Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



EXO WORLDS
Timing the shadow of a potentially habitable extrasolar planet
by Staff Writers
Tokyo, Japan (SPX) Nov 29, 2016


This collage summarizes the research. Using the Okayama 188-cm Reflector Telescope and the observational instrument MuSCAT (See real photo on the bottom left.), researchers succeeded in observing the extrasolar planet K2-3d, which is about the same size and temperature as the Earth, pass in front of its host, the primary star blocking some of the light coming from the star (See artistic visualization at the top.), making it appear to dim (See real data on the bottom right.). Image courtesy NAOJ. For a larger version of this image please go here.

A group of researchers from the National Astronomical Observatory of Japan (NAOJ), the University of Tokyo, and the Astrobiology Center among others has observed the transit of a potentially Earth-like extrasolar planet known as K2-3d using the MuSCAT instrument on the Okayama Astrophysical Observatory 188-cm telescope.

A transit is a phenomenon in which a planet passes in front of its parent star, blocking a small amount of light from the star, like a shadow of the planet. While transits have previously been observed for thousands of other extrasolar planets, K2-3d is important because there is a possibility that it might harbor extraterrestrial life.

By observing its transit precisely using the next generation of telescopes, such as TMT, scientists expect to be able to search the atmosphere of the planet for molecules related to life, such as oxygen.

With only the previous space telescope observations, however, researchers can't calculate the orbital period of the planet precisely, which makes predicting the exact times of future transits more difficult.

This research group has succeeded in measuring the orbital period of the planet with a high precision of about 18 seconds. This greatly improved the forecast accuracy for future transit times. So now researchers will know exactly when to watch for the transits using the next generation of telescopes. This research result is an important step towards the search for extraterrestrial life in the future.

K2-3d
K2-3d is an extrasolar planet about 150 light-years away that was discovered by the NASA K2 mission (the Kepler telescope's "second light")). K2-3d's size is 1.5 times the size of the Earth. The planet orbits its host star, which is half the size of the Sun, with a period of about 45 days. Compared to the Earth, the planet orbits close to its host star (about 1/5 of the Earth-Sun distance).

But, because the temperature of the host star is lower than that of the Sun, calculations show that this is the right distance for the planet to have a relatively warm climate like the Earth's. There is a possibility that liquid water could exist on the surface of the planet, raising the tantalizing possibility of extraterrestrial life.

K2-3d's orbit is aligned so that as seen from Earth, it transits (passes in front of) its host star. This causes, short, periodic decreases in the star's brightness, as the planet blocks some of the star's light. This alignment enables researchers to probe the atmospheric composition of these planets by precise measurement of the amount of blocked starlight at different wavelengths.

About 30 potentially habitable planets that also have transiting orbits were discovered by the NASA Kepler mission, but most of these planets orbit fainter, more distant stars. Because it is closer to Earth and its host star is brighter, K2-3d is a more interesting candidate for detailed follow-up studies.

The brightness decrease of the host star caused by the transit of K2-3d is small, only 0.07%. However, it is expected that the next generation of large telescopes will be able to measure how this brightness decrease varies with wavelength, enabling investigations of the composition of the planet's atmosphere. If extraterrestrial life exists on K2-3d, scientists hope to be able to detect molecules related to it, such as oxygen, in the atmosphere.

MuSCAT Observations and Transit Ephemeris Improvements
The orbital period of K2-3d is about 45 days. Since the K2 mission's survey period is only 80 days for each area of sky, researchers could only measure two transits in the K2 data. This isn't sufficient to measure the planet's orbital period precisely, so when researchers attempt to predict the times of future transits, creating something called a "transit ephemeris," there are uncertainties in the predicted times.

These uncertainties grow larger as they try to predict farther into the future. Therefore, early additional transit observations and adjustments to the ephemeris were required before researchers lost track of the transit. Because of the importance of K2-3d, the Spitzer Space Telescope observed two transits soon after the planet's discovery, bringing the total to four transit measurements. However, the addition of even a single transit measurement farther in the future can help to yield a significantly improved ephemeris.

Using the Okayama 188-cm Reflector Telescope and the latest observational instrument MuSCAT, the team observed a transit of K2-3d for the first time with a ground based telescope. Though a 0.07% brightness decrease is near the limit of what can be observed with ground based telescopes, MuSCAT's ability to observe three wavelength bands simultaneously enhanced its ability to detect the transit.

By reanalyzing the data from K2 and Spitzer in combination with this new observation, researchers have greatly improved the precision of the ephemeris, determining the orbital period of the planet to within about 18 seconds (1/30 of the original uncertainty). This improved transit ephemeris (Figure 3) ensures that when the next generation of large telescopes come online, they will know exactly when to watch for transits. Thus these research results help pave the way for future extraterrestrial life surveys.

Future Work
The NASA K2 mission will continue until at least February 2018, and is expected to discover more potentially habitable planets like K2-3d. Furthermore, K2's successor, the Transiting Exoplanet Survey Satellite (TESS), will be launched in December 2017. TESS will survey the whole sky for two years, and is expected to detect hundreds of small planets like K2-3d near our Solar System.

To characterize a 'Second Earth' using the next generation of large telescopes, it will be important to measure the ephemerides and characteristics of planets with additional transit observations using medium sized ground-based telescopes. The team will continue using MuSCAT for research related to the future search for extraterrestrial life.

Research paper


Comment on this article using your Disqus, Facebook, Google or Twitter login.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
National Institutes of Natural Sciences
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
EXO WORLDS
Scientists from the IAC discover a nearby 'superearth'
Santa Cruz de Tenerife, Spain (SPX) Nov 17, 2016
The PhD student Alejandro Suarez Mascareno, of the Instituto de Astrofisica de Canarias (IAC) and the University of La Laguna (ULL), and his thesis directors at the IAC Rafael Rebolo and Jonay Isai Gonzalez Hernandez have discovered a "superearth" type planet, GJ 536 b, whose mass is around 5.4 Earth masses, in orbit around a nearby very bright star. The study has been accepted for publica ... read more


EXO WORLDS
Embry-Riddle Students Join Project PoSSUM to Test Prototype Spacesuits in Zero-G

NASA on the hunt for space poop geniuses

Orion Crew Module Adapter Lifted in Processing Facility at NASA's Kennedy Space Center

Expandable Habitat Reveals Important Early Performance Data

EXO WORLDS
Ariane 5's impressive 75 in-a-row launch record

Vega ready for GOKTURK-1A to be encapsulated

Star One D1 arrives for heavy-lift Ariane 5 in Dec with 2 SSL-built satellites

SLS propulsion system goes into Marshall stand ahead of big test series

EXO WORLDS
ExoMars space programme needs an extra 400 million euros

Opportunity team onsidering a new route due to boulder field

Mars Ice Deposit Holds as Much Water as Lake Superior

Computer glitch blamed for European Mars lander crash

EXO WORLDS
China launches 4th data relay satellite

Material and plant samples retrieved from space experiments

Chinese astronauts return to earth after longest mission

China completes longest manned space mission yet

EXO WORLDS
Two-year extensions confirmed for ESA's science missions

Vita: next Space Station mission name and logo

Charyk helped chart the course of satellite communications

Intelsat and Intelsat General support hurricane Matthew recovery efforts

EXO WORLDS
Bringing silicon to life

British Scientists Develop a 3D Metal Printer That Works in Space

With new polymer, you can carry hydrogen in your pocket

Scientists shrink electron gun to matchbox size

EXO WORLDS
Scientists from the IAC discover a nearby 'superearth'

Earth-bound instrument analyzes light from planets circling distant stars

Protoplanetary Discs Being Shaped by Newborn Planets

Scientists unveil latest exoplanet-hunter CHARIS

EXO WORLDS
New analysis adds to support for a subsurface ocean on Pluto

Pluto follows its cold, cold heart

New Analysis Supports Subsurface Ocean on Pluto

Mystery solved behind birth of Saturn's rings




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement