Astronomers have recently discovered a new strange rocky Exoplanet in a triple star system. Our sun is the only star in our solar system, but out in the wider universe stars often are locked in a dance with other stars and orbit at a mutual centre of gravity.
A catchy name was allotted, LTT 1445Ab since it orbits the primary star of the three red dwarfs of system LTT 1445, located around 22.5 light-years away from earth. Astronomer Jennifer Winters of the Harvard-Smithsonian Center said that on standing on that planet’s surface, there will be three suns in the sky with two of them far away and small in size. The paper is submitted to The Astronomical Journal and can found on arXiv.
The planet was discovered by TESS, the planet-hunting space telescope of NASA which is designed to find exoplanets that pass between us and their home star by detecting the telltale dimming since the planet blocks a certain percentage of light. Scientists can place constraints on mass and size of the planet due to the depth of dimming, tiny star movements since it is slightly pulled by the gravity of planet.
The LTT 1445Ab varies from the HD131399Ab which was discovered back in 2016. It was bigger with a 550-year orbit around one of the star in a triple system 340 light-years away from earth. The new planet is only 1.35 times the size of Earth and 8.4 times Earth’s mass and thus is denser than Earth.
The size and mass put it in the category of rocky planets like Mars, Venus etc. and is not a gas or ice giant. The chances of habitability are low. The surface temperature is expected to reach scorching 428 Kelvin and it whips around its star once every 5.36 Earth days.
Astronomers predict that LTT 1445Ab might have an atmosphere like any other rocky planet and might be a good place to test the detection of gases like methane and carbon dioxide. The atmosphere dims the starlight and can also change it based on chemical composition. The atmospheric components can be found out based on the spectrum of light through the atmosphere.
The current technology is not well developed for this task but may become possible with the Hubble’s successor, the James Webb Space Telescope which will launch in 2021. LTT 1445Ab is a good candidate for observations as there will be plenty of observations and is relatively very close in a cosmic scale at a distance of 22.5 light-years away. The dwarf star is bright enough to back-light the atmosphere but not bright enough to outshine the planet. Rocky planets are relatively common in the close orbits around red dwarf stars. Hence, looking at the LTT1445Ab closer can tell us what to expect on such planets.
Journal Reference: arXiv