December 2nd 2021

Calar Alto Observatory and the Institute of Astrophysics of Andalusia (IAA-CSIC) participate in the study of the giant planets of the V1298 Tauri system, which in just twenty million years have already reached their final size: a contraction time much shorter than expected. The finding has been possible thanks, in particular, to radial velocity measurements from the HARPS-N spectrographs, at Roque de los Muchachos Observatory (ORM), and from CARMENES, at Calar Alto Observatory (CAHA)

Current theories of planetary evolution predict that giant planets, such as Jupiter or Saturn, are born with large dimensions and very low densities and that, after hundreds of millions of years of slow contraction, they reach their final size. However, these expectations do not have corroborating evidence, and a recent finding shows that they may not correspond to reality in some cases. An international scientific team has measured the mass of the planets of the V1298 Tauri system, one of the youngest known, and concludes that the giant planets could complete their contraction much faster than expected. The result is published in the journal Nature Astronomy.

November 23rd 2021

Pointing the Schmidt telescope at Calar Alto, a volunteer scientist observing for the European Space Agency has discovered a new type of cataclysmic variable star, the first eclipsing stream-fed intermediate polar binary star. In this kind of “violent couple”, one of the stars (the white dwarf) pulls out matter from its partner (the red dwarf) towards its magnetic poles in huge streams of gas and dust.

Using the Calar Alto Schmidt telescope as part of the Space Situational Awareness Program of the European Space Agency (ESA), Erwin Schwab, an amateur astronomer and volunteer scientist for ESA, was searching for the lost comet P/2012 K3 (Gibbs). In the night from July 26 to 27, 2019, he took series of images from the predicted position in the constellation Sagittarius. The comet was not there… Yet, during the data inspection, Schwab noticed a star in the field, which suddenly disappeared from one picture to the next.  The faint variable object was cataloged as J1832.4-1627 from its coordinates on the sky. After further observing nights with the Schmidt and other telescopes, he was able to detect several deep eclipses of the star, which occurred every 9 hours or so.

September 24th 2021

The planet Venus is permanently covered by high clouds that extend over a thick atmosphere that hide from direct view the hottest planetary surface (about 460°C) in the Solar System. Three Calar Alto telescopes participate in an ambitious campaign of Venus observations combining data from different space missions and ground-based telescopes to understand Venus’ cloud layers and possible changes in the planet’s brightness. The first results of this campaign are presented these days at the Europlanet Science Congress.

Venus is the planet that has the closest approach to Earth, but its surface remains invisible, fully hidden by thick layers of clouds that reflect most of the sunlight making Venus the brightest planet as observed from Earth. Despite being so close and bright, Venus holds several mysteries in its atmosphere and its surface. One of the most recently discovered is the changes in the global brightness of the upper clouds detected when comparing images of Venus obtained on different years. What causes those changes, and what is their impact in the atmosphere and surface are still largely unknown.