Observation by Stewart Bean: Superhumps from IX Dra

Uploaded by

Stewart John Bean

Observer

Stewart Bean

Observed

2019 Sep 13 - 12:05

Uploaded

2020 Oct 06 - 12:20

Objects

Lightcurve
Variable star

Equipment

TESS satellite, JD2458740
Lightkurve
in a Python environment

Exposure

2 min cadence, 100 mm obj, 600-1000nm filter.

Location

Somewhere between Earth and Moon

Target name

IX Dra

Title

Superhumps from IX Dra

About this image

I have downloaded TESS data from the MAST site ( where most variable stars will have some TESS light curves) and plotted the superoutburst from Sept 2019. TESS stares continuously at a fixed point for about 27 days recording red light from about 20,000 targets. Stars round the ecliptic poles receive almost continuous coverage for a whole 12 months campaign so those in Draconis are well favoured.

The plot shows the first part of a superoutburst with well defined superhumps. The Y axis is in raw flux and not in magnitude.

Files associated with this observation

IX Dra superhumps at 1740.png (46.1 kB)

Like this image

David Basey, Mike Harlow, Dr Andrew Smith, Peter Mulligan, Graham Winstanley, Stewart John Bean, Dr Paul Leyland, Jeremy Shears

Comments

Dr Paul Leyland, 2020 Oct 19 - 19:03 UTC

Have you analyzed the period of the superhumps?

A light curve folded on that period should be well worth posting.

Stewart John Bean, 2020 Oct 20 - 15:11 UTC

"Lightkurve" and its periodogram give the following results for the superhump period.

Each TESS Sector is ~27 days of data at 2 min cadence with a gap of one day in the middle to download the results.

0.06705 TESS sector 16

0.06702 TESS Sector 18

0.06703 TESS Sector 25

With no superhumps in the data set:

0.06474 TESS Sector 15

0.06747 TESS Sector 24 . This data set does not sure a strong peak in the periodogram.

0.06479 TESS Sector 26

VSX gives the orbital period as 0.0648 day. So we have a superhump period that is 3.4% longer than P(orb).

Stewart

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