Hubble Finds Star Eating a Planet

[caption id="attachment_625" align="alignleft" width="400" caption="This is an artist's concept of the exoplanet WASP-12b. It is the hottest known planet in the Milky Way galaxy, and potentially the shortest lived. The planet is only 2 million miles from its sunlike parent star — a fraction of Earth's distance from the Sun. Gravitational tidal forces from the star stretch the planet into an egg shape. The planet is so hot that it has puffed up to the point where its outer atmosphere spills onto the star. An accretion bridge streams toward the star and material is smeared into a swirling disk. The planet may be completely devoured by the star in 10 million years. The planet is too far away for the Hubble Space Telescope to photograph, but this interpretation is based in part on analysis of Hubble spectroscopic and photometric data."][/caption]

The hottest known planet in the Milky Way galaxy may also be its shortest-lived world. The doomed planet is being eaten by its parent star, according to observations made by a new instrument on  Hubble Space Telescope, the Cosmic Origins Spectrograph (COS). The planet may only have another 10 million years left before it is completely devoured.

The planet, called WASP-12b, is so close to its sunlike star that it is superheated to nearly 2,800 degrees Fahrenheit and stretched into a football shape by enormous tidal forces. The atmosphere has ballooned to nearly three times Jupiter's radius and is spilling material onto the star. The planet is 40 percent more massive than Jupiter.

This effect of matter exchange between two stellar objects is commonly seen in close binary star systems, but this is the first time it has been seen so clearly for a planet.

A theoretical paper published in the science journal Nature last February by Shu-lin Li of the Department of Astronomy at the Peking University, Beijing, first predicted that the planet's surface would be distorted by the star's gravity, and that gravitational tidal forces make the interior so hot that it greatly expands the planet's outer atmosphere. Now Hubble has confirmed this prediction.

WASP-12 is a yellow dwarf star located approximately 600 light-years away in the winter constellation Auriga. The exoplanet was discovered by the United Kingdom's Wide Area Search for Planets (WASP) in 2008. The automated survey looks for the periodic dimming of stars from planets passing in front of them, an effect called transiting. The hot planet is so close to the star it completes an orbit in 1.1 days.

The unprecedented ultraviolet (UV) sensitivity of COS enabled measurements of the dimming of the parent star's light as the planet passed in front of the star. These UV spectral observations showed that absorption lines from aluminum, tin, manganese, among other elements, became more pronounced as the planet transited the star, meaning that these elements exist in the planet's atmosphere as well as the star's. The fact the COS could detect these features on a planet offers strong evidence that the planet's atmosphere is greatly extended because it is so hot.

The UV spectroscopy was also used to calculate a light curve to precisely show just how much of the star's light is blocked out during transit. The depth of the light curve allowed the COS team to accurately calculate the planet's radius. They found that the UV-absorbing exosphere is much more extended than that of a normal planet that is 1.4 times Jupiter's mass. It is so extended that the planet's radius exceeds its Roche lobe, the gravitational boundary beyond which material would be lost forever from the planet's atmosphere.

Hubble Site News center/AASTRO

Positions of Project Assistants for Astronomy Olympiad

Homi Bhabha Centre for Science Education at Tata institute of fundamental Research  (TIFR), Mumbai hereby invites applicants for Walk-in-interview for two Positions of Project Assistants for Astronomy Olympiad, to work at HBCSE.


Nature of Job :

  • Project Assistant (First Position) : The candidate will be responsible for academic support for the Astronomy Olympiad activities.This includes helping in question paper setting at each level of the Olympiad, managing communication with the international committee, sending regular study material to the students etc.

  • Project Assistant (Second Position) : The candidate will be responsible for research & referencing for creating popular astronomy books , typesetting the same in Marathi & participate in Astronomy Olympiad & “Yes! You can do it” activities.

Desired Qualification :

  • First Position : Strong interest in Astronomy, Astrophysics & night sky observation, some experience in numerical programming, experience in working on GNU/Linux platform, teaching abilities.

  • Second Position : Strong interest in Astronomy, Astrophysics & night sky observation, some experience in Marathi typesetting, teaching abilities.

Qualification & experience:. B. Sc / M. Sc. with Physics or related topic / B. Tech. in a physics related branch with at least 55% marks.

The position is purely temporary, for one year in the first instance and extendable by one or two more years. A consolidated monthly honorarium will be paid as follows.

  • For Project Assistant with Bachelor’s degree (B. Sc.) - Rs. 7,500/- during the first year, Rs. 8,500/- during the second year andRs. 9,500/- during the third year + HRA 30% in lieu of Government accommodation.

  • For Project Assistants with Master’s degree (M. Sc.) Rs. 10,000/- during the first year, Rs. 11,000/- during the second year and Rs. 12,000/- during the third year + HRA 30% in lieu of Government accommodation.

Age: Below 30 years. ( Relaxable in deserving cases)

Applicants must bring with them the following: 1) Application mentioning post applied for, Notice Number and giving full details such as Name, Date of Birth, full address with phone/mobile number and e-mail address, Educational Qualification, experience, caste, names and addresses of two referees (attach reference certificate). 2) True copies of relevant certificates with original certificates for verification and testimonials. 3) One latest photograph. 4) Applicants in Govt. / Semi-Government / Public Sector undertakings /Autonomous body must get No Objection Certificates from their reporting Officer.

Outstation candidates belonging to SC/ST are entitled for ordinary/Mail/Express second class return railway fare by shortest route only on production of railway ticket. This concession is not applicable to those SC/ST candidates who are already in Central/State Govt. service

There will be a walk in interview for the selection.

Date & Times of Interview : Tuesday, June 22 , 2010. Time : 9.00 a. m.

Venue: Homi Bhabha Centre for Science Education, T.I.F.R., (Next to Anushaktinagar Bus Terminus), V. N. Purav Marg, Mankhurd, Mumbai 400 088. To reach the Centre you may come by train to Mankhurd (Harbour Line) or take BEST Bus routes, 21 Ltd. from Dadar (E), 92 Ltd. or 521 Ltd. from Dadar (W), 360 from Kurla or 352 from Sion.

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