Variable Stars

Introduction

The Society has a long history of variable star observing from its formation and members have contributed several thousand observations to the BAA Variable Star Section.
Both experienced observers and newcomers are encouraged to participate in variable star observing. Since the late 1980’s though, photoelectric photometry has been the prominent form of observing with the result that the number of visual observations has declined, this has since been superseded by CCD photometry in the mid 90’s and this is now the main tool for photometric studies.

Nomenclature

Variable stars are labelled after the constellation that they reside in, in order of discovery, the first variable in a constellation is given the designation ‘R’ and subsequent variables are labelled as follows…
R, S, T, U, V, W, X, Y, Z however this didn’t prove to be enough! So the labelling continues with…
RR, RS… RZ,
SR, SS, and on until you reach ZZ, this also was inadequate, so the labelling continues from
AA through to QZ giving a total of 334 variables in any constellation, after this variables are numbed and have a preceding ‘V’, starting with V335 in recognition of the 334 variables before it.

Types of Variable

There are two broad categories of variable star, intrinsic and extrinsic variables.

Intrinsic

Vary due to the internal nature of the star, for example a star that is pulsating.

Extrinsic

Vary due to external influences, for example binary stars eclipsing each other.

Further Reading

BAA Variable Star Section | AAVSO | Wikipedia

Exo-Planet HAT-P-30b

HAT-P-30b is a transiting hot Jupiter around a 1.25 solar mass star in the constellation of Hydra near the boarder of cancer. Martin Crow and Simon Dawes observed this exo-planet transiting its parent start part of the exoclock project, to refine transit predictions...

Observation od EXO-Planet XO-2Nb

XO-2Nb is an exo-planet in Lynx it has an orbital period of 2.6159 days. Observed by Martin Crow as part of the Exoclock project. More info: ExoClock project https://www.exoclock.space/project And the paper that it relates to:...

Observation of EXO-Planet HAT-P-1b

HAT-P-1b is an exo-planet in Lacerta it has an orbital period of 4.4652968 days Observation bt Martin Crow as part of Exoclock project. More info: ExoClock project https://www.exoclock.space/project And the paper that it relates to:...

Observation of EXO-Planet HAT – P – 16b

HAT-P-16b is an exo planet in Andromeda with a period of 2.77596 days. Observed by Martin Crow as part of the ExoClock project More info: ExoClock project https://www.exoclock.space/project And the paper that it relates to:...

Observation of Exo-Planet KELT 16b

KELT-16b is an exo-planet in Cygnus, member Martin Crow measured the brightness of the parent star (KELT48) in order to capture the small drop in brightness when the planet transits the face of the star, this is a very subtle observation that requires a lot of...

Observation of Exo-Planet WASP-48b

Exo-Planet WASP 48b is a planet discovered around star WASB 48 in the constellation of Cygnus. Member, Martin Crow measured the brightness of WASP 48, using the same techniques used for variable star observations – although the changed in brightness are very...

Observation of Exo-Planet HD 189733b

HD 189733 b is an extrasolar planet, in the constellation of Vulpecula. According to Wikipedia it is 64.5 light years away. Member, Martin Crow, used the same techniques used for observing variable stars to detect the drop in light from the parent star as the planet...

First Light with a new CCD on RS Boo

A phase curve from Martin Crow’s first four sets of  test observations using the pulsating star RS Boo as a target. Period 0.37733days. Acquired with 235mm SCT @ f6.3 and SX694 camera and sxcon software . Processed with AIJ and VSS...

2013 Nova in Delphinus

Nova in Delphinus Nova Delphinus 2013 discovered by Koichi Itagaki of Yamagata, Japan, in an image taken on Aug. 14. Before erupting, the nova was a magnitude +17 star reaching a peak magnitude of +4.5 on Aug. 16 2013. Member Honor Wheeler, taking images of the night...