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  • richardmitnick 11:11 am on September 25, 2021 Permalink | Reply
    Tags: "The Search for Another Earth", Astronomer Sara Seager, Exoplanet Reseach,   

    From University of Toronto (CA) : “The Search for Another Earth” 

    From University of Toronto (CA)

    September 23, 2021
    Dan Falk

    Astronomer Sara Seager believes there are other planets that support life. She’s dedicated much of her career to finding them.

    A few years ago, Sara Seager (BSc 1994 UC) decided that the colourful, fantasy-travel posters published by The Jet Propulsion Laboratory [NASA] at Caltech (US) would be perfect for the hallway just outside her office in The Massachusetts Institute of Technology (US)’s department of earth, atmospheric and planetary sciences. The posters show fanciful depictions of not only the planets in our own solar system but also of far-away worlds discovered only in the last few decades. (The tag-line for Kepler 16b, a planet that orbits a double-star system: “Where your shadow always has company.”) Whether humans will ever visit these distant worlds is anybody’s guess; even travelling at the speed of light, getting to Kepler 16b would take 200 years. But to Seager, these worlds feel much closer. Astronomers have now catalogued more than 4,500 of these “exoplanets,” some of which may not be too different from our own world. The flurry of discovery has made Seager confident that life, of some sort, is likely to be found beyond our home planet.

    “We know that small, rocky exoplanets are common; we know they’re out there, and there are a lot of them,” she told me on a call from her home in Concord, Massachusetts. A photograph of the constellation Orion, the mighty hunter, hung on the Zoom background behind her.

    “We also suspect the ingredients for life – at least, life as we know it – are very common as well. And water – we think it’s very abundant. So the ingredients for life are there, and the planets are there, and really they just need to come together the right way.”

    Seager, 50, has been described by The New York Times as “the woman who might find us another Earth,” while NASA has called her “an astronomical Indiana Jones.”

    Sara Seager. Credit. Credit: Noah Kalina.

    In late 2020, Seager was appointed to the Order of Canada. She is now at the top of her field, but her journey has not been an easy one, as she recounts in her widely praised memoir, The Smallest Lights in the Universe, published last year. There has been love, and also loss, and – at the risk of giving away the book’s ending – love once again.

    Sara Seager. Photo by Tony Luong.

    Born and raised in Toronto, Seager fell in love with the stars after a camping trip to Bon Echo Provincial Park, in rural eastern Ontario. She knew about the stars from books, of course, and from visits to the McLaughlin Planetarium; and she had glimpsed them in a modest way even from light-polluted Toronto. But she had never seen them like this. “It was just so shocking to me,” she recalls. “It was so incredible and so touching – and I wondered why no one had told me about it.”

    A second life-changing moment happened as she was cutting across U of T’s St. George campus one day, on her daily trek from her mother’s home in the Annex to her high school, Jarvis Collegiate, on the other side of Yonge Street. She happened to see an advertisement for a campus-wide open house. That weekend, she headed to the astronomy department, at that time housed in the upper floors of the Burton Tower. She emerged from the elevator and saw a table staffed by a professor and some students; they were handing out pamphlets and talking about the stars. Suddenly, it clicked. Astronomy was an actual thing you could study; there were people who had made a career out of it, and she could do that too.

    Though her classes were challenging, she has fond memories of her time as an undergrad at U of T, where she majored in math and physics, but also learned about astronomy at every chance. She recalls that “the opportunities for undergrad research were really great.” For Seager, that included two summers spent studying variable stars – ones that grow brighter and dimmer over time in a regular cycle – at The David Dunlap Observatory, just north of the city. She also served as president of the Royal Canadian Institute’s Youth Science Academy.

    Before heading to Harvard University (US) for graduate school, Seager was determined to have the adventure of a lifetime, far from Toronto’s urban bustle. She joined the Wilderness Canoe Association and prepared for a two-month expedition in Canada’s Far North. It was through the club that she met Mike Wevrick, a young man with a beard and a “mop of ginger hair,” as she put it in her memoir. They married in 1998. By that time, they were already living in Massachusetts, where Seager was hard at work on her PhD – but they came back to Toronto for the wedding, holding a small ceremony in U of T’s Hart House.

    Seager’s supervisor at Harvard was Dimitar Sasselov, who had earned his PhD in astronomy from U of T in 1990. Her dream of becoming an astronomer was taking shape. Yet she often felt that she didn’t quite fit in. As an undergrad, even if she had trouble making friends, she had the familiarity of her home city to fall back on. “Graduate school,” she writes in her memoir, “made it harder for me to imagine my way out of my solitude.” She watched her fellow students “the way biologists might observe a family of apes. They formed bonds with each other, but I couldn’t figure out how or when.”

    But she had Mike, and a few years later she had two sons as well. Work was challenging, but at least she was contributing to a burgeoning field, one with plenty of room for discovery. When Seager started at U of T in 1990, the only planets that astronomers were certain of were the nine that circled our own sun (Pluto had not yet been “demoted”). Soon, however, the hunt for exoplanets began to heat up. The main challenge in observing a planet in a distant solar system is that its feeble light is overwhelmed by the light of its host star. So astronomers found workarounds. First, they learned how to infer the presence of these planets via the gravitational tug they exert on their star. Later, many hundreds of exoplanets were found using the Kepler Space Telescope, which was able to detect the regular dimming of distant stars as an unseen planet passed in front.

    Initially, no one knew how important this new field would be. “At the time, it was quite risky because there were only a few planets known, and many in the community weren’t sure if they were planets,” Seager recalls. “But by the end of the 1990s, exoplanets were here to stay.”

    Seager has investigated many different kinds of these distant worlds. Some of them, she’s found, have both Earth-like properties while also resembling a gas-giant planet, such as Jupiter. Composed mainly of hydrogen and helium, these hybrid planets are called “gas dwarfs.” She has also studied the atmospheres of these planets, developing techniques to analyze their chemical composition from the feeble light astronomers are able to collect from them. Her work on exoplanet atmospheres earned her the Helen B. Warner Prize from The American Astronomical Society (US) in 2007, and the Sackler Prize in the Physical Sciences in 2012. She is also interested – not surprisingly – in whether anything might be alive on any of these worlds, and if so, what evidence of it astronomers might be able to detect, perhaps by looking for unusual chemistry in a planet’s atmosphere. This is known as the hunt for “biosignature gases.” Seager is developing computer models to simulate all manner of possible planetary atmospheres, to see what combinations of gases might hint at life down below.

    Further recognition followed. Seager was a tenured professor at MIT by her mid-30s; she was awarded a MacArthur “genius” fellowship a few years later. But her intense commitment to her work took a toll; as she relates in her memoir, she and Mike were drifting apart. And then things got worse. They learned that Mike was suffering from a rare type of intestine cancer. He died just a few days after Seager’s 40th birthday. His passing left her distraught and disoriented: “When you lose someone,” she writes in The Smallest Lights, “their dying doesn’t stop with their death. You lose them a thousand times in a thousand ways. You say a thousand goodbyes. You hold a thousand funerals.” With the help of a group of local women who had also lost their husbands – she calls the informal club the Widows of Concord – she found the strength to carry on.

    How can one get a better look at an exoplanet? One obvious idea – obvious on paper, at least – is to somehow block out the light from the host star. For more than a decade now, Seager has been part of a team pushing for a project called Starshade – an ambitious venture that would see a large, flower-shaped disk, perhaps 30 metres across, launched into space.

    It would work in tandem with a space-based observatory, such as the planned Nancy Grace Roman Space Telescope.

    The telescope would aim at a particular star, while Starshade, positioned strategically some 30,000 kilometres away but exactly in line with the star, would block out the star’s light, revealing the adjacent planet. (Why the unusual shape? Because, physicists have shown, a sunflower-like shape minimizes the amount of diffracted light, yielding the sharpest image.) Starshade would be costly, of course. Seager is hopeful that the project is reasonably high on NASA’s list of priorities – but U.S. astronomers are currently in the middle of a once-per-decade project review and it remains to be seen which proposals get the green light. Seager is hopeful. “I’m going to do my very best to make Starshade, or something like it, a reality.”

    While Seager’s focus has been the search for habitable worlds beyond our solar system, she also believes there are potential discoveries to be made closer to home. Last fall, she was part of the team that claimed to have detected the chemical phosphine in the atmosphere of Venus. While that claim is still being scrutinized, it seems that something unusual is happening in the planet’s clouds. (On Earth, phosphine is typically associated with microorganisms, but the team acknowledged that the gas might be created by some unknown chemical process.) Whatever is going on, it was enough to spark the interest of Breakthrough Initiatives, a group established by tech billionaire Yuri Milner. The organization recently provided funding for Seager to lead a planned project to study Venus’s atmosphere in more detail. Whatever they find on Venus, Seager is certain the investigation will be an invaluable warm-up for the future study of exoplanet atmospheres and any signs of life they may harbour.

    Seager is a popular draw on the science lecture circuit, and in 2013 The Royal Astronomical Society (CA), a nation-wide collective of amateur astronomy clubs, asked Seager if she would speak at their annual general assembly, to be held that summer in Thunder Bay, Ontario. She eagerly accepted – and that’s where she met a tall, handsome man named Charles Darrow. Like Seager, Darrow was a long-time night sky enthusiast, though he was happy enough to pursue it as a hobby, gazing at the stars from his cottage on Georgian Bay. With Darrow in southern Ontario and Seager in Massachusetts, their relationship began via phone calls and Skype. “We were pioneers of virtual dating,” Darrow jokes. They married in 2015.

    While Seager’s research has focused on distant stars and planets, she has also discovered things about herself – including the very recent realization that she is autistic. The revelation came following a 2016 New York Times Magazine profile in which the reporter described Seager’s solitary nature, her disinterest in small talk, and her ability to latch onto every new project with laser-like intensity. A friend whose wife is an autism specialist emailed her after reading the article. Seager’s first thought, as she writes in her memoir, was that she was “too old not to know such a basic fact” about herself – but she consulted with a specialist, who soon confirmed it. “It was a huge relief,” she recounted over Zoom. “I’m still awkward and different, but I’m happy to have the diagnosis.” She says she’s often approached by young scientists, especially women, who tell her about their own concerns about fitting in, as a result of being diagnosed with Autism Spectrum Disorder. Seager does what she can to encourage and support them. She also believes her condition has helped her excel in science. “I’m so good at my job, probably because I have autism.”

    Our conversation turns once again to the stars. Through all the highs and lows, they have been there. They will always be there, instilling awe and providing a measure of solace. “It just somehow feels comforting,” she says. “It feels wonderful, to know that there’s something bigger than all of us.”

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of Toronto (CA) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen’s Park. It was founded by royal charter in 1827 as King’s College, the oldest university in the province of Ontario.

    Originally controlled by the Church of England, the university assumed its present name in 1850 upon becoming a secular institution.

    As a collegiate university, it comprises eleven colleges each with substantial autonomy on financial and institutional affairs and significant differences in character and history. The university also operates two satellite campuses located in Scarborough and Mississauga.

    University of Toronto has evolved into Canada’s leading institution of learning, discovery and knowledge creation. We are proud to be one of the world’s top research-intensive universities, driven to invent and innovate.

    Our students have the opportunity to learn from and work with preeminent thought leaders through our multidisciplinary network of teaching and research faculty, alumni and partners.

    The ideas, innovations and actions of more than 560,000 graduates continue to have a positive impact on the world.

    Academically, the University of Toronto is noted for movements and curricula in literary criticism and communication theory, known collectively as the Toronto School.

    The university was the birthplace of insulin and stem cell research, and was the site of the first electron microscope in North America; the identification of the first black hole Cygnus X-1; multi-touch technology, and the development of the theory of NP-completeness.

    The university was one of several universities involved in early research of deep learning. It receives the most annual scientific research funding of any Canadian university and is one of two members of the Association of American Universities (US) outside the United States, the other being McGill(CA).

    The Varsity Blues are the athletic teams that represent the university in intercollegiate league matches, with ties to gridiron football, rowing and ice hockey. The earliest recorded instance of gridiron football occurred at University of Toronto’s University College in November 1861.

    The university’s Hart House is an early example of the North American student centre, simultaneously serving cultural, intellectual, and recreational interests within its large Gothic-revival complex.

    The University of Toronto has educated three Governors General of Canada, four Prime Ministers of Canada, three foreign leaders, and fourteen Justices of the Supreme Court. As of March 2019, ten Nobel laureates, five Turing Award winners, 94 Rhodes Scholars, and one Fields Medalist have been affiliated with the university.

    Early history

    The founding of a colonial college had long been the desire of John Graves Simcoe, the first Lieutenant-Governor of Upper Canada and founder of York, the colonial capital. As an University of Oxford (UK)-educated military commander who had fought in the American Revolutionary War, Simcoe believed a college was needed to counter the spread of republicanism from the United States. The Upper Canada Executive Committee recommended in 1798 that a college be established in York.

    On March 15, 1827, a royal charter was formally issued by King George IV, proclaiming “from this time one College, with the style and privileges of a University … for the education of youth in the principles of the Christian Religion, and for their instruction in the various branches of Science and Literature … to continue for ever, to be called King’s College.” The granting of the charter was largely the result of intense lobbying by John Strachan, the influential Anglican Bishop of Toronto who took office as the college’s first president. The original three-storey Greek Revival school building was built on the present site of Queen’s Park.

    Under Strachan’s stewardship, King’s College was a religious institution closely aligned with the Church of England and the British colonial elite, known as the Family Compact. Reformist politicians opposed the clergy’s control over colonial institutions and fought to have the college secularized. In 1849, after a lengthy and heated debate, the newly elected responsible government of the Province of Canada voted to rename King’s College as the University of Toronto and severed the school’s ties with the church. Having anticipated this decision, the enraged Strachan had resigned a year earlier to open Trinity College as a private Anglican seminary. University College was created as the nondenominational teaching branch of the University of Toronto. During the American Civil War the threat of Union blockade on British North America prompted the creation of the University Rifle Corps which saw battle in resisting the Fenian raids on the Niagara border in 1866. The Corps was part of the Reserve Militia lead by Professor Henry Croft.

    Established in 1878, the School of Practical Science was the precursor to the Faculty of Applied Science and Engineering which has been nicknamed Skule since its earliest days. While the Faculty of Medicine opened in 1843 medical teaching was conducted by proprietary schools from 1853 until 1887 when the faculty absorbed the Toronto School of Medicine. Meanwhile the university continued to set examinations and confer medical degrees. The university opened the Faculty of Law in 1887, followed by the Faculty of Dentistry in 1888 when the Royal College of Dental Surgeons became an affiliate. Women were first admitted to the university in 1884.

    A devastating fire in 1890 gutted the interior of University College and destroyed 33,000 volumes from the library but the university restored the building and replenished its library within two years. Over the next two decades a collegiate system took shape as the university arranged federation with several ecclesiastical colleges including Strachan’s Trinity College in 1904. The university operated the Royal Conservatory of Music from 1896 to 1991 and the Royal Ontario Museum from 1912 to 1968; both still retain close ties with the university as independent institutions. The University of Toronto Press was founded in 1901 as Canada’s first academic publishing house. The Faculty of Forestry founded in 1907 with Bernhard Fernow as dean was Canada’s first university faculty devoted to forest science. In 1910, the Faculty of Education opened its laboratory school, the University of Toronto Schools.

    World wars and post-war years

    The First and Second World Wars curtailed some university activities as undergraduate and graduate men eagerly enlisted. Intercollegiate athletic competitions and the Hart House Debates were suspended although exhibition and interfaculty games were still held. The David Dunlap Observatory in Richmond Hill opened in 1935 followed by the University of Toronto Institute for Aerospace Studies in 1949. The university opened satellite campuses in Scarborough in 1964 and in Mississauga in 1967. The university’s former affiliated schools at the Ontario Agricultural College and Glendon Hall became fully independent of the University of Toronto and became part of University of Guelph (CA) in 1964 and York University (CA) in 1965 respectively. Beginning in the 1980s reductions in government funding prompted more rigorous fundraising efforts.

    Since 2000

    In 2000 Kin-Yip Chun was reinstated as a professor of the university after he launched an unsuccessful lawsuit against the university alleging racial discrimination. In 2017 a human rights application was filed against the University by one of its students for allegedly delaying the investigation of sexual assault and being dismissive of their concerns. In 2018 the university cleared one of its professors of allegations of discrimination and antisemitism in an internal investigation after a complaint was filed by one of its students.

    The University of Toronto was the first Canadian university to amass a financial endowment greater than c. $1 billion in 2007. On September 24, 2020 the university announced a $250 million gift to the Faculty of Medicine from businessman and philanthropist James C. Temerty- the largest single philanthropic donation in Canadian history. This broke the previous record for the school set in 2019 when Gerry Schwartz and Heather Reisman jointly donated $100 million for the creation of a 750,000-square foot innovation and artificial intelligence centre.


    Since 1926 the University of Toronto has been a member of the Association of American Universities (US) a consortium of the leading North American research universities. The university manages by far the largest annual research budget of any university in Canada with sponsored direct-cost expenditures of $878 million in 2010. In 2018 the University of Toronto was named the top research university in Canada by Research Infosource with a sponsored research income (external sources of funding) of $1,147.584 million in 2017. In the same year the university’s faculty averaged a sponsored research income of $428,200 while graduate students averaged a sponsored research income of $63,700. The federal government was the largest source of funding with grants from the Canadian Institutes of Health Research; the Natural Sciences and Engineering Research Council; and the Social Sciences and Humanities Research Council amounting to about one-third of the research budget. About eight percent of research funding came from corporations- mostly in the healthcare industry.

    The first practical electron microscope was built by the physics department in 1938. During World War II the university developed the G-suit- a life-saving garment worn by Allied fighter plane pilots later adopted for use by astronauts.Development of the infrared chemiluminescence technique improved analyses of energy behaviours in chemical reactions. In 1963 the asteroid 2104 Toronto was discovered in the David Dunlap Observatory (CA) in Richmond Hill and is named after the university. In 1972 studies on Cygnus X-1 led to the publication of the first observational evidence proving the existence of black holes. Toronto astronomers have also discovered the Uranian moons of Caliban and Sycorax; the dwarf galaxies of Andromeda I, II and III; and the supernova SN 1987A. A pioneer in computing technology the university designed and built UTEC- one of the world’s first operational computers- and later purchased Ferut- the second commercial computer after UNIVAC I. Multi-touch technology was developed at Toronto with applications ranging from handheld devices to collaboration walls. The AeroVelo Atlas which won the Igor I. Sikorsky Human Powered Helicopter Competition in 2013 was developed by the university’s team of students and graduates and was tested in Vaughan.

    The discovery of insulin at the University of Toronto in 1921 is considered among the most significant events in the history of medicine. The stem cell was discovered at the university in 1963 forming the basis for bone marrow transplantation and all subsequent research on adult and embryonic stem cells. This was the first of many findings at Toronto relating to stem cells including the identification of pancreatic and retinal stem cells. The cancer stem cell was first identified in 1997 by Toronto researchers who have since found stem cell associations in leukemia; brain tumors; and colorectal cancer. Medical inventions developed at Toronto include the glycaemic index; the infant cereal Pablum; the use of protective hypothermia in open heart surgery; and the first artificial cardiac pacemaker. The first successful single-lung transplant was performed at Toronto in 1981 followed by the first nerve transplant in 1988; and the first double-lung transplant in 1989. Researchers identified the maturation promoting factor that regulates cell division and discovered the T-cell receptor which triggers responses of the immune system. The university is credited with isolating the genes that cause Fanconi anemia; cystic fibrosis; and early-onset Alzheimer’s disease among numerous other diseases. Between 1914 and 1972 the university operated the Connaught Medical Research Laboratories- now part of the pharmaceutical corporation Sanofi-Aventis. Among the research conducted at the laboratory was the development of gel electrophoresis.

    The University of Toronto is the primary research presence that supports one of the world’s largest concentrations of biotechnology firms. More than 5,000 principal investigators reside within 2 kilometres (1.2 mi) from the university grounds in Toronto’s Discovery District conducting $1 billion of medical research annually. MaRS Discovery District is a research park that serves commercial enterprises and the university’s technology transfer ventures. In 2008, the university disclosed 159 inventions and had 114 active start-up companies. Its SciNet Consortium operates the most powerful supercomputer in Canada.

  • richardmitnick 1:14 pm on June 23, 2021 Permalink | Reply
    Tags: "Mind the Gap- Scientists Use Stellar Mass to Link Exoplanets to Planet-Forming Disks", , , , , Exoplanet Reseach, ,   

    From ALMA(CL) : “Mind the Gap- Scientists Use Stellar Mass to Link Exoplanets to Planet-Forming Disks” 

    From ALMA(CL)/ European Southern Observatory/National Radio Astronomy Observatory(US)/National Astronomical Observatory of Japan(JP)

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
, Tokyo – Japan
    Phone: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Bárbara Ferreira
    ESO Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: pio@eso.org
    Amy C. Oliver
    Public Information & News Manager
    National Radio Astronomical Observatory (NRAO), USA
    Phone: +1 434 242 9584
    Email: aoliver@nrao.edu

    All general references:
    ALMA Observatory (CL)
    European Southern Observatory(EU)
    National Astronomical Observatory of Japan(JP)
    National Radio Astronomy Observatory(US)

    Protoplanetary disks are classified into three main categories: transition, ring, or extended. These false-color images from the Atacama Large Millimeter/submillimeter Array (ALMA) show these classifications in stark contrast. On left: the ring disk of RU Lup is characterized by narrow gaps thought to be carved by giant planets with masses ranging between a Neptune mass and a Jupiter mass. Middle: the transition disk of J1604.3-2130 is characterized by a large inner cavity thought to be carved by planets more massive than Jupiter, also known as Super-Jovian planets. On right: the compact disk of Sz104 is believed not to contain giant planets, as it lacks the telltale gaps and cavities associated with the presence of giant planets. Credit: S. Dagnello (NRAO) ALMA (ESO/NAOJ/NRAO).

    Using data for more than 500 young stars observed with the Atacama Large Millimeter/submillimeter Array (ALMA), scientists have uncovered a direct link between protoplanetary disk structures—the planet-forming disks that surround stars—and planet demographics. The survey proves that higher mass stars are more likely to be surrounded by disks with “gaps” in them and that these gaps directly correlate to the high occurrence of observed giant exoplanets around such stars. These results provide scientists with a window back through time, allowing them to predict what exoplanetary systems looked like through each stage of their formation.

    “We found a strong correlation between gaps in protoplanetary disks and stellar mass, which can be linked to the presence of large, gaseous exoplanets,” said Nienke van der Marel, a Banting fellow in the Department of Physics and Astronomy at the University of Victoria (CA) in British Columbia (CA), and the primary author on the research. “Higher mass stars have relatively more disks with gaps than lower mass stars, consistent with the already known correlations in exoplanets, where higher mass stars more often host gas-giant exoplanets. These correlations directly tell us that gaps in planet-forming disks are most likely caused by giant planets of Neptune mass and above.”

    Gaps in protoplanetary disks have long been considered as overall evidence of planet formation. However, there has been some skepticism due to the observed orbital distance between exoplanets and their stars. “One of the primary reasons that scientists have been skeptical about the link between gaps and planets before is that exoplanets at wide orbits of tens of astronomical units are rare. However, exoplanets at smaller orbits, between one and ten astronomical units, are much more common,” said Gijs Mulders, assistant professor of astronomy at Universidad Adolfo Ibáñez in Santiago, Chile, and co-author on the research. “We believe that planets that clear the gaps will migrate inwards later on.”

    The new study is the first to show that the number of gapped disks in these regions matches the number of giant exoplanets in a star system. “Previous studies indicated that there were many more gapped disks than detected giant exoplanets,” said Mulders. “Our study shows that there are enough exoplanets to explain the observed frequency of the gapped disks at different stellar masses.”

    The correlation also applies to star systems with low-mass stars, where scientists are more likely to find massive rocky exoplanets, also known as Super-Earths. Van der Marel, who will become an assistant professor at Leiden University in the Netherlands beginning September 2021 said, “Lower mass stars have more rocky Super-Earths—between an Earth mass and a Neptune mass. Disks without gaps, which are more compact, lead to the formation of Super-Earths.”

    This link between stellar mass and planetary demographics could help scientists identify which stars to target in the search for rocky planets throughout the Milky Way. “This new understanding of stellar mass dependencies will help to guide the search for small, rocky planets like Earth in the solar neighborhood,” said Mulders, who is also a part of the NASA-funded Alien Earths team. “We can use the stellar mass to connect the planet-forming disks around young stars to exoplanets around mature stars. When an exoplanet is detected, the planet-forming material is usually gone. So the stellar mass is a ‘tag’ that tells us what the planet-forming environment might have looked like for these exoplanets.”

    And what it all comes down to is dust. “An important element of planet formation is the influence of dust evolution,” said van der Marel. “Without giant planets, dust will always drift inwards, creating the optimal conditions for the formation of smaller, rocky planets close to the star.”

    The current research was conducted using data for more than 500 objects observed in prior studies using ALMA’s high-resolution Band 6 and Band 7 antennas. At present, ALMA is the only telescope that can image the distribution of millimeter-dust at high enough angular resolution to resolve the dust disks and reveal its substructure, or lack thereof. “Over the past five years, ALMA has produced many snapshot surveys of nearby star-forming regions resulting in hundreds of measurements of disk dust mass, size, and morphology,” said van der Marel. “The large number of observed disk properties has allowed us to make a statistical comparison of protoplanetary disks to the thousands of discovered exoplanets. This is the first time that a stellar mass dependency of gapped disks and compact disks has been successfully demonstrated using the ALMA telescope.”

    “Our new findings link the beautiful gap structures in disks observed with ALMA directly to the properties of the thousands of exoplanets detected by the NASA Kepler mission and other exoplanet surveys,” said Mulders. “Exoplanets and their formation help us place the origins of the Earth and the Solar System in the context of what we see happening around other stars.”

    Additional Information

    The results of this research appeared as “A stellar mass dependence of structured disks: a possible link with exoplanet demographics” by N. van der Marel et al. in The Astrophysical Journal.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Atacama Large Millimeter/submillimeter Array (ALMA)(CL) , an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by European Southern Observatory(EU), on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (US) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
    NRAO Small
    ESO 50 Large

    ALMA is a time machine!

    ALMA-In Search of our Cosmic Origins

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