Extrasolar, Stars and Exoplanets for Celestia

[LukeCEL]

ZTF J2055+4651, only the second known binary consisting of a hot OB subdwarf and a white dwarf. Parameters from Kupfer et al. (2020).

Code: Select all

Barycenter "ZTF J2055+4651"
{
   RA 313.81658333
   Dec 46.85179444
   Distance 7502 # 2.3 kpc
}

"ZTF J2055+4651 A"
{
   OrbitBarycenter "ZTF J2055+4651"
   SpectralType "sdO"
   AbsMag 4.37 # estimate from temperature and radius
   Radius 118269
   Temperature 33700

   EllipticalOrbit {
      Period          0.000107133
      SemiMajorAxis   0.0014506 # mass ratio 0.41:0.68
      Inclination     79.97     # inclination to plane of sky:
      AscendingNode   308.45    # 83.4 deg
      ArgOfPericenter 0
   }

   UniformRotation {
      Period          0.93913083 # assuming tidal locking
      Inclination     79.97
      AscendingNode   308.45
   }
}

"ZTF J2055+4651 B"
{
   OrbitBarycenter "ZTF J2055+4651"
   SpectralType "D1" # from T = 63 kK
   AbsMag 8.88 # estimate from temperature and radius
   Radius 10297
   Temperature 63000

   EllipticalOrbit {
      Period          0.000107133
      SemiMajorAxis   0.0008746 # mass ratio 0.41:0.68
      Inclination     79.97     # inclination to plane of sky:
      AscendingNode   308.45    # 83.4 deg
      ArgOfPericenter 180
   }

   UniformRotation {
      Period          0.93913083 # assuming tidal locking
      Inclination     79.97
      AscendingNode   308.45
   }
}

[jujuapapa]

ZTF J2055+4651, only the second known binary consisting of a hot OB subdwarf and a white dwarf. Parameters from Kupfer et al. (2020).

Code: Select all

Barycenter "ZTF J2055+4651"
{
   RA 313.81658333
   Dec 46.85179444
   Distance 7502 # 2.3 kpc
}

"ZTF J2055+4651 A"
{
   OrbitBarycenter "ZTF J2055+4651"
   SpectralType "sdO"
   AbsMag 4.37 # estimate from temperature and radius
   Radius 118269
   Temperature 33700

   EllipticalOrbit {
      Period          0.000107133
      SemiMajorAxis   0.0014506 # mass ratio 0.41:0.68
      Inclination     79.97     # inclination to plane of sky:
      AscendingNode   308.45    # 83.4 deg
      ArgOfPericenter 0
   }

   UniformRotation {
      Period          0.93913083 # assuming tidal locking
      Inclination     79.97
      AscendingNode   308.45
   }
}

"ZTF J2055+4651 B"
{
   OrbitBarycenter "ZTF J2055+4651"
   SpectralType "D1" # from T = 63 kK
   AbsMag 8.88 # estimate from temperature and radius
   Radius 10297
   Temperature 63000

   EllipticalOrbit {
      Period          0.000107133
      SemiMajorAxis   0.0008746 # mass ratio 0.41:0.68
      Inclination     79.97     # inclination to plane of sky:
      AscendingNode   308.45    # 83.4 deg
      ArgOfPericenter 180
   }

   UniformRotation {
      Period          0.93913083 # assuming tidal locking
      Inclination     79.97
      AscendingNode   308.45
   }
}

Writed and tested.

This works fine...

[LukeCEL]

Here is KIC 12268220, an eclipsing binary. It looks a bit unusual, because the secondary star has a very low mass (about 0.23 Msol) while being quite large (over 3 Rsol). The paper mentioned several other similar systems, apparently the prototype is R CMa. Parameters from Cui et al. (2020).

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Barycenter 1005723569 "KOI-7518:KIC 12268220"
{
   RA 296.49067287
   Dec 50.90586057
   Distance 4372.121
}

"KOI-7518 A:KIC 12268220 A"
{
   OrbitBarycenter "KOI-7518"
   SpectralType "A7IV" # from temperature
   AbsMag 1.00 # from temperature and radius
   Radius 2247111

   EllipticalOrbit {
      Period          0.012105626
      SemiMajorAxis   0.0071307 # mass ratio 1.99:0.23
      Eccentricity    0
      Inclination     99.65
      AscendingNode   288.20
      ArgOfPericenter 162.15
   }

   UniformRotation {
      Period          106.11792 # assuming tidal locking
      Inclination     99.65
      AscendingNode   288.2
   }
}

"KOI-7518 B:KIC 12268220 B"
{
   OrbitBarycenter "KOI-7518"
   SpectralType "K4IV" # from temperature; low-mass and evolved
   AbsMag 3.74 # from temperature and radius
   Radius 2205370
   SemiAxes [ 1 0.95 1 ] # estimate

   EllipticalOrbit {
      Period          0.01210563
      SemiMajorAxis   0.0616962 # mass ratio 1.99:0.23
      Eccentricity    0
      Inclination     99.65
      AscendingNode   288.20
      ArgOfPericenter 342.15
   }

   UniformRotation {
      Period          106.11792 # assuming tidal locking
      Inclination     99.65
      AscendingNode   288.2
   }
}

[Trolligi 112477]

Weird, but very interesting.
Question: How can an orange subgiant have such a low mass? I would expect it to have a mass of between 0.6 and 2 MSol. How did it lose so much mass?

[LukeCEL]

Question: How can an orange subgiant have such a low mass? I would expect it to have a mass of between 0.6 and 2 MSol. How did it lose so much mass?

Even though the secondary star has the appropriate temperature and radius, I wouldn't really call it a "subgiant"; that's mainly for Celestia. From what I can tell in the paper, the secondary star was originally the higher-mass star, but evolved quicker and transferred its mass to the primary star. In the future, it might evolve into a EL CVn binary, which is an A- or F-type star orbiting a helium white dwarf.

[Trolligi 112477]

Ahh okay.

[LukeCEL]

Here's a very low-mass eclipsing binary. NGTS J0930-18 has an M0V star and a companion just above the hydrogen-burning limit. Parameters from Acton et al. (2020).

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Barycenter "NGTS J0930-18"
{
   RA 142.56666667
   Dec -18.84267222
   Distance 742.614
}

"NGTS J0930-18 A"
{
   OrbitBarycenter "NGTS J0930-18"
   SpectralType "M0V"
   AppMag 15.529
   Radius 406145

   EllipticalOrbit {
      Period          0.003648586
      SemiMajorAxis   0.0027074 # mass ratio M2/M1 = 0.1059
      Inclination     108.37
      AscendingNode   140.09
      ArgOfPericenter 56.37
      MeanAnomaly     270
      Epoch           2457679.29957
   }

   UniformRotation {
      Inclination     108.37
      AscendingNode   140.09
   }
}

"NGTS J0930-18 B"
{
   OrbitBarycenter "NGTS J0930-18"
   SpectralType "M8.5V" # estimate from mass, radius
   AbsMag 19.14 # estimate from mass, radius
   Radius 73675

   EllipticalOrbit {
      Period          0.003648586
      SemiMajorAxis   0.0192426 # mass ratio M2/M1 = 0.1059
      Inclination     108.37
      AscendingNode   140.09
      ArgOfPericenter 236.37
      MeanAnomaly     270
      Epoch           2457679.29957
   }

   UniformRotation {
      Inclination     108.37
      AscendingNode   140.09
   }
}

[LukeCEL]

Here's a recently-discovered triple star system. TIC 278825952 consists of three stars, two of which are similar and on a tight, nearly circular orbit, and the third, which is on an unusually circular orbit around the two. Parameters from Mitnyan et al. (2020).

Code: Select all

Barycenter "TIC 278825952"
{
   RA 100.47064
   Dec 55.79494
   Distance 1830 # 561 ± 8 pc
}

Barycenter "TIC 278825952 AB"
{
   OrbitBarycenter "TIC 278825952"

   EllipticalOrbit {
      Period          0.6449005
      SemiMajorAxis   0.2703646 # mass ratio (1.119:1.094):0.746
      Eccentricity    0.00271
      Inclination     93.78
      AscendingNode   99.41
      ArgOfPericenter 86.69
      Epoch           2458401.5712 # inferior conjunction
      MeanAnomaly     306.25
   }
}

"TIC 278825952 A"
{
   OrbitBarycenter "TIC 278825952 AB"
   SpectralType "F7V" # estimate from parameters
   AbsMag 3.71
   Radius 976067

   EllipticalOrbit {
      Period          0.013089728
      SemiMajorAxis   0.0357949 # mass ratio 1.119:1.094
      Eccentricity    0.00027
      Inclination     94.18
      AscendingNode   99.56
      ArgOfPericenter 273.7
      Epoch           2458328.94778 # inferior conjunction
      MeanAnomaly     118.97
   }
}

"TIC 278825952 B"
{
   OrbitBarycenter "TIC 278825952 AB"
   SpectralType "F7V" # estimate from parameters
   AbsMag 3.90
   Radius 908584

   EllipticalOrbit {
      Period          0.013089728
      SemiMajorAxis   0.0366129 # mass ratio 1.119:1.094
      Eccentricity    0.00027
      Inclination     94.18
      AscendingNode   99.56
      ArgOfPericenter 93.7
      Epoch           2458328.94778 # inferior conjunction
      MeanAnomaly     118.97
   }
}

"TIC 278825952 C"
{
   OrbitBarycenter "TIC 278825952"
   SpectralType "K3V"
   AbsMag 6.61
   Radius 483510

   EllipticalOrbit {
      Period          0.6449005
      SemiMajorAxis   0.8020332 # mass ratio (1.119:1.094):0.746
      Eccentricity    0.00271
      Inclination     93.78
      AscendingNode   99.41
      ArgOfPericenter 266.69
      Epoch           2458401.5712 # inferior conjunction
      MeanAnomaly     306.25
   }
}

[pedro_jg]

Greetings! Here is a small STC file for displaying the three fastest rotating brown dwarfs known, recently announced on a study by Tannock et al. They have rotation periods just above one hour and are visibly oblate, though not too much since BDs are very dense objects.

This should be compatible with SevenSpheres' brown dwarf catalog, provided that addon loads before this file.

Oblate_BDs.zip

(865 Bytes) Downloaded 253 times

[SevenSpheres]

Update to GCIRS 16SW, a contact binary star at the Galactic Center. The mesh was created using ajtribick's recent Python script, which can be found here. This addon requires Vision's Galactic Center addon, since the star is defined to orbit Sagittarius A*.

Edit: This is now included in my fixed version of Vision's addon.

gcirs_16sw.zip

(47.25 KiB) Downloaded 283 times

[ajtribick]

Thanks for test-driving the instructions!

[pedro_jg]

With NGC 3132 (Eight-Burst/Southern Ring Nebula) being one of JWST's first targets, it deserves an update in Celestia.

Model and texture can be taken from jll's add-on.

STC code:

Code: Select all

# https://www.aanda.org/articles/aa/full_html/2020/02/aa36845-19/aa36845-19.html
# Distance from http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A110
# Magnitudes from https://iopscience.iop.org/article/10.1086/300940

1009637711 "HD 87892 A"
{
   RA 151.757357
   Dec -40.436425
   Distance 2476
   SpectralType "A0V"
   AppMag 10.11
   InfoURL "http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+87892"
}

# Epoch J2000 coordinates from Gaia DR3
"HD 87892 B"
{
   RA 151.756901
   Dec -40.436745
   Distance 2476
   SpectralType "D0"  # from T_eff
   AppMag 15.76
   InfoURL "http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+87892"
}

DSC code (designations from Origin):

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Nebula "Eight-Burst Nebula:Southern Ring Nebula:NGC 3132:Caldwell 74:PK 272+12.1:ESO 316-PN27:AM 1004-401"
{
   Mesh "ngc3132-3d.3ds"
   Radius 0.56
   RA 10.1171267
   Dec -40.435
   Distance 2476
   Axis [ -0.738745 -0.222812 -0.63609 ]
   Angle 134.239
   InfoURL "https://en.wikipedia.org/wiki/NGC_3132"
}

P.S. Quite frustratingly, the newest star database files give the HD 87892 designation to an unrelated star, although this seems to stem from the Tycho-HD cross-match used, so there isn't much to be done here.