Analysis of a Newly Identified Variable Star In Aquarius

Heath Gibson

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After calculating the magnitude of variable N in each image, I plotted this against the Julian time at which it was exposed, deriving a light curve. Table 6 contains the data used to plot the light curves for variable candidate N in figures 4 and 5.

After graphing the first light curve (Figure 4), I observed a noticeable bulge at the bottom of the minimum in the sinusoidal curve. Upon closer inspection, it appeared that there were two minima graphed into the same minimum‹the first minimum seemed to reach its nadir five hundredths of a magnitude higher than the second. In order to test this theory, I doubled the period of the curve to see if the two minima could be separated from each other (the original period was 0.15315 days; doubled, it became 0.3063 days) in a new curve (Figure 5). Although there were not enough data points to fill in the part of the curve in phase 0.6 to 0.7, the necessary information to make an educated guess on the variabležs type was present. On the new light curve, there could be seen two distinct minima separated by half a phase; this indicated that the actual period was 0.3063 days. I determined that between the first and second minimum there was a magnitude difference of 0.04, while the magnitude of the variable at each maximum remained constant.

This light curve suggested a contact binary system‹due to its very short period‹with two stars of roughly the same magnitude. With the help of my mentors, I learned that this eclipsing binary (EB) had properties very similar to a W Urase Majoris (W UMa) EB. Using the Caltech library, I found the light curve of a W UMa-type system located in RZ Tauri and found the curve and period to be almost identical to mine. Like my variable, the W UMa had a short period of seven to eight hours; my variable had a period of 0.3063 days, while RZ Tauri had a period of 0.362 days. The light curves were also very similar, as can be observed in Figures 5 and 6. Figure 5, my light curve, has a difference of 0.04 magnitudes between the first and second minima; the W UMa RZ Tauri EBžs magnitude difference between minima is 0.05. The similarity between these two variables show a considerable possibility that variable N is indeed a W UMa type binary system

Table 6.  Table of magnitudes and times for variable star N as graphed in Figure 5 

Julian Day

R

Regular

Phase

Phase

2450000+

 

Phase

Repeat

Repeat

 

 

 

Add 1

Subtract 1

 

 

 

 

 

1475.6504

13.52

0.2551

1.2551

-0.7449

1475.6535

13.47

0.2450

1.2450

-0.7550

1475.6562

13.58

0.2362

1.2362

-0.7638

1475.6593

13.51

0.2261

1.2261

-0.7739

1475.6619

13.53

0.2176

1.2176

-0.7824

1475.6646

13.54

0.2088

1.2088

-0.7912

1475.6672

13.62

0.2003

1.2003

-0.7997

1475.6698

13.55

0.1918

1.1918

-0.8082

1475.6723

13.59

0.1836

1.1836

-0.8164

1475.6748

13.59

0.1755

1.1755

-0.8245

1475.6775

13.61

0.1667

1.1667

-0.8333

1475.6806

13.61

0.1566

1.1566

-0.8435

1475.6832

13.61

0.1481

1.1481

-0.8519

1475.6857

13.69

0.1399

1.1399

-0.8601

1475.6885

13.65

0.1308

1.1308

-0.8693

1475.6910

13.64

0.1226

1.1226

-0.8774

1475.6936

13.53

0.1141

1.1141

-0.8859

1475.6973

13.71

0.1020

1.1020

-0.8980

1475.6998

13.73

0.0939

1.0939

-0.9061

1475.7023

13.78

0.0857

1.0857

-0.9143

1475.7048

13.74

0.0775

1.0775

-0.9225

1475.7075

13.86

0.0687

1.0687

-0.9313

1475.7100

13.89

0.0606

1.0606

-0.9394

1475.7126

13.93

0.0521

1.0521

-0.9479

1475.7151

13.97

0.0439

1.0439

-0.9561

1475.7176

14.03

0.0358

1.0358

-0.9643

1475.7201

14.08

0.0276

1.0276

-0.9724

1475.7230

14.04

0.0181

1.0181

-0.9819

1475.7255

14.07

0.0100

1.0100

-0.9900

1475.7281

14.11

0.0015

1.0015

-0.9985

1475.7356

14.07

-0.0230

0.9770

-1.0230

1475.7382

14.01

-0.0315

0.9685

-1.0315

1475.7407

13.96

-0.0397

0.9603

-1.0397

1475.7433

13.93

-0.0482

0.9518

-1.0482

1475.7458

13.87

-0.0563

0.9437

-1.0563

1475.7511

13.80

-0.0736

0.9264

-1.0736

1475.7536

13.72

-0.0818

0.9182

-1.0818

1475.7585

13.70

-0.0978

0.9022

-1.0978

1475.7686

13.63

-0.1308

0.8693

-1.1308

1475.7711

13.60

-0.1389

0.8611

-1.1389

1475.7736

13.64

-0.1471

0.8529

-1.1471

1475.7763

13.60

-0.1559

0.8441

-1.1559

1475.7788

13.59

-0.1641

0.8360

-1.1641

1475.7813

13.55

-0.1722

0.8278

-1.1722

1475.7841

13.58

-0.1814

0.8186

-1.1814

1475.7865

13.56

-0.1892

0.8108

-1.1892

1475.7890

13.55

-0.1974

0.8026

-1.1974

1475.7918

13.64

-0.2065

0.7935

-1.2065

1475.7943

13.59

-0.2147

0.7853

-1.2147

1475.7969

13.54

-0.2232

0.7769

-1.2232

1475.7993

13.53

-0.2310

0.7690

-1.2310

1475.8018

13.55

-0.2391

0.7609

-1.2391

1475.8043

13.53

-0.2473

0.7527

-1.2473

1476.6259

13.83

0.5704

1.5704

-0.4296

1476.6292

13.84

0.5596

1.5596

-0.4404

1476.6319

13.92

0.5508

1.5508

-0.4492

1476.6346

13.98

0.5420

1.5420

-0.4581

1476.6372

14.02

0.5335

1.5335

-0.4665

1476.6397

14.06

0.5253

1.5253

-0.4747

1476.6427

14.10

0.5155

1.5155

-0.4845

1476.6454

14.11

0.5067

1.5067

-0.4933

1476.6482

14.14

0.4976

1.4976

-0.5025

1476.6508

14.13

0.4891

1.4891

-0.5109

1476.6534

14.10

0.4806

1.4806

-0.5194

1476.6561

14.12

0.4718

1.4718

-0.5282

1476.6586

14.04

0.4636

1.4636

-0.5364

1476.6610

13.99

0.4558

1.4558

-0.5442

1476.6635

13.93

0.4476

1.4476

-0.5524

1476.6661

13.86

0.4391

1.4391

-0.5609

1476.6686

13.88

0.4310

1.4310

-0.5691

1476.6711

13.83

0.4228

1.4228

-0.5772

1476.6736

13.83

0.4146

1.4146

-0.5854

1476.6773

13.76

0.4026

1.4026

-0.5975

1476.6798

13.73

0.3944

1.3944

-0.6056

1476.6823

13.73

0.3862

1.3862

-0.6138

1476.6847

13.69

0.3784

1.3784

-0.6216

1476.6993

13.59

0.3307

1.3307

-0.6693

1476.7018

13.59

0.3226

1.3226

-0.6774

1476.7045

13.59

0.3137

1.3137

-0.6863

1476.7067

13.58

0.3066

1.3066

-0.6934

1476.7095

13.57

0.2974

1.2974

-0.7026

1476.7122

13.57

0.2886

1.2886

-0.7114

1476.7147

13.55

0.2804

1.2804

-0.7196

1476.7172

13.57

0.2723

1.2723

-0.7277

1476.7197

13.53

0.2641

1.2641

-0.7359

1476.7227

13.57

0.2543

1.2543

-0.7457

1476.7254

13.55

0.2455

1.2455

-0.7545

1476.7282

13.55

0.2364

1.2364

-0.7636