Unusual team finds gigantic planet hidden in plain sight
Gas giant is much closer to Earth than others like it

Date:
January 13, 2022
Source:
University of California - Riverside
Summary:
An astronomer and a group of eagle-eyed citizen scientists
have discovered a giant gas planet hidden from view by typical
stargazing tools.



FULL STORY ==========================================================================
A UC Riverside astronomer and a group of eagle-eyed citizen scientists
have discovered a giant gas planet hidden from view by typical stargazing tools.


==========================================================================
The planet, TOI-2180 b, has the same diameter as Jupiter, but is nearly
three times more massive. Researchers also believe it contains 105 times
the mass of Earth in elements heavier than helium and hydrogen. Nothing
quite like it exists in our solar system.

Details of the finding have been published in the Astronomical Journaland presented at the American Astronomical Society virtual press event on
Jan. 13.

"TOI-2180 b is such an exciting planet to have found," said UCR astronomer
Paul Dalba, who helped confirm the planet's existence. "It hits the
trifecta of 1) having a several-hundred-day orbit, 2) being relatively
close to Earth (379 lightyears is considered close for an exoplanet),
and 3) us being able to see it transit in front of its star. It is
very rare for astronomers to discover a planet that checks all three of
these boxes." Dalba also explained that the planet is special because it
takes 261 days to complete a journey around its star, a relatively long
time compared to many known gas giants outside our solar system. Its
relative proximity to Earth and the brightness of the star it orbits
also make it likely astronomers will be able to learn more about it.

In order to locate exoplanets, which orbit stars other than our sun,
NASA's TESS satellite looks at one part of the sky for a month, then
moves on. It is searching for dips in brightness that occur when a planet crosses in front of a star.



==========================================================================
"The rule of thumb is that we need to see three 'dips' or transits before
we believe we've found a planet," Dalba said. A single transit event
could be caused by a telescope with a jitter, or a star masquerading as
a planet. For these reasons, TESS isn't focused on these single transit
events. However, a small group of citizen scientists is.

Looking over TESS data, Tom Jacobs, a group member and former U.S. naval officer, saw light dim from the TOI-2180 star, just once. His group
alerted Dalba, who specializes in studying planets that take a long time
to orbit their stars.

Using the Lick Observatory's Automated Planet Finder Telescope, Dalba
and his colleagues observed the planet's gravitational tug on the star,
which allowed them to calculate the mass of TOI-2180 b and estimate a
range of possibilities for its orbit.

Hoping to observe a second transit event, Dalba organized a campaign
using 14 different telescopes across three continents in the northern hemisphere. Over the course of 11 days in August 2021, the effort resulted
in 20,000 images of the TOI-2180 star, though none of them detected the
planet with confidence.

However, the campaign did lead the group to estimate that TESS will see
the planet transit its star again in February, when they're planning
a follow up study. Funding for Dalba's research is provided by the
National Science Foundation's Astronomy and Astrophysics Postdoctoral Fellowship Program.

The citizen planet hunters' group takes publicly available data from
NASA satellites like TESS and looks for single transit events. While professional astronomers use algorithms to scan a lot of data
automatically, the Visual Survey Group uses a program they created to
inspect telescope data by eye.

"The effort they put in is really important and impressive, because it's
hard to write code that can identify single transit events reliably,"
Dalba said.

"This is one area where humans are still beating code." ========================================================================== Story Source: Materials provided by
University_of_California_-_Riverside. Original written by Jules
Bernstein. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Paul A. Dalba, Stephen R. Kane, Diana Dragomir, Steven Villanueva,
Karen
A. Collins, Thomas Lee Jacobs, Daryll M. LaCourse, Robert Gagliano,
Martti H. Kristiansen, Mark Omohundro, Hans M. Schwengeler, Ivan A.

Terentev, Andrew Vanderburg, Benjamin Fulton, Howard Isaacson,
Judah Van Zandt, Andrew W. Howard, Daniel P. Thorngren, Steve
B. Howell, Natalie M.

Batalha, Ashley Chontos, Ian J. M. Crossfield, Courtney D. Dressing,
Daniel Huber, Erik A. Petigura, Paul Robertson, Arpita Roy,
Lauren M.

Weiss, Aida Behmard, Corey Beard, Casey L. Brinkman, Steven
Giacalone, Michelle L. Hill, Jack Lubin, Andrew W. Mayo, Teo
Močnik, Joseph M.

Akana Murphy, Alex S. Polanski, Malena Rice, Lee J. Rosenthal,
Ryan A.

Rubenzahl, Nicholas Scarsdale, Emma V. Turtelboom, Dakotah
Tyler, Paul Benni, Pat Boyce, Thomas M. Esposito, E. Girardin,
Didier Laloum, Pablo Lewin, Christopher R. Mann, Franck Marchis,
Richard P. Schwarz, Gregor Srdoc, Jana Steuer, Thirupathi Sivarani,
Athira Unni, Nora L. Eisner, Tara Fetherolf, Zhexing Li, Xinyu Yao,
Joshua Pepper, George R. Ricker, Roland Vanderspek, David W. Latham,
S. Seager, Joshua N. Winn, Jon M.

Jenkins, Christopher J. Burke, Jason D. Eastman, Michael B. Lund,
David R. Rodriguez, Pamela Rowden, Eric B. Ting, Jesus Noel
Villasen~or. The TESS-Keck Survey. VIII. Confirmation of a
Transiting Giant Planet on an Eccentric 261 Day Orbit with the
Automated Planet Finder Telescope*. The Astronomical Journal,
2022; 163 (2): 61 DOI: 10.3847/1538-3881/ac415b ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220113194141.htm
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