Key link found in Cosmic Distance Ladder

Jun 20, 2013
Key link found in Cosmic Distance Ladder

(Phys.org) —When observing the bright explosion of a White Dwarf star in our neighbouring galaxy last year, researchers from The Australian National University collected the largest ever data set on what they recognised as one of our best 'standard candles' yet for distance measurements in the Universe.

"We know how a candle of a particular brightness grows fainter as it is moved further away from us. So, if we know the true brightness of the candle (in this instance, supernova SN 2012fr) and we measure its observed brightness, we can then calculate the interceding distance," said Dr Michael Childress.

Supernova SN 2012fr left a which has been analysed by a team of researchers led by Dr Childress from the ANU Research School of and which also includes Professor Brian Schmidt.

Their data shows unprecedented, and quite unusual, layering in the material that was burnt and ejected in the explosion, especially silicon and iron.

Two distinct layers of silicon were found: one thick, outer layer that had faded by the time the supernova reached its peak brightness on 12 November 2012 (16 days after the initial explosion), and one deeper layer that hardly changed for several weeks after the explosion.

"As it turns out, SN 2012fr is not just another supernova but a really interesting case. Since it was discovered within a day of explosion, we were able to study it in greater detail than almost any supernova ever discovered," Dr Childress said.

"Because we know the distance to its (NGC 1365), this supernova actually lets us better calibrate all Type Ia Supernova observations to measure distances in the Universe, using what we call the 'standard candle' technique.

This video is not supported by your browser at this time.
A short research presentation by Dr Childress.

Despite its unusual layers, SN 2012fr appears to still be classified as a so-called 'normal' Type Ia Supernova – which Professor Schmidt used in his winning work to discover Dark Energy – and it also presents a key link in our cosmic distance ladder.

"Our analyses of SN 2012fr will increase the precision of which we can measure distances outside of our own galaxy, as well as improve our understanding of these explosive events and our ability to use them in the hunt for Dark Energy, the source of the accelerated expansion of the Universe," said Dr Childress.

This research is part of 'The Dark Universe' theme of the ARC Centre of Excellence for All-sky Astrophysics, CAASTRO (www.caastro.org) and is published today in The Astrophysical Journal.

Explore further: Satellite galaxies put astronomers in a spin

Related Stories

Astronomers discover light echo from supernova

Jun 04, 2013

(Phys.org) —Astronomers have discovered light echoing off material surrounding a recent supernova explosion, SN 2009ig. The dust and gas that are reflecting the light are so close to the eruption center ...

Spiral beauty graced by fading supernova

Mar 20, 2013

(Phys.org) —About 35 million light-years from Earth, in the constellation of Eridanus (The River), lies the spiral galaxy NGC 1637. Back in 1999 the serene appearance of this galaxy was shattered by the ...

Hubble telescope breaks record for farthest supernova

Apr 04, 2013

(Phys.org) —The supernova, designated SN UDS10Wil, belongs to a special class of exploding stars known as Type Ia supernovae. These bright beacons are prized by astronomers because they can be used as a ...

Recommended for you

Satellite galaxies put astronomers in a spin

15 hours ago

An international team of researchers, led by astronomers at the Observatoire Astronomique de Strasbourg (CNRS/Université de Strasbourg), has studied 380 galaxies and shown that their small satellite galaxies almost always ...

Video: The diversity of habitable zones and the planets

15 hours ago

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable ...

Ultra-deep astrophoto of the Antenna Galaxies

15 hours ago

You might think the image above of the famous Antenna Galaxies was taken by a large ground-based or even a space telescope. Think again. Amateur astronomer Rolf Wahl Olsen from New Zealand compiled a total ...

The most precise measurement of an alien world's size

17 hours ago

Thanks to NASA's Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement ever of the radius of a planet outside our solar system. The size of the exoplanet, dubbed Kepler-93b, ...

User comments : 0