Caroline Herschel, tiny and fierce of will, was born in 1750, moved from her birthplace in Germany to England when she was 22 and worked as assistant, amanuensis and late-night stargazing companion to her beloved elder brother, astronomer William Herschel. She lived for nearly a century, keeping a journal for much of that time and composing numerous letters and two autobiographies. Before she died, she was awarded medals and elected an Honorary Fellow of the Royal Astronomical Society .

Look her up, if you want to learn the facts of her remarkable life; some excellent biographies draw on that wealth of documentation. But if you want to get a sense of how her life might have felt, then turn to “The Stargazer’s Sister,” Carrie Brown’s intriguing seventh novel. Wisely, sometimes brilliantly, Brown skips over much of the familiar material, instead training her gaze on the blanks in the record and emphasizing experiences a biographer might scant. In the process, she avoids casting Herschel as a feminist heroine whose contributions were unjustly suppressed. Her Lina (as William called her) is not a historical personage but a sympathetic fictional character.

Time in this novel passes as eccentrically as it does in our experience. Although Lina famously discovered eight comets on her own, her years as a “great comet huntress” slip by in a paragraph. Meanwhile, her early childhood in Hanover, when William, nearly 12 years her senior, told her marvelous tales about the creatures who “live on the moon and even on the sun . . . Lunarians, giants with long slender legs and faces calm as lakes,” fills nearly a quarter of the novel. Similarly, her intense and emotionally vivid first years in England, when she and William worked closely together and she was adapting to a new life, filled with marvels, occupy 150 pages. “How strange it seems,” Brown writes, “that it should be her brother who would become the first man in history — in recorded history, at least — to discover a planet, to expand the universe around them as surely as if he had put his shoulder to the ceiling of the sky and pushed against it, heaving it open like a door.”

That lovely physical image suggests Brown’s approach, always firmly rooted in the senses. She sketches Lina’s astronomical work lightly, instead showing what drove her toward that work: her responsive nature, her sense of wonder at the natural world, her longing to be useful and her deep love for her brother, which has a distinctly erotic component. Lina notices and appreciates William’s strong chest and shoulders, and she cherishes his rare touch. Even more does she cherish the long nights when, absorbed in their shared work, William depends entirely on her.

Novelist Carrie Brown. (Aaron Mahler)

A love story, then — but unusual in being about a brother and sister, and what they accomplished together. In precise and vivid prose, Brown conveys the texture of daily life for a woman with both domestic responsibilities (until William’s marriage, Lina managed every aspect of his household) and complex intellectual tasks:

“She copies William’s letters, so that he may keep a record of them.

“She washes their clothing.

“She keeps on the table in the kitchen a list of the mathematical equations needed to compute exact positions of celestial objects, so that she might refer to it throughout the day, trying to memorize them.

“She plans and cooks the household’s meals.

“She adds and subtracts figures from the accounts, gauges the weather and if there might be sufficient hours fine enough to hang out washing that day, calculates how long it will take her to copy the musical scores William has set aside for her.

“She would never have imagined her head could hold so much.”

So intimate is their early partnership that when William grinds the mirrors for his telescopes, unable to stop lest he destroy the curve, Lina feeds him morsels of food like a mother bird. Having renounced “the kind of love shared between husbands and wives,” she believes in “this other, different future, a different kind of love, her love for William.” But although William appreciates all she does, his affection for her is more measured — and when, at the age of nearly 50, he decides to marry, Lina’s sense of betrayal is terrible. Their intellectual partnership continues during William’s remaining 34 years, but Lina’s emotional life is savaged — signaled, in the novel, by the swift march through the following decades.

In her impressionistic portrait, Brown moves some events in time, combines others and scants certain family members — entirely omitting, for example, William’s son, John, a famous scientist in his own right. Those compressions and alterations help smooth what might have been an unwieldy mass of material into a strong arc. Her invented characters for the most part work similarly to dramatize longings that can only be intuited (although Lina’s love affair with an elderly amateur astronomer rang false to me). The result is a satisfying romance about what it might have been like to be a woman who “thought she was coming to England to keep house for William. Instead, she is being ushered into a place where the size of the universe is in question.”

Andrea Barrett’s most recent book is “Archangel,” a collection of short fiction.

The Stargazer’s Sister

By Carrie Brown

Pantheon. 332 pp. 25.95