stars with large amplitudes Evgeni Semkov 1 , Stoyanka Peneva 1 , - - PowerPoint PPT Presentation

Long term photometry of UXor stars with large amplitudes

Evgeni Semkov1, Stoyanka Peneva1, Sunay Ibryamov2, Asen Mutafov1

1 Institute of Astronomy and Natonal Astronomical Observatory,

Bulgarian Academy of Sciences, Sofia, Bulgaria

2 Department of Physics and Astronomy, University of Shumen, Shumen,

Bulgaria

Second International Workshop “The UX Ori type stars and related topics”

• St. Petersburg, 30 September - 4 October 2019

V1184 Tau (CB 34 V)

Discovered by Yun, Moreira, Alves, and Strom (1997) in the region of Bok globule CB 34. POSS1 POSS2

Spectral Observations of V1184 Tau

Optical spectrum of V1184 Tau obtained on 24 March 2001.

I-light curve of V1184 Tau

52000 52500 53000 53500 54000 54500 55000 55500 56000 56500 57000 57500 58000 58500 JD 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 12 13 14 15 16 17 18 I

V1184 Tau

2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8

V-I

15.0 16.0 17.0 18.0 19.0 20.0

V

0.8 1.0 1.2 1.4 1.6 1.8 2.0

R-I

14.0 15.0 16.0 17.0 18.0 19.0

R

Color indices V−I versus the stellar magnitude V and V−R versus R. The black diamonds denote observations from Oct. 2000 to Apr. 2003 (maximum level of brightness), the green diamonds observations from Aug. 2003 to Mar. 2010 (when the brightness of the star dropped) and the pink diamonds from Aug. 2010 to Apr.

• 2015. the star increased).

Long term B,R-light curves of V1184 Tau

JD (24...) Magnitude 28000 32000 36000 40000 44000 48000 52000 56000 1940 1950 1960 1970 1980 1990 2000 2010 2020 14 15 16 17 18 19 20 21 R B/pg

V350 Cep

Discovered by Gyulbudaghian & Sarkissian (1977) in the region of NGC 7129. Observed outburst 5m in R POSS1 POSS2

V350 Cep

Optical spectrum of V350 Cep

UBVRI optical photometry of V350 Cep

49000 50000 51000 52000 53000 54000 55000 56000 57000 58000 59000 JD (24...) 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 13 14 15 16 17 18 19 20 Magnitudes

I R V B U+1.5

V350 Cep

57300 57400 57500 57600 57700

JD (24...)

14 15 16 17 18 19

Magnitudes

I R V B U+1.5

UBVRI- -light curves of V350 Cep in the period August 2015 - November 2016

V350 Cep

1.6 2.0 2.4 2.8 V-I 15.5 16.0 16.5 17.0 17.5 18.0 V 0.4 0.8 1.2 1.6 V-R 15.5 16.0 16.5 17.0 17.5 18.0 V 0.8 1.2 1.6 B-V 15.5 16.0 16.5 17.0 17.5 18.0 V

Color indices V−I, V−R, and B−V versus the stellar V magnitude of V350 Cep.

Long term B-light curve of V350 Cep

35000 37500 40000 42500 45000 47500 50000 52500 55000 57500 JD (24...) 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 16 17 18 19 20 21 B/pg [mag]

Star forming region Northern America/Pelican nebulae

V521 Cyg (LkHa 188)

46500 48000 49500 51000 52500 54000 55500 57000 58500 J.D. (24...) 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 2016 2019 11 12 13 14 15 16 17 18 19 Magnitudes

I R+0.5 V+1.0 B+1.5

V521 Cyg was discovered and the star was classified as a RW Aurigae type by Hoffmeister 1949. Herbig & Bell 1988 classified it as T Tauri star with spectral type G8. Grankin et al. 2007 conduct the long-term photometric monitoring providing light curves of V521 Cyg from 1986 to 2003.

Thanks for your attention!