(Candidate LBV) Some overlap with stars about 2 magnitudes fainter 3--7 arcseconds away. Most easily resolved in R and I. B on 2457035.63981 flagged as “X” for bad PSF fit due to bad seeing. **Updated 180521**

MJD | V | * | Image | B | * | Image | R | * | Images | I | * | Images |
---|---|---|---|---|---|---|---|---|---|---|---|---|

56140.40 | 16.94± 0.05 | b | -- | - | - | 16.84± 0.06 | b | -- | - | - | ||

56599.22 | 17.01± 0.06 | b | 17.27± 0.05 | b | 16.79± 0.05 | b | -- | - | - | |||

57035.14 | 16.82± 0.04 | b | 17.46± 0.05 | X | 16.69± 0.05 | b | -- | - | - | |||

57310.16 | 16.99± 0.05 | b | 17.19± 0.05 | b | 16.81± 0.05 | b | -- | - | - | |||

57328.16 | 17.03± 0.03 | b | 17.09± 0.04 | b | 16.83± 0.04 | b | -- | - | - | |||

57406.10 | 16.82± 0.04 | b | 16.80± 0.04 | b | 16.77± 0.05 | b | 16.62± 0.07 | b | ||||

57634.39 | 16.93± 0.06 | Ab | 17.23± 0.08 | Ab | 16.73± 0.07 | Ab | -- | - | - | |||

57638.40 | 16.97± 0.05 | Ab | 17.01± 0.04 | b | 16.81± 0.03 | b | 16.66± 0.08 | Ab | ||||

57964.40 | 16.94± 0.04 | b | -- | - | - | -- | - | - | 16.56± 0.07 | Ab | ||

57988.43 | 16.90± 0.06 | Tb | -- | - | - | -- | - | - | -- | - | - | |

58043.13 | 17.16± 0.05 | b | 17.09± 0.04 | b | 16.88± 0.04 | b | -- | - | - | |||

58073.22 | 16.95± 0.05 | b | 17.19± 0.05 | b | -- | - | - | -- | - | - | ||

58108.13 | 16.99± 0.04 | Ab | 17.06± 0.05 | Ab | -- | - | - | 16.54± 0.08 | Ab | |||

58316.35 | 17.12± 0.07 | b | 17.20± 0.04 | b | -- | - | - | -- | - | - | ||

58339.40 | 16.92± 0.05 | b | 16.96± 0.06 | b | 16.73± 0.06 | b | -- | - | - | |||

58341.37 | 16.97± 0.04 | b | -- | - | - | -- | - | - | 16.64± 0.08 | b | ||

58373.15 | 17.03± 0.06 | b | 17.15± 0.06 | b | -- | - | - | -- | - | - | ||

58433.02 | 17.04± 0.05 | b | -- | - | - | 16.87± 0.05 | b | 16.53± 0.09 | b | |||

58673.38 | 17.01± 0.03 | b | 17.13± 0.03 | b | -- | - | - | -- | - | - | ||

58695.39 | 17.01± 0.05 | b | -- | - | - | 16.84± 0.04 | b | -- | - | - | ||

58750.20 | 16.96± 0.04 | Ab | 17.07± 0.03 | b | 16.74± 0.05 | b | 16.65± 0.08 | b | ||||

58779.18 | 16.84± 0.04 | b | 17.09± 0.06 | b | -- | - | - | -- | - | - | ||

58784.14 | 17.00± 0.04 | b | -- | - | - | 16.79± 0.04 | b | -- | - | - | ||

58812.20 | 17.02± 0.06 | b | -- | - | - | 16.81± 0.07 | b | -- | - | - | ||

59059.40 | 17.02± 0.06 | b | -- | - | - | 16.82± 0.05 | b | 16.63± 0.08 | b | |||

59081.34 | 16.98± 0.06 | Ab | 17.04± 0.06 | Ab | 16.77± 0.05 | Ab | 16.55± 0.07 | b | ||||

59082.38 | 16.95± 0.05 | b | 16.95± 0.03 | b | 16.76± 0.04 | b | -- | - | - | |||

59084.25 | -- | - | - | -- | - | - | 16.73± 0.04 | Tb | -- | - | - | |

59161.14 | 17.02± 0.05 | b | -- | - | - | 16.89± 0.04 | b | 16.74± 0.10 | b | |||

59171.15 | 17.00± 0.05 | Ab | 17.21± 0.11 | Ab | 16.82± 0.05 | b | 16.65± 0.08 | Ab | ||||

59227.14 | 17.04± 0.05 | Ab | 17.08± 0.05 | Ab | 16.86± 0.05 | Ab | 16.70± 0.08 | b |

From the data available in this survey, it is not possible to tell with certainty if this star is variable.

If the brightness variation is true variability then there should be a correlation between brightness changes recorded in different filter bands. The following table are the R-squared linear correlation factors calculated for the pairs of bands. The number in parentheses next to the R-squared value is the number of elements used to calculate the correlation factor. The number in square brackets next to the band is the range of magnitudes measured.

V [0.47 mag] | B [0.35 mag] | R [0.20 mag] | |
---|---|---|---|

B [0.47 mag] | 0.20 (19) | ||

R [0.20 mag] | 0.62 (21) | 0.05 (13) | |

I [0.21 mag] | 0.02 (12) | 0.04 (7) | 0.14 (9) |

The plots below are provided to check the values in the table above and also to show any non-linear correlations

Welch & Stetson (1993, AJ, 105, 1813) present a method for varible star detection in CCD images from automated surveys. Data from two bands are compared and two statistics are calculated: R and I.

The I-statistic has an expectation value of zero for stars that are NOT variable. A larger non-zero I-value indicates a higher likelihood that the star is variable. The R statistic indicates how the color of the star changes as the variable grows brighter with R = 1.0 being no change in color.

R and I values have only been calculated if there are more than four (4) matched measurements of brightness in each band.

V (I|R) | B (I|R) | R (I|R) | |
---|---|---|---|

B (I|R) | 2.36 | 1.57 | ||

R (I|R) | 1.46 | 1.30 | -1.01 | 0.42 | |

I (I|R) | 0.12 | 1.29 | 0.28 | 3.22 | 0.29 | 1.43 |

By John C. Martin, University of Illinois Springfield Henry R. Barber Research Observatory

*Generated on 2021-11-06 16:53:54 UT-5*