Variables: SALC 34 North

An important task is to identify all variable stars that can become as bright as the stars at the limit of the binocular limiting magnitude (BLM). For the Fujinon 10x70's this is currently ~9.4+. Searching at the BLM takes some effort so I've chosen an effective BLM (eBLM) of mag. 9.0.

For this purpose I set up an Excel file back in December of 2004 to filter on all known variables. This file contains all the stars in the General Catalog of Variable Stars (GCVS) which numbered 63,265 stars at the time. The filesize is ~37 megabytes.

The outline of the 'search area location chart' (SALC), in Right Ascension (RA) and Declination (Dec), is entered including a buffer zone. The buffer zone should include all stars in asterisms that extend beyond the boundaries of the main search area. This zone varies for each SALC.

SALC 34 (North) in Perseus:
• RA: +03h 50m - +30h 00m (buffer: 00h 07m)
• Dec: +50° - +45° (buffer: +01° 30')

This file identifies all variables in the SALC/buffer zone allowing one to filter on stars in any of the following categories:

• Spans - Stars that span the eBLM and change brightness by at least 3 tenths of a magnitude. These stars will become dimmer and grow brighter than the eBLM. These can easily be confused for a novae without knowing them beforehand. Four stars fall into this category for SALC 34N. See below for details. [Each variable has hyperlinks to two on-line catalogs. The 1st hyperlink after 'Name:' accesses SIMBAD & the last hyperlink accesses the GCVS.]

• Br.>.3 - Stars that change brightness by at least 3 tenths of a magnitude and are listed as always brighter than the eBLM. Four stars fall into this category. Only one, LX Per (8.1 - 8.9) comes close to the eBLM. See details below.

• Dim>.3 - Stars that change brightness by at least three tenths of a magnitude and are listed as always dimmer than the eBLM but no dimmer than three tenths of the eBLM. One star, NSV 15688, falls into this category ranging from 9.1 - 10.3 mag. See below for details.

Historic Novae (SALC 34 complete):

NOVA Persei 1901, GK Persei, [1] [2] - mv 0.2 - 14
RA 3h31m12s / Dec +43°54'15"
From Burnham's Celestial Handbook by R. Burnham Jr.

“Nova Persei 1901. About 4.5° NE of Algol. The first bright nova of the 20th Century, first noticed on February 21, 1901, by the amateur astronomer T.D. Anderson of Edinburgh, Scotland. At that time the star was of the 2nd magnitude, but within 2 days it had increased its light more than 6 times, and attained its maximum brilliancy of magnitude 0.2 on February 23.”

• SEARCH: AAVSO - charts, VSoM, publ. | ADS | Google | wiki.

NOVA Persei 1974, V400 Persei, [1] [2] - mv 8 - 18.26
RA 3h7m38s / Dec +47°7'40"
From “The UK Nova/Supernova Patrol—The First 25 Years” by Guy M. Hurst, 15 April 2000

“However in 1974, a nova was found in Perseus by N. Sanduleak and announced on IAU Circular No. 2716, and later designated V400 Persei. Although the nova had already faded to magnitude 11 by the time it was found on an objective prism plate of November 9, 1974, there was a possibility that it had been brighter at an earlier date and been missed.”

• SEARCH: AAVSO - charts | ADS | Google

Variable Stars (eBLM set to 9.0):

Span's eBLM (Range > mv 0.3):

Name: Y Persei, HD 21280, HIP 16126
RA / Dec: 03h 27m 42.39s / +44° 10' 36.5"
Magnitude, Max. - Min.: 8.1 - 11.3
Type / Period: Mira / 248.6 days
Spectrum: C4,3e(R4e)
• SEARCH: AAVSO - charts | ADS | Google

Name: V410 Persei, HD 19881, HIP 15026
RA / Dec: 03h 13m 38.65s / +47° 49' 33.9"
Magnitude, Max. - Min.: 8.8 - 9.4
Type / Period: SRB: (Semiregular late-type) / 110 days
Spectrum: C7,4(Np)

Name: NSV 15682, TYC 3320-1183-1, BD +48 0908
RA / Dec: 03h 25m 13.8s / +49° 10' 04"
Magnitude, Max. - Min.: 8.4 - 9.6
Type / Period: E: (Eclipsing Binary) / no period listed
Spectrum: K2

Name: NSV 15684, TYC 3316-1812-1, BD +47 0819
RA / Dec: 03h 25m 29.5s / +47° 58' 03"
Magnitude, Max. - Min.: 8.5 - 10.0
Type / Period: Flare on Jan. 9, 1992 / no period listed
Spectrum: A5V

Brighter than eBLM (Range > mv 0.3):

Name: LX Per, TYC 3315-1535-1, HIP 15003
RA / Dec: 03h 13m 22.37s / +48° 06' 31.3"
Magnitude, Max. - Min.: 8.1 - 8.93
Type / Period: EA/AR/RS / 8.038207 days
Spectrum: G5IV+G5IV

Name: V572 Per, HD 20096, HIP 15193
RA / Dec: 03h 15m 48.68s / +50° 57' 21.2"
Magnitude, Max. - Min.: 6.5 - 6.79
Type / Period: EA / no period listed
Spectrum: A0

Name: NSV 15601, HD 17891, HIP 13512
RA / Dec: 02h 54m 00.98s / +47° 09' 39.2"
Magnitude, Max. - Min.: 6.78 - < 7.5
Type / Period: VAR: / no period listed
Spectrum: B9

Name: NSV 15600, HD 17818, HIP 13462
RA / Dec: 02h 53m 21.07s / +48° 34' 11.8"
Magnitude, Max. - Min.: 6.17 - 6.55
Type / Period: VAR: / no period listed
Spectrum: G5Iab:

Dimmer than eBLM (Range > mv 0.3):

Name: NSV 15688, TYC 2873-716-1, BD +43 0719
RA / Dec: 03h 26m 52.72s / +44° 21' 50.7"
Magnitude, Max. - Min.: 9.1 - 10.3
Type / Period: no details listed
Spectrum: K0