{"id":2379,"date":"2017-06-11T14:00:04","date_gmt":"2017-06-11T13:00:04","guid":{"rendered":"http:\/\/www.popastro.com\/main_spa1\/variablestar\/?p=2379"},"modified":"2017-11-23T15:44:58","modified_gmt":"2017-11-23T15:44:58","slug":"miras-near-maximum","status":"publish","type":"post","link":"https:\/\/www.popastro.com\/variablestar\/2017\/06\/11\/miras-near-maximum\/","title":{"rendered":"Miras near maximum"},"content":{"rendered":"

Four of the Mira type variable stars on the section’s programme – T Cep, R Ser, R UMa and T UMa – are currently near maximum and readily visible in binoculars.<\/p>\n

A fifth – R Leonis – is also near maximum but is already disappearing into the evening twilight.<\/p>\n

\"T<\/p>\n

 <\/p>\n

T Cephei<\/strong>\u00a0is predicted to reach maximum around mid June.<\/p>\n

The peak brightness has, over the years, averaged around magnitude 6.0.<\/p>\n

In 2017, it had already reached around mag 6.8 by early May, but then seemed to “stall”.<\/p>\n

Observations in early June have hinted that it might have started brightening again.<\/p>\n

T Cephei is fairly easy to track down as it lies not far from the star Beta Cephei, as can be seen in this chart which covers approx 8 degrees by 6 degrees of sky and has north at the top. The chart also labels comparison stars with their magnitudes (decimal points omitted).<\/p>\n

 <\/p>\n

\"R<\/p>\n

 <\/p>\n

R Serpentis<\/strong>\u00a0isn’t actually due at maximum until around mid-July, but seems to be well “ahead of schedule” in its rise to maximum.<\/p>\n

It was already visible in larger binoculars by mid May and was at around magnitude 7.4 by early June.<\/p>\n

The long-term average peak brightness has been about mag 6.9, but maybe in 2017 it is either going to exceed this by some way, or is producing a peak well ahead of schedule.<\/p>\n

R Serpentis lies just\u00a0 below the “head” of the constellation of Serpens Caput, which in turn lies just below Corona Borealis.<\/p>\n

The accompanying finder chart, which is approx 7 degrees by 5 degrees and has north at the top, shows the location of R Serpentis and its comparison stars.<\/p>\n

 <\/p>\n

\"R<\/p>\n

 <\/p>\n

R Ursae Majoris<\/strong>\u00a0also seems to be ahead of schedule.<\/p>\n

Peak brightness is predicted for the beginning of July but it had reached mag 7.3 by early June – close to its long-term average peak of mag 7.2.<\/p>\n

R UMa lies to the “top right” of the main stars of the ‘Plough’. The ‘pointers’, (Alpha and Beta UMa) are a good starting point when locating R UMa.<\/p>\n

The accompanying chart, which is approx 7 degrees by 4 degrees and has north at the top, shows the location of R UMa in more detail and labels comparison stars with their magnitudes (decimal points omitted).<\/p>\n

 <\/p>\n

\"T<\/p>\n

 <\/p>\n

T Ursae Majoris<\/strong>\u00a0is another Mira variable that seems to be producing a brighter maximum than usual in 2017 and one that is also somewhat early.<\/p>\n

The 2017 maximum is predicted for mid-June and the average peak over the years has been about mag 7.7.<\/p>\n

By late May, however, T UMa was already around a magnitude brighter than this and so similar in brightness to comparison stars E and F.<\/p>\n

The accompanying finder chart shows the location of T UMa. The chart is approx 7 degrees by 4 degrees and has north at the top.<\/p>\n

The star Delta UMa can be a good starting point when locating T UMa.<\/p>\n

 <\/p>\n

More information about these and other Mira type variables can be found via the section’s\u00a0\u00a0Observing Programme Listing. Clicking on the name of a star in this listing takes you to a guide to that star.<\/p>\n

 <\/p>\n

… and soon to come is the maximum of\u00a0R Bootis<\/strong>, predicted for early July.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Four of the Mira type variable stars on the section’s programme – T Cep, R Ser, R UMa and T UMa – are currently near maximum and readily visible in binoculars.<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-2379","post","type-post","status-publish","format-standard","hentry","category-variable-stars"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t