New Jupiter-sized exoplanet discovered with TESS
New Jupiter-sized exoplanet discovered with TESS
Time series of RV observations of TOI-3757 with HPF (green) and NEID (red). The best-fitting model derived from the joint fit to the photometry and RVs is plotted in blue, including the 16-84 percent confidence interval in lighter blue. The bottom panel shows the residuals after subtracting the model. Credit: Kanodia et al., 2022.
Using NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers from the Pennsylvania State University (PSU) and elsewhere have detected a new Jupiter-sized extrasolar world. The newfound exoplanet, designated TOI-3757 b, is slightly larger than Jupiter but more than three times less massive than the solar system’s biggest planet. The finding is reported in a paper published March 15 on arXiv.org.
TESS is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. It has identified over 5,400 candidate exoplanets (TESS Objects of Interest, or TOI), of which 199 have been confirmed so far.
A group of astronomers led by PSU’s Shubham Kanodia has recently confirmed another TOI monitored by TESS. They report that a transit signal has been identified in the light curve of an M dwarf star known as TOI-3757. The planetary nature of this signal was confirmed by follow-up observations.
“We present the discovery and confirmation of TOI-3757 b, a Jovian sized planet, characterized using a combination of space based photometry from TESS, precise RVs [radial velocities] from HPF [Habitable-zone Planet Finder] and NEID [NN-explore Exoplanet Investigations with Doppler spectroscopy], ground based photometric observations from RBO [Red Buttes Observatory], and speckle imaging from NESSI [NN-Explore Exoplanet Stellar Speckle Imager],” the researchers wrote in the paper.
TOI-3757 b has a radius of about 1.09 Jupiter radii, while its mass is approximately 0.268 Jupiter masses. This yields a density of only 0.27 g/cm3, what makes it the lowest density planet orbiting an M dwarf known to date. The exoplanet orbits its host every 3.44 days, at a distance of some 0.038 AU from it. The equilibrium temperature of this alien world is estimated to be 759 K.
Located around 578 light years away from the Earth, the parent star TOI-3757 is an M dwarf of spectral type M0V, about 37 percent smaller and less massive than the sun. The star has a solar metallicity, is estimated to be 7.1 billion years old, and its effective temperature is at a level of 3,913 K. It was noted that TOI-3757 has the lowest stellar metallicity of all M dwarfs hosting gas giants.
Trying to explain the low density of TOI-3757 b, the authors of the paper offer two most plausible hypotheses. They assume that that low metallicity of the M dwarf could be responsible for the delayed on-set of gaseous runaway accretion before the protoplanetary disk dissipated or that it could be a result of an evolution mechanisms where the tidal heating causes the inflation of the planet due to its slightly eccentric orbit.
The researchers added that the second scenario could be verified by measuring the levels of methane and ammonia. Such study would help constrain the interior temperature of TOI-3757, which can provide insight into potential tidal heating.
Speed of Light Could Be Dropped to Zero Using Crystals
In a vacuum like space, the speed of light is just over 186,280 miles per second. Scientists have now shown it’s possible to slow it down to zero miles per second without sacrificing its brightness, regardless of its frequency or bandwidth.
A team of researchers from the Israel Institute of Technology and the Institute of Pure and Applied Mathematics in Brazil discovered a method of theoretically bringing the speed of light to a halt by capitalizing on “exceptional points”—coordinates at which two separate light emissions reach each other and merge into a single one, according to Phys.org. A paper describing the research was published in the scientific journal Physical Review Letters.
Slow-light technologies could help improve our telecommunications systems, as well as our quantum computers. Existing research shows us that light can be slowed to an infinitesimal fraction of its vacuum speed in two ways, according to the new paper: trapping it inside either ultracold atom clouds or inside waveguides made with photonic crystals.
The first involves aiming a laser into a cloud of ultracold sodium atoms, the researchers wrote in their paper. When the laser is abruptly switched off, a slow pulse of light is imprinted onto the atoms, essentially bringing the light to a halt by absorbing it; the imprinted shape can then be converted back into a photon. But it’s the second method that allowed the researchers to make their breakthrough.
Photonic crystals are materials perforated with billions of tiny holes through which light refracts, according to Reader’s Digest. A waveguide, meanwhile, is a confining tube-like structure, which, as the name suggests, guides the waves sent inside it (any kind of waves, but in this case optical waves).
The problem is that the process of slowing down light tends to sap its intensity. What the team discovered is that such losses can be eliminated if a waveguide is designed with parity-time symmetry, a relatively new concept that refers to maintaining a constant balance, or symmetry, between a system’s energy losses and gains.
Parity-symmetric waveguides can keep the light’s intensity steady and symmetric as it arrives at an exceptional point, the place where two incoming sources merge into a single pathway. Which means that now we could not only stop the light and hold it there, but release it and ramp it back up to its regular speed without ever losing any of its intensity—a level of consistency and control not offered through previous models.
By tweaking the gain-loss parameters, the technique could be adapted to light of any and all frequencies and bandwidths, making it much more versatile than other light-stopping methods scientists have created in the past, according to Phys.org. The researchers believe the system could work for not just light, but other kinds of waves like sound. https://www.thespaceacademy.org/2021/12/speed-of-light-could-be-dropped-to-zero.html?m=1&fbclid=IwAR0jjOiyesI4YvaxXjr3V5tmO_o6ZHqH26z6yjk4VHSVdIExXIGarix6MTg