V455And

Dwarf Nova HS 2331+3905 (V455 And)

Observation of Dwarf Nova HS 2331+3905 (V455 And) at Kobdilj Observatory (Sep. 7 - Oct. 8, 2007)

The WZ Sge candidate V455 And went into its first observed outburst on 2007 September 4, brightening from quiescent magnitude 16 to visual magnitude 13.9 on Sep. 4.8431 UT, and continued to brighten to a maximum of ~8.6 on September 6 (AAVSO Alert 357). The V455 And is located at R.A. = 23h34m01.55s, Decl. = 39° 21' 42.9" (equinox 2000.0). We observed the star on 15 nights, beginning on Sept. 7, until Oct. 8, 2007. The Period determination of V455 And was analysed only for first 10 nights (from Sept. 7 to Sept. 21, 2007). The observations were made remotely (except 14th and 15th) with 25cm, f/4 LX200 telescope, ST-7 CCD and standard V photometric filter. All exposures lasted for 80 second. Altogether we collected 2855 data points (our statistics). All data was sent to AAVSO and VSNET.

V455 And Identification Image
CCD field of V455 And and surrounding stars. Images were dark, bias subtracted and flat corrected. Copyright © 2007 by T. Fabjan and M. Mihelčič, Kobdilj Observatory.

The V455 And Outburst and Decline During the 14 day Observing Period
We fitted our 10 sets of observations with second order polynomial in first step of period determination. Copyright © 2007 by T. Fabjan, M. Mihelčič and N. Štritof, Kobdilj Observatory.

V455 And O-C Diagram
Observed minus above mentioned fitted polynomial decay diagram (O-C) of V455 And was done in second step of period determination. Copyright © 2007 by T. Fabjan, M. Mihelčič and N. Štritof, Kobdilj Observatory.

V455 And Period Determination
(O-C) diagram processed with Lomb-Scargle Method with Peranso. Strongest signal has period P = 0.0578 +/-0.0001 d and Theta = 121.52. This is the last step of period determination. Period determination by N. Štritof. Copyright © 2007 by T. Fabjan, M. Mihelčič and N. Štritof, Kobdilj Observatory.

Further Analysis of V455 And Period with Phase Diagram
All 1553 observations (first 10 nights) folded by above mentioned period of P = 0.0578 d. Note that this is probably a hump period. Also note that orbital period of P(orb) = 0.0563 d mantioned in AAVSO alert has much weaker power Theta = aprox. 47.0! Copyright © 2007 by T. Fabjan, M. Mihelčič and N. Štritof, Kobdilj Observatory.

The V455 And Outburst and Decline
The light curve of dwarf nova V455 And during the Sept.-Oct. 2007 outburst. Altogether we collected 2855 measurements, covering the period Sept. 7 to Oct. 8, 2007. Copyright © 2007 by T. Fabjan and M. Mihelčič, Kobdilj Observatory.

Daily Light Curves of V455 And

Date	Measurements	Filter	Data	Light Curve 1	Light Curve 2
7./8. Sept. 2007	62	V
9./10. Sept. 2007	178	V
12./13. Sept. 2007	115	V
13./14. Sept. 2007	133	V
14./15. Sept. 2007	88	V
15./16. Sept. 2007	171	V
16./17. Sept. 2007	34	V
19./20. Sept. 2007	300	V
20./21. Sept. 2007	290	V
21./22. Sept. 2007	182	V
29./30. Sept. 2007	284	V
30. Sept. /1. Oct. 2007	309	V
1./2. Oct. 2007	300	V
7./8. Oct. 2007	248	V
8./9. Oct. 2007	161	V