PHL 293B, also known as Kinman's dwarf, is a low- metallicity blue compact dwarf galaxy about 22.6 Mpc from the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

in the constellation

Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainme ...

. It had a very likely associated, notable, blue-light, long-lived star with constant outbursts or a large supernova observed to have faded and which then disappeared. Although this bright visible jet-producing object responsible for broad hydrogen

emission line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identi ...

s with

P Cygni profile P Cygni (34 Cygni) is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in ''Uranometria'' as a nova. Located about 5,300 light-years (1,560 parsecs) from Earth, it is a hypergiant ...

s was widely considered to be a luminous blue variable ejecting matter, other studies posited the mentioned, competing, explanations for the bright light source within.

Observation history

PHL 293 was first listed as entry ''293'' in a catalogue of faint blue stars published by Guillermo Haro and

Willem Jacob Luyten Willem Jacob Luyten (March 7, 1899 – November 21, 1994) was a Dutch-American astronomer. "Willem Jacob Luyten", ''Marquis Who's Who'', 2006. Life Jacob Luyten was born in Semarang, Java, at the time part of the Dutch East Indies. His ...

in 1962. In 1965, Thomas Kinman observed two faint possible companions to it, about away, which he dubbed A and B. HL 293B, sometimes called Kinman's Dwarf, was noted to be an extragalactic, nonstellar object, with a jet, approximately 22.6 Mpc away from Earth. The acronym PHL has since been applied to distinguish it from other HL catalogues; it is most commonly referred to by astronomers as PHL 293B. The galaxy was identified as a blue compact dwarf, a type of small

irregular galaxy An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, ...

undergoing a strong burst of star formation. The spectrum of PHL 293B is unusual both for its low metallicity and for broad hydrogen

s with

s. These are interpreted as being from a large luminous blue variable star in the galaxy. The star is believed to have been undergoing an outburst during previous observations, an interpretation is disputed by some publications. An alternative explanation would be a long-lived type IIn supernova, similar to the transient event of SDSS1133. These emission features in the spectrum of the galaxy faded during 2019 and by the end of the year had disappeared (at least visibly), likely due to the disappearance of a bright star of the galaxy.

References

{{DEFAULTSORT:PHL 293B Aquarius (constellation) Dwarf galaxies SDSS objects Luminous blue variables

Observation history

See also

References