All posts by Nicholas Law

Physics and Astronomy

Evryscope @ AAS Winter 2019

The Evryscope team and collaborators are presenting talks and posters about Evryscope science results and papers at the AAS winter meeting:

Overview project-status and science-result iPoster, viewable every day in the poster sessions (official session is Wednesday evening), and online.

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
(Amy Glazier)

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)

Evryscope detects a superflare from Proxima Centauri

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.

Evryscope @ 2018 Winter AAS conference

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


Evryscope-North construction begins


We have started ordering the components of the Evryscope-North! The telescope will be based at the Mount Laguna Observatory (MLO). The Evryscope-North is funded by a collaboration of San Diego State University (SDSU), UNC-Chapel Hill  and the Research Corporation Scialog program.

Together with Evryscope-South, Evryscope-North will provide all-sky monitoring of essentially every object brighter than 16th magnitude . The two Evryscopes overlap in field of view, allowing truly-simultaneous multi-site multi-color observations over thousands of square degrees.

We expect to deploy the Evryscope-North at MLO in the summer of this year.

Presentations at SPIE Astronomy & Telescopes @ Edinburgh

We are presenting new Evryscope results in two presentations at the SPIE conference in Edinburgh:

Jeffrey Ratzloff, Nicholas M. Law, Octavi Fors, Philip Wulfken
Nicholas M. Law, Octavi Fors, Daniel del Ser, Hank Corbett, Jeffrey Ratzloff, Philip Wulfken

Project update

The Evryscope has been operational and fully robotic for one year, and has recorded over 60TB of data. All hardware is operational, and the system has survived lightning strikes, snowstorms and an 8th-magnitude earthquake without any damage!

Our team is currently finishing-off our data analysis pipeline, which performs image calibration, astrometry, source extraction,  light curve building and trend filtering. All results are inserted into our databases within the two minute time before the next exposure is taken, a data rate of 100Mb/sec.

We expect to offer the first high-quality light curves to the general community by the end of 2016.

Funding for the system is provided by the NSF/ATI and NSF/CAREER programs.

Below is a full Evryscope image, stitched together from all cameras.



A zoom into the white box in the image above.