FT Schools Combine to do Research

FT researchers have combined with regular and new FT users in a series of themed observing days this week.

Last Friday’s observing run was thwarted by bad weather in Hawaii, so it was re-arranged for Monday.

The target we were after was known as IGR J00291+5934, an accreting
Millisecond X-ray Pulsar (MSXP). It’s made up of two components, one
being a neutron star, the other a 'normal' star, with a mass about 5-8%
that of our Sun.

Material is gravitationally drawn from the 'normal' low-mass star onto
the pulsar via a disc of material that surrounds the pulsar. From
time-to-time, the disc becomes unstable and the system becomes
brighter. 00291 (to its friends) is currently undergoing one of these
outbursts

This system has recently risen in brightness from a magnitude of R ~
23, where it was not visible to the FT, to a magnitude of ~ 18. This
rise has been accompanied by a rise in the amount of X-rays detected by
X-ray satellites such as Swift and RXTE.

Whilst it's not uncommon for some of these systems to brighten
dramatically like this, 00291 is extremely rare in that it has repeated
this behaviour twice in the last month.

We can see the ‘before’ and ‘after’ images below.

On Tuesday and Wednesday, we shifted our attention to a similar source, known as SAX J1808.8-3658.

 The top left image is from 6 days ago and the top right from Tuesday
(Glenlola). For comparison, the lower one is from about a month ago. We
can see straight away that there’s something there that wasn’t apparent
on earlier observations.

The left-hand image is from today (Oundle). For comparison, the
right-hand one is from about a month ago. Again, we can see that
something has appeared.

This confirms the fact that this object is in outburst – it’s much,
much brighter at the moment than previously. We suspect that this
relates to material being drawn off the 'normal' star and dragged onto
the neutron star.

The two hours worth of data that we got today can be added to
yesterday's observations to help us understand the system better.
Today's data by itself gives us a full orbital period for this system,
from which we'll be producing a lightcurve.

We thank the following the staff and students of the following schools and groups ….

Paulet High School

The Kingsley School

Czacki High School

St. Brigid’s School

St. David’s Catholic College

University College Cork

Glenlola Collegiate

South Downs Planetarium

Oundle School

Dartford Grammar School

Portsmouth Grammar School