HD 97048 or CU Chamaeleontis is a

Herbig Ae/Be star A Herbig Ae/Be star (HAeBe) is a pre-main-sequence star – a young () star of spectral types A or B. These stars are still embedded in gas-dust envelopes and are sometimes accompanied by circumstellar disks. Hydrogen and calcium emission lines ...

away in the constellation

Chamaeleon Chamaeleon () is a small constellation in the deep southern sky. It is named after the chameleon, a kind of lizard. It was first defined in the 16th century. History Chamaeleon was one of twelve constellations created by Petrus Plancius f ...

. It is a

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

embedded in a dust cloud containing a

stellar nursery Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"— collapse and form stars. As a branch of astronomy, star formation inclu ...

, and is itself surrounded by a dust disk. HD 97048 is a young star still contracting towards the

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

. Its brightness varies between magnitudes 8.38 and 8.48 and it is classified as an Orion variable. It was given the

variable star designation In astronomy, a variable-star designation is a unique identifier given to variable stars. It extends the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constellation in whic ...

CU Chamaeleontis in 1981. Its

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

is also variable. The spectral class is usually given as A0 or B9, sometimes with a

giant In folklore, giants (from Ancient Greek: ''wiktionary:gigas, gigas'', cognate wiktionary:giga-, giga-) are beings of humanoid appearance, but are at times prodigious in size and strength or bear an otherwise notable appearance. The word ''gia ...

luminosity class In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

, sometimes main sequence. The spectrum shows strong variable

emission line A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used ...

s indicative of a shell surrounding the star. HD 97048 is a member of the Chamaeleon T1

stellar association A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more visible stars. An association is primarily identified by commonalities in i ...

and is still embedded within the dark

molecular cloud A molecular cloud—sometimes called a stellar nursery if star formation is occurring within—is a type of interstellar cloud of which the density and size permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, ...

that it is forming from. It illuminates a small

reflection nebula In astronomy, reflection nebulae are interstellar cloud, clouds of Cosmic dust, interstellar dust which might reflect the light of a nearby star or stars. The energy from the nearby stars is insufficient to Ionization, ionize the gas of the nebu ...

against the dark cloud.

Planetary system

This star has a substantial dust disk having a central cavity with a 40−46 AU radius The disk has a

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

gas velocity kink and intensity gap at 130 AUs, which is suspected to be caused by a superjovian planet. In 2019, HCO⁺ ion and

Hydrogen cyanide Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

emission was detected from the disk, suggesting a large amount of gas is orbiting beyond 200 AU radius. HD 97048 disk

In the system a kink in the velocity of

gas (CO 3–2) as well as a gap in the dust emission of the disk are seen as evidence for a jovian

protoplanet A protoplanet is a large planetary embryo that originated within a protoplanetary disk and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitatio ...

. The protoplanet is located at 130 au from the star and has a mass of about 2.5 Jupiter masses. It is one of the lowest mass protoplanets discovered as of 2023.

References

{{DEFAULTSORT:HD 97048 Chamaeleon Circumstellar disks 097048 Chamaeleontis, CU 054413 CD-76 488 Herbig Ae/Be stars Hypothetical planetary systems