Archive for June 8th, 2022

U Sco update

June 8, 2022

Within a day, the nova reached a peak magnitude of 7.8, then dropped two magnitudes, becoming around 5 times dimmer in actual brightness (magnitude is logarithmic).

The AAVSO Alert Notice details the decline of the last outburst over a few months and flares with an amplitude of around half a magnitude that began several days after the peak, for which the mechanism is unknown.

Outburst of the Recurrent Nova U Sco

June 8, 2022

In late September 2021, I wrote about the recurrent nova U Scorpii: Waiting for U Sco and Waiting for U Sco: nearby gamma ray transient detected.

The last image I took of the region around U Sco in September showed no sign of it, but within the last day it has undergone an outburst, and appears to have quickly peaked, as per previous events (the last being in January 2010) before declining again. The nova reached a visual magnitude of 7.8 on June 7 2022 up from its usual magnitude 18 or thereabouts, a difference in brightness of around 25 times (each magnitude being a factor of 2.512 brighter than the whole number magnitude on either side of it). As I write, U Sco has declined to around magnitude 8.4.

The light curves show the current and 2010 outburst, and a close up of the current outburst. It’s interesting note that there appears to have been some evidence of an increase in magnitude in the few months leading up to the outburst.

I took a DSLR image of the region around the nova tonight. U Sco is marked with a red arrow.

While I don’t have images that are suitable for DSLR photometry from tonight (the sky was less than ideal), nor did I have the chance to make a visual (binocular or telescope) observation, from the image I estimate the nova’s magnitude to be around 8.4 (magnitude 8.3 and 8.6 comparison stars are marked with green arrows), which is consistent with the current photometry in the AAVSO International Database.

The following images show the U Sco region tonight (June 2022) and late last September for comparison, in different sky conditions and positions on the sky. The second image has been rotated to match the current event’s sky rotation. Flicking up and down between the images will help reveal the nova, aided by the arrowed image above if necessary.

June 2022 outburst (5 seconds, ISO 800, f2.0, Canon 1100D)
U Sco region in late September 2021 (3 seconds, ISO 800, f2.0, Canon 1100D)

For more information about recurrent novae, I gave a talk in early September 2021 to ASSA about another recurrent nova RS Oph. See also this AAVSO forum page regarding the current outburst.

EDIT: Here is the AAVSO alert notice: https://www.aavso.org/aavso-alert-notice-779