UV Leonis / UV Leo
The following light curve and phase diagram were constructed from photometry of 212 unfiltered images taken with the Bradford Robotic Telescope Cluster Camera between 2013 May 26 and 2015 June 24.
(The minima are the correct way round; the primary minimum was not as well covered as the secondary minimum.)
The following light curves were constructed from photometry of unfiltered images taken with the 2" Titan (2 inch Titan) at Somerby Observatory.
Coming out of a primary minimum
A primary minimum
A primary minimum
Coming out of a primary minimum
A secondary minimum
A secondary minimum
A primary minimum
A secondary minimum
Using all the above observations, the following light curve and phase diagram were constructed.
The 2021 observations on their own for clarity
The following phase diagram was constructed from all the above observations with the exception of those on 2021 March 29, which were compromised by the proximity of the bright Moon.
Notes
The catalogue values for the period are 0.60008478d ref GCVS and 0.60008731d ref AAVSO VSX.
(Accessed 2021 April 21)
This star has o-c interest (Kreiner) and evidence of surface activity, see e.g. Manzoori 2012.
(Accessed 2021 April 21)
This star has o-c interest (Kreiner) and evidence of surface activity, see e.g. Manzoori 2012.
Binary Maker 3 model
The following is a model binary system which fits the above observations, using Binary Maker 3 (BM3). It uses no other observations and does not include any radial velocity data (which I could not find) so it is not a 'definitive' model by any means.
In this model the primary has a mass of 1.13 solar masses and a surface temperature of 5 960 K while the secondary has a mass of 1.08 solar masses and a surface temperature of 5 790 K. The inclination of the perpendicular to the plane of the orbits to our line of sight is 83.3 degrees.
This results in the following light curve, in blue, compared to my observations.
In this model the primary has a mass of 1.13 solar masses and a surface temperature of 5 960 K while the secondary has a mass of 1.08 solar masses and a surface temperature of 5 790 K. The inclination of the perpendicular to the plane of the orbits to our line of sight is 83.3 degrees.
This results in the following light curve, in blue, compared to my observations.
View along our line of sight. The red area is a starspot. See eg Conroy et al (2010) regarding more modelling of UV Leonis star spots.
View of system from perpendicular above the plane of the orbits
Some significant gravitational potentials.
Output from Binary Maker
mass ratio input = 0.965000 mass ratio < 1 = 0.965000
Omega 1 = 4.453567 Omega 2 = 4.399998
Omega inner = 3.692900 Omega outer = 3.165508
C 1 = 4.774066 C 2 = 4.719543
C inner = 3.999851 C outer = 3.463064
Fillout 1 = -0.162171 Fillout 2 = -0.152492
Lagrangian L1 = 0.503667 Lagrangian L2 = 1.692574
AG = r1(back) = 0.300000 AS = r2(back) = 0.299162
BG = r1(side) = 0.290359 BS = r2(side) = 0.288942
CG = r1(pole) = 0.283672 CS = r2(pole) = 0.282158
DG = r1(point) = 0.306178 DS = r2(point) = 0.305770
Surface area 1 = 1.069629 Surface area 2 = 1.060598
Volume 1 = 0.103135 Volume 2 = 0.101822
Mean radius 1 = 0.291344 Mean radius 2 = 0.290087
Mean radius 1 (vol) = 0.290919 Mean radius 2 (vol) = 0.289679
Eccentricity = 0.00000 Longitude of Periastron = 0.0000
Phase of periastron = 0.00000 Phase of conjunction = 0.00000
Angular Rotation F1 = 1.0000 Angular Rotation F2 = 1.0000
Normalization Phase = 0.25000 Normalization Factor = 0.95200
inclination = 83.300 wavelength = 5500.00
temperature 1 = 5960.00 temperature 2 = 5790.00
luminosity 1 = 0.5411 luminosity 2 = 0.4589
gravity coefficient 1 = 0.320 gravity coefficient 2 = 0.320
limb darkening 1 = 0.540 limb darkening 2 = 0.550
reflection 1 = 0.560 reflection 2 = 0.560
Third light = 0.0000 Period = 0.60008668
K1 = 159.700000 K2 = 166.500000
V0 = -13.300000
Absolute Parameters
-------------------
Mass 1 = 1.128477 solar masses Mass 2 = 1.082389 solar masses
Semi-major axis = 2.710047 million km Semi-major axis = 3.893745 solar radii
Mean radius 1 = 0.789555 million km Mean radius 1 = 1.134418 solar radii
Mean radius 2 = 0.786150 million km Mean radius 2 = 1.129525 solar radii
Mean density 1 = 1.093981 grams/cm^3 Mean density 2 = 1.062837 grams/cm^3
Output from Binary Maker
mass ratio input = 0.965000 mass ratio < 1 = 0.965000
Omega 1 = 4.453567 Omega 2 = 4.399998
Omega inner = 3.692900 Omega outer = 3.165508
C 1 = 4.774066 C 2 = 4.719543
C inner = 3.999851 C outer = 3.463064
Fillout 1 = -0.162171 Fillout 2 = -0.152492
Lagrangian L1 = 0.503667 Lagrangian L2 = 1.692574
AG = r1(back) = 0.300000 AS = r2(back) = 0.299162
BG = r1(side) = 0.290359 BS = r2(side) = 0.288942
CG = r1(pole) = 0.283672 CS = r2(pole) = 0.282158
DG = r1(point) = 0.306178 DS = r2(point) = 0.305770
Surface area 1 = 1.069629 Surface area 2 = 1.060598
Volume 1 = 0.103135 Volume 2 = 0.101822
Mean radius 1 = 0.291344 Mean radius 2 = 0.290087
Mean radius 1 (vol) = 0.290919 Mean radius 2 (vol) = 0.289679
Eccentricity = 0.00000 Longitude of Periastron = 0.0000
Phase of periastron = 0.00000 Phase of conjunction = 0.00000
Angular Rotation F1 = 1.0000 Angular Rotation F2 = 1.0000
Normalization Phase = 0.25000 Normalization Factor = 0.95200
inclination = 83.300 wavelength = 5500.00
temperature 1 = 5960.00 temperature 2 = 5790.00
luminosity 1 = 0.5411 luminosity 2 = 0.4589
gravity coefficient 1 = 0.320 gravity coefficient 2 = 0.320
limb darkening 1 = 0.540 limb darkening 2 = 0.550
reflection 1 = 0.560 reflection 2 = 0.560
Third light = 0.0000 Period = 0.60008668
K1 = 159.700000 K2 = 166.500000
V0 = -13.300000
Absolute Parameters
-------------------
Mass 1 = 1.128477 solar masses Mass 2 = 1.082389 solar masses
Semi-major axis = 2.710047 million km Semi-major axis = 3.893745 solar radii
Mean radius 1 = 0.789555 million km Mean radius 1 = 1.134418 solar radii
Mean radius 2 = 0.786150 million km Mean radius 2 = 1.129525 solar radii
Mean density 1 = 1.093981 grams/cm^3 Mean density 2 = 1.062837 grams/cm^3
[ This page updated 2022 October 29 ]