with the all-sky, gigapixel-scale Evryscope||Jeff Ratzloff||204.05, Detection of Extrasolar Planets II, Wednesday|
|Rapid All-Sky Transient Discovery and Analysis with Evryscope||Hank Corbett||Surveys and Large Programs I, 231.06, Wednesday|
|Stellar activity for every TESS star in the Southern sky||Ward Howard||Extrasolar Planets V, 310.03, Thursday|
|Updated O-C Diagrams for Several Bright HW Vir Binaries Observed with the Evryscope||Kyle Corcoran & Brad Barlow||Tuesday, 150.23|
|The Evryscopes: monitoring the entire sky for exciting events||Nicholas Law||Thursday, 354.12|