Mission Blake 827
Luvah Data

Last update: 17 December 1997

Gigantic Light: The Mystery Unfolds

Luvah is perhaps the most mysterious of the Blake planets. It lies at the limit of the habitable zone at 4.5 AU, and might be either terrestrial or Jovian in nature. The nature of Luvah will depend upon what gases can be retained in its atmosphere, which is competition between temperature and gravity. The Gigantic Light flyby measured an albedo of A=0.35 for Luvah.

Questions:

  1. What is the expected surface temperature T for Luvah, as a function of the greenhouse factor G?
  2. What is the mean temperature at the top of the Luvah cloud deck?
  3. Which of these temperatures do we use in the calculation for retention of gases?

Livingstone I: Luvah, I presume ...

The Livingstone I mission carried a high-resolution imager, magnetometer, and atmospheric drop probe to Luvah.


Luvah and Rahab from Livingstone I.

Luvah clearly has an extended atmosphere, as well as a surface. From a distance of 100,000 km, Luvah subtends an angular diameter of 8° 21' 6". In this close orbit, the irregular inner satellite Rahab was spotted with an orbital period of 6 hours 49 min 46 seconds and semi-major axis of 21135 km.


Close-up of Rahab.

Questions:

  1. What is the radius of Luvah?
  2. What is the mass and mean density of Luvah?
  3. What gases could be retained in Luvah's atmosphere?
  4. From examination of the above image, what might be construed about either the tilt of Luvah's axis or the inclination of Rahab's orbital plane?

GLIP-iSOLSSAMA: I spy with my eye ...

The GLIP-iSOLSSAMA mission consists of an orbiter and series of small atmospheric drop probes. Both its probes and that of Livingstone I were successfully deployed, and the data is currently being analyzed.


Tirzah, Rahab and Luvah from GLIP-etc.

The GLIP mission found a second moon of Luvah, named Tirzah, which orbits at a radius of 147,270 km. This moon has a reddish color similar to that of Mars, as well as peculiar surface markings. Tirzah has an equatorial radius of 1620 km. The imaging spectrometer shows an average albedo of A=0.40 for Tirzah, with spectral features indicative of water ice.

Questions:

  1. What is the expected mean temperature of Tirzah?
  2. What is the likely overall composition of the surface of Tirzah? The interior?
  3. What is the period of Tirzah's orbit?
  4. The large satellites of Jupiter show spectacular cratering because of the high orbital velocities. What is the orbital velocity of Tirzah? Compare Tirzah to Ganymede.

Atmosphere of Luvah - Lighter than Air!

All three missions to Luvah carried atmospheric probes. In particluar, Livingstone I and Gigantic Light carried composition analysis packages, which were able to determine that the primary constituent of Luvah's atmosphere was helium!

The GLIP mission dropped a series of atmospheric mini-probes which were able to map out the temperature, wind, and pressure patterns over the globe of this strange planet. Wind velocities were uncommonly high, with speeds up to 100 km/hr typical. The surface pressure was found to be on the order of 0.5 bar.

Questions:

  1. Is a helium atmosphere on Luvah consistent with our above calculations?
  2. Why might the wind speeds be so high?
  3. What is the scale height in Luvah's atmosphere?

smyers@nrao.edu   Steven T. Myers