Institute of Astronomy

Astronomy News

First close-ups of Jupiter’s Great Red Spot from Juno flyby

13 July 2017 - 8:54am

The closest-ever observations of our solar system’s biggest storm could tell us how deep into Jupiter it extends and how it has continued to rage for centuries

NASA's SDO Watches a Sunspot Turn Toward Earth

13 July 2017 - 8:54am
Portal origin URL: NASA's SDO Watches a Sunspot Turn Toward EarthPortal origin nid: 405269Published: Wednesday, July 12, 2017 - 08:21Featured (stick to top of list): noPortal text teaser: A new sunspot group has rotated into view and seems to be growing rather quickly in this video captured by NASA's Solar Dynamics Observatory between July 5-11, 2017.Portal image: animation of SDO observations of a sunspotScience Categories: Sun

Smallest-ever star discovered by astronomers

12 July 2017 - 9:34am

The smallest star yet measured has been discovered by a team of astronomers led by the University of Cambridge. With a size just a sliver larger than that of Saturn, the gravitational pull at its stellar surface is about 300 times stronger than what humans feel on Earth.

The star is likely as small as stars can possibly become, as it has just enough mass to enable the fusion of hydrogen nuclei into helium. If it were any smaller, the pressure at the centre of the star would no longer be sufficient to enable this process to take place. Hydrogen fusion is also what powers the Sun, and scientists are attempting to replicate it as a powerful energy source here on Earth.

These very small and dim stars are also the best possible candidates for detecting Earth-sized planets which can have liquid water on their surfaces, such as TRAPPIST-1, an ultracool dwarf surrounded by seven temperate Earth-sized worlds.

The newly-measured star, called EBLM J0555-57Ab, is located about six hundred light years away. It is part of a binary system, and was identified as it passed in front of its much larger companion, a method which is usually used to detect planets, not stars. Details will be published in the journal Astronomy & Astrophysics.

“Our discovery reveals how small stars can be,” said Alexander Boetticher, the lead author of the study, and a Master’s student at Cambridge’s Cavendish Laboratory and Institute of Astronomy. “Had this star formed with only a slightly lower mass, the fusion reaction of hydrogen in its core could not be sustained, and the star would instead have transformed into a brown dwarf.”

EBLM J0555-57Ab was identified by WASP, a planet-finding experiment run by the Universities of Keele, Warwick, Leicester and St Andrews. EBLM J0555-57Ab was detected when it passed in front of, or transited, its larger parent star, forming what is called an eclipsing stellar binary system. The parent star became dimmer in a periodic fashion, the signature of an orbiting object. Thanks to this special configuration, researchers can accurately measure the mass and size of any orbiting companions, in this case a small star. The mass of EBLM J0555-57Ab was established via the Doppler, wobble method, using data from the CORALIE spectrograph.

“This star is smaller, and likely colder than many of the gas giant exoplanets that have so far been identified,” said von Boetticher. “While a fascinating feature of stellar physics, it is often harder to measure the size of such dim low-mass stars than for many of the larger planets. Thankfully, we can find these small stars with planet-hunting equipment, when they orbit a larger host star in a binary system. It might sound incredible, but finding a star can at times be harder than finding a planet.”

This newly-measured star has a mass comparable to the current estimate for TRAPPIST-1, but has a radius that is nearly 30% smaller. “The smallest stars provide optimal conditions for the discovery of Earth-like planets, and for the remote exploration of their atmospheres,” said co-author Amaury Triaud, senior researcher at Cambridge’s Institute of Astronomy. “However, before we can study planets, we absolutely need to understand their star; this is fundamental.”

Although they are the most numerous stars in the Universe, stars with sizes and masses less than 20% that of the Sun are poorly understood, since they are difficult to detect due to their small size and low brightness. The EBLM project, which identified the star in this study, aims to plug that lapse in knowledge. “Thanks to the EBLM project, we will achieve a far greater understanding of the planets orbiting the most common stars that exist, planets like those orbiting TRAPPIST-1,” said co-author Professor Didier Queloz of Cambridge’ Cavendish Laboratory.

Reference
Alexander von Boetticher et al. ‘A Saturn-size low-mass star at the hydrogen-burning limit.’ Astronomy & Astrophysics (2017). arXiv:1706.08781

A star about the size of Saturn – the smallest ever measured – has been identified by astronomers. 

Our discovery reveals how small stars can be.Alexander Boetticher


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Titan’s conditions could be just right to power US-sized colony

12 July 2017 - 9:33am

Saturn’s largest moon may be able to provide enough wind, solar or tidal power to make human life there a possibility – if we can build the tech to exploit it

HIRMES: A New High-resolution Mid-infrared Spectrometer for SOFIA

12 July 2017 - 9:30am
Cutaway CAD model representation of
proposed HIRMES instrument design.
(Credit: GSFC HIRMES Instrument Team)

Technology Development: NASA is developing a new instrument to expand the boundaries of astronomy research. A team of scientists and technologists at NASA’s Goddard Space Flight Center (GSFC) is developing the High-Resolution Mid-Infrared Spectrometer (HIRMES)—an innovative instrument that will enable new scientific investigations and important contributions to our understanding of the cosmos. HIRMES' commissioning is anticipated for late 2018 on NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA), a heavily modified Boeing 747SP that carries a 2.5m-diameter infrared telescope. SOFIA flies above ~95% of the Earth’s atmospheric water vapor, allowing astronomers to gain access to wavelengths that are not possible to observe from the ground, even with the most powerful groundbased telescopes. HIRMES applies emerging detector and optical technologies tailored to take maximum advantage of the unique platform provided by SOFIA, covering the 25–122-micron spectral range with resolving powers ranging from 600 to 100,000.

HIRMES will extend proven technologies, striking a balance between pushing the state of the art and providing reliable performance to SOFIA’s growing user community. HIRMES will employ superconducting transition edge sensor (TES)-based bolometers, operating at temperatures of ~0.1 K to provide sensitivity limited only by the intrinsic signal-to-noise ratio imposed by the sky background. These detectors promise an order of magnitude lower noise compared with the heterodyne detectors presently deployed in SOFIA instrumentation, and will decrease observing time by a factor of ~200 on spectral lines of interest. HIRMES detectors will be arrayed in a 16x64-element format to provide low- and medium-resolution spectroscopic observations, including an imaging capability. A separate 8x16-element array optimized for low backgrounds will be used for high-resolving power observations. A multi-stage refrigeration system will provide the ~100mK heat sink needed for background-limited detector performance. Optical dispersion of the light delivered by the telescope will be accomplished via a system of gratings, mirrors, and tunable Fabry-Perot interferometric monochromators.

HIRMES on SOFIA will probe the structure and evolution of protoplanetary disks and
increase our ability to model these systems as they evolve to fledgling planetary
systems. (Credit: GSFC HIRMES Instrument Team)

 

Impact: HIRMES’ prime investigation is a detailed study of the processes leading to the formation of planetary systems over a spectral range rich in ionic, atomic, and molecular lines. The HIRMES science program will determine the structure and evolution of protoplanetary disks and will increase our ability to model these systems as they evolve from homogeneous disks to fledgling planetary systems. At the beginning of their lives, stars significantly interact with their environments and the HIRMES program will advance our understanding about the ways these interactions regulate star formation. The HIRMES team will also study the formation processes of massive protostars and the mechanisms that accelerate dust in asymptotic giant branch (AGB) stars. NASA anticipates significant demand within the scientific community for the powerful new capabilities that HIRMES will provide.

Status and Future Plans: The GSFC team developed an instrument concept study in 2016, leading to the competitive selection of HIRMES for development. Work began immediately on development of the instrument, including laboratory evaluation of brassboard subsystems and procurement of limited long-lead hardware items to support an aggressive development schedule. The HIRMES team is working toward a critical design review in FY17, followed by hardware development to enable instrument delivery in late 2018.

Sponsoring Organization: HIRMES development is sponsored by the SMD Astrophysics Division in conjunction with the SOFIA Program Office. Dr. Harvey Moseley is the HIRMES Principal Investigator (PI), with GSFC as the lead NASA Center for HIRMES development. SOFIA is managed by NASA’s Ames Research Center and operated out of NASA’s Armstrong Flight Research Center in Palmdale, California.

Master Image: 

Australia Enters Strategic Partnership with ESO

12 July 2017 - 9:30am
At a ceremony today in Canberra, Australia, an arrangement was signed to begin a ten-year strategic partnership between ESO and Australia. The partnership will further strengthen ESO’s programme, both scientifically and technically, and will give Australian astronomers and industry access to the La Silla Paranal Observatory. It may also be the first step towards Australia becoming an ESO Member State.

Eighth Call for PROBA2 Guest Investigator Program

12 July 2017 - 9:29am
The Royal Observatory of Belgium invites research proposals from potential Guest Investigators for the analysis of data from PROBA2's two solar observation instruments, SWAP and LYRA. Early-career post-docs and PhD students are particularly invited to apply, although proposals from more senior Guest Investigators are also encouraged. Proposals in response to this Call must be received by 24 September 2017, 23:59 CEST (21:59 UTC).

Galaxy Zoo: Citizen science trailblazer marks tenth birthday

12 July 2017 - 9:28am

Galaxy Zoo is one of the most successful citizen science projects ever conceived. We look back at what it's achieved over 10 years.

Preparing for Mercury: BepiColombo stack completes testing

7 July 2017 - 9:19am

ESA's Mercury spacecraft has passed its final test in launch configuration, the last time it will be stacked like this before being reassembled at the launch site next year.

Mercury mission: BepiColombo gets ready to launch

7 July 2017 - 9:18am

A mission to Mercury is getting closer to the launch pad.

Pulsars still dazzle after 50 years

6 July 2017 - 9:32am
The Universe’s flash machines have proven their scientific value.

Dazzling Spiral with an Active Heart

6 July 2017 - 9:26am
ESO’s Very Large Telescope (VLT) has captured a magnificent face-on view of the barred spiral galaxy Messier 77. The image does justice to the galaxy’s beauty, showcasing its glittering arms criss-crossed with dust lanes — but it fails to betray Messier 77’s turbulent nature.

BepiColombo: Joint Mercury mission ready for 'pizza oven'

6 July 2017 - 9:25am

Europe and Japan say their joint space mission is ready to face the inferno of working at Mercury.

UK research chief 'will not direct science'

4 July 2017 - 1:08pm

The new head of UK research has said that he won't centrally direct scientific research.

Our young moon’s supersonic winds made waves in its magma ocean

4 July 2017 - 9:22am

Just after it was formed, the moon’s magma ocean would have steamed out a sodium atmosphere on the hot, Earth-facing side, creating dramatic winds

Protons are lighter than thought, which may solve a big puzzle

4 July 2017 - 9:21am

A new experiment that makes the proton 30 billionths of a per cent lighter than before could help make sense of the glut of matter over antimatter in the cosmos

Demise of dinosaurs opened the doors to the age of tree frogs

4 July 2017 - 9:21am

Frogs leaped to take advantage of the global catastrophe that killed off the dinosaurs 66 million years ago

Ribbiting stuff

4 July 2017 - 9:20am

The huge diversity of frogs we see today is mainly a consequence of the asteroid strike that killed off the dinosaurs, a study suggests.

Sun’s gravity could power interstellar video streaming

3 July 2017 - 9:17am

Space transmissions could slingshot around the sun for a signal boost, producing data rates fast enough to stream video from interstellar space

Hawking says Trump's climate stance could damage Earth

3 July 2017 - 9:16am

Stephen Hawking warns over Donald Trump's climate policy in a BBC interview marking his 75th birthday.